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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / b627eab0402edabb19c702fd1f04c6c59ee2b339 / . / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
Reid Spencer3921c742004-08-26 20:44:00 +0000[diff] [blame]6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
8 <meta name="description"
9 content="LLVM Assembly Language Reference Manual.">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]14
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]15<div class="doc_title"> LLVM Language Reference Manual </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a></li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]24 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]25 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]26 <li><a href="#functionstructure">Functions</a></li>
Anton Korobeynikova80e1182007-04-28 13:45:00 +0000[diff] [blame]27 <li><a href="aliasstructure">Aliases</a>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]28 <li><a href="#paramattrs">Parameter Attributes</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]29 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]30 <li><a href="#datalayout">Data Layout</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]31 </ol>
32 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]33 <li><a href="#typesystem">Type System</a>
34 <ol>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]35 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]36 <ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]37 <li><a href="#t_classifications">Type Classifications</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]38 </ol>
39 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]40 <li><a href="#t_derived">Derived Types</a>
41 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]42 <li><a href="#t_array">Array Type</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]43 <li><a href="#t_function">Function Type</a></li>
44 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]45 <li><a href="#t_struct">Structure Type</a></li>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]46 <li><a href="#t_pstruct">Packed Structure Type</a></li>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]47 <li><a href="#t_vector">Vector Type</a></li>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]48 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]49 </ol>
50 </li>
51 </ol>
52 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]53 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]54 <ol>
55 <li><a href="#simpleconstants">Simple Constants</a>
56 <li><a href="#aggregateconstants">Aggregate Constants</a>
57 <li><a href="#globalconstants">Global Variable and Function Addresses</a>
58 <li><a href="#undefvalues">Undefined Values</a>
59 <li><a href="#constantexprs">Constant Expressions</a>
60 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]61 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]62 <li><a href="#othervalues">Other Values</a>
63 <ol>
64 <li><a href="#inlineasm">Inline Assembler Expressions</a>
65 </ol>
66 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]67 <li><a href="#instref">Instruction Reference</a>
68 <ol>
69 <li><a href="#terminators">Terminator Instructions</a>
70 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]71 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
72 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]73 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
74 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]75 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]76 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]77 </ol>
78 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]79 <li><a href="#binaryops">Binary Operations</a>
80 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]81 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
82 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
83 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]84 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
85 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
86 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]87 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
88 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
89 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]90 </ol>
91 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]92 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
93 <ol>
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]94 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
95 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
96 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]97 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]98 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]99 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]100 </ol>
101 </li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]102 <li><a href="#vectorops">Vector Operations</a>
103 <ol>
104 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
105 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
106 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]107 </ol>
108 </li>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]109 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]110 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]111 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
112 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
113 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]114 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
115 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
116 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]117 </ol>
118 </li>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]119 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]120 <ol>
121 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
122 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
123 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
124 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
125 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]126 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
127 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
128 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
129 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]130 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
131 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]132 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]133 </ol>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]134 <li><a href="#otherops">Other Operations</a>
135 <ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]136 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
137 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]138 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]139 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]140 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]141 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]142 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]143 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]144 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]145 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]146 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]147 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]148 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
149 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]150 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
151 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
152 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]153 </ol>
154 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]155 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
156 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]157 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
158 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
159 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]160 </ol>
161 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]162 <li><a href="#int_codegen">Code Generator Intrinsics</a>
163 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]164 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
165 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
166 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
167 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
168 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
169 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
170 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]171 </ol>
172 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]173 <li><a href="#int_libc">Standard C Library Intrinsics</a>
174 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]175 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
176 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
177 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
178 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
179 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]180 </ol>
181 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]182 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]183 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]184 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]185 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
186 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
187 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]188 <li><a href="#int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic </a></li>
189 <li><a href="#int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]190 </ol>
191 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]192 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]193 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]194 </ol>
195 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]196</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]197
198<div class="doc_author">
199 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
200 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]201</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]202
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]203<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]204<div class="doc_section"> <a name="abstract">Abstract </a></div>
205<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]206
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]207<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]208<p>This document is a reference manual for the LLVM assembly language.
209LLVM is an SSA based representation that provides type safety,
210low-level operations, flexibility, and the capability of representing
211'all' high-level languages cleanly. It is the common code
212representation used throughout all phases of the LLVM compilation
213strategy.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]214</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]215
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]216<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]217<div class="doc_section"> <a name="introduction">Introduction</a> </div>
218<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]219
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]220<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]221
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]222<p>The LLVM code representation is designed to be used in three
223different forms: as an in-memory compiler IR, as an on-disk bytecode
224representation (suitable for fast loading by a Just-In-Time compiler),
225and as a human readable assembly language representation. This allows
226LLVM to provide a powerful intermediate representation for efficient
227compiler transformations and analysis, while providing a natural means
228to debug and visualize the transformations. The three different forms
229of LLVM are all equivalent. This document describes the human readable
230representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]231
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]232<p>The LLVM representation aims to be light-weight and low-level
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]233while being expressive, typed, and extensible at the same time. It
234aims to be a "universal IR" of sorts, by being at a low enough level
235that high-level ideas may be cleanly mapped to it (similar to how
236microprocessors are "universal IR's", allowing many source languages to
237be mapped to them). By providing type information, LLVM can be used as
238the target of optimizations: for example, through pointer analysis, it
239can be proven that a C automatic variable is never accessed outside of
240the current function... allowing it to be promoted to a simple SSA
241value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]242
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]243</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]244
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]245<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]246<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]247
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]248<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]249
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]250<p>It is important to note that this document describes 'well formed'
251LLVM assembly language. There is a difference between what the parser
252accepts and what is considered 'well formed'. For example, the
253following instruction is syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]254
255<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]256 %x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]257</pre>
258
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]259<p>...because the definition of <tt>%x</tt> does not dominate all of
260its uses. The LLVM infrastructure provides a verification pass that may
261be used to verify that an LLVM module is well formed. This pass is
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]262automatically run by the parser after parsing input assembly and by
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]263the optimizer before it outputs bytecode. The violations pointed out
264by the verifier pass indicate bugs in transformation passes or input to
265the parser.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]266
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]267<!-- Describe the typesetting conventions here. --> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]268
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]269<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]270<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]271<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]272
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]273<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]274
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]275<p>LLVM uses three different forms of identifiers, for different
276purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]277
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]278<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]279 <li>Named values are represented as a string of characters with a '%' prefix.
280 For example, %foo, %DivisionByZero, %a.really.long.identifier. The actual
281 regular expression used is '<tt>%[a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
282 Identifiers which require other characters in their names can be surrounded
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]283 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]284 in a name.</li>
285
286 <li>Unnamed values are represented as an unsigned numeric value with a '%'
287 prefix. For example, %12, %2, %44.</li>
288
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]289 <li>Constants, which are described in a <a href="#constants">section about
290 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]291</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]292
293<p>LLVM requires that values start with a '%' sign for two reasons: Compilers
294don't need to worry about name clashes with reserved words, and the set of
295reserved words may be expanded in the future without penalty. Additionally,
296unnamed identifiers allow a compiler to quickly come up with a temporary
297variable without having to avoid symbol table conflicts.</p>
298
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]299<p>Reserved words in LLVM are very similar to reserved words in other
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]300languages. There are keywords for different opcodes
301('<tt><a href="#i_add">add</a></tt>',
302 '<tt><a href="#i_bitcast">bitcast</a></tt>',
303 '<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]304href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]305and others. These reserved words cannot conflict with variable names, because
306none of them start with a '%' character.</p>
307
308<p>Here is an example of LLVM code to multiply the integer variable
309'<tt>%X</tt>' by 8:</p>
310
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]311<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]312
313<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]314 %result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]315</pre>
316
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]317<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]318
319<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]320 %result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]321</pre>
322
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]323<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]324
325<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]326 <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
327 <a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
328 %result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]329</pre>
330
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]331<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
332important lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]333
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]334<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]335
336 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
337 line.</li>
338
339 <li>Unnamed temporaries are created when the result of a computation is not
340 assigned to a named value.</li>
341
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]342 <li>Unnamed temporaries are numbered sequentially</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]343
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]344</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]345
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]346<p>...and it also shows a convention that we follow in this document. When
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]347demonstrating instructions, we will follow an instruction with a comment that
348defines the type and name of value produced. Comments are shown in italic
349text.</p>
350
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]351</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]352
353<!-- *********************************************************************** -->
354<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
355<!-- *********************************************************************** -->
356
357<!-- ======================================================================= -->
358<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
359</div>
360
361<div class="doc_text">
362
363<p>LLVM programs are composed of "Module"s, each of which is a
364translation unit of the input programs. Each module consists of
365functions, global variables, and symbol table entries. Modules may be
366combined together with the LLVM linker, which merges function (and
367global variable) definitions, resolves forward declarations, and merges
368symbol table entries. Here is an example of the "hello world" module:</p>
369
370<pre><i>; Declare the string constant as a global constant...</i>
371<a href="#identifiers">%.LC0</a> = <a href="#linkage_internal">internal</a> <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]372 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]373
374<i>; External declaration of the puts function</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]375<a href="#functionstructure">declare</a> i32 %puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]376
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 Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]400</div>
401
402<!-- ======================================================================= -->
403<div class="doc_subsection">
404 <a name="linkage">Linkage Types</a>
405</div>
406
407<div class="doc_text">
408
409<p>
410All Global Variables and Functions have one of the following types of linkage:
411</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]412
413<dl>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]414
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]415 <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]416
417 <dd>Global values with internal linkage are only directly accessible by
418 objects in the current module. In particular, linking code into a module with
419 an internal global value may cause the internal to be renamed as necessary to
420 avoid collisions. Because the symbol is internal to the module, all
421 references can be updated. This corresponds to the notion of the
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]422 '<tt>static</tt>' keyword in C.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]423 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]424
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]425 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]426
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]427 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
428 the same name when linkage occurs. This is typically used to implement
429 inline functions, templates, or other code which must be generated in each
430 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
431 allowed to be discarded.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]432 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]433
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]434 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]435
436 <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage,
437 except that unreferenced <tt>weak</tt> globals may not be discarded. This is
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]438 used for globals that may be emitted in multiple translation units, but that
439 are not guaranteed to be emitted into every translation unit that uses them.
440 One example of this are common globals in C, such as "<tt>int X;</tt>" at
441 global scope.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]442 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]443
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]444 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]445
446 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
447 pointer to array type. When two global variables with appending linkage are
448 linked together, the two global arrays are appended together. This is the
449 LLVM, typesafe, equivalent of having the system linker append together
450 "sections" with identical names when .o files are linked.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]451 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]452
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]453 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
454 <dd>The semantics of this linkage follow the ELF model: the symbol is weak
455 until linked, if not linked, the symbol becomes null instead of being an
456 undefined reference.
457 </dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]458
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]459 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]460
461 <dd>If none of the above identifiers are used, the global is externally
462 visible, meaning that it participates in linkage and can be used to resolve
463 external symbol references.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]464 </dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]465</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]466
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]467 <p>
468 The next two types of linkage are targeted for Microsoft Windows platform
469 only. They are designed to support importing (exporting) symbols from (to)
470 DLLs.
471 </p>
472
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]473 <dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]474 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
475
476 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
477 or variable via a global pointer to a pointer that is set up by the DLL
478 exporting the symbol. On Microsoft Windows targets, the pointer name is
479 formed by combining <code>_imp__</code> and the function or variable name.
480 </dd>
481
482 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
483
484 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
485 pointer to a pointer in a DLL, so that it can be referenced with the
486 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
487 name is formed by combining <code>_imp__</code> and the function or variable
488 name.
489 </dd>
490
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]491</dl>
492
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]493<p><a name="linkage_external"></a>For example, since the "<tt>.LC0</tt>"
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]494variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
495variable and was linked with this one, one of the two would be renamed,
496preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
497external (i.e., lacking any linkage declarations), they are accessible
Reid Spencerac8d2762007-01-05 00:59:10 +0000[diff] [blame]498outside of the current module.</p>
499<p>It is illegal for a function <i>declaration</i>
500to have any linkage type other than "externally visible", <tt>dllimport</tt>,
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]501or <tt>extern_weak</tt>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]502<p>Aliases can have only <tt>external</tt>, <tt>internal</tt> and <tt>weak</tt>
503linkages.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]504</div>
505
506<!-- ======================================================================= -->
507<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]508 <a name="callingconv">Calling Conventions</a>
509</div>
510
511<div class="doc_text">
512
513<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
514and <a href="#i_invoke">invokes</a> can all have an optional calling convention
515specified for the call. The calling convention of any pair of dynamic
516caller/callee must match, or the behavior of the program is undefined. The
517following calling conventions are supported by LLVM, and more may be added in
518the future:</p>
519
520<dl>
521 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
522
523 <dd>This calling convention (the default if no other calling convention is
524 specified) matches the target C calling conventions. This calling convention
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]525 supports varargs function calls and tolerates some mismatch in the declared
Reid Spencerc28d2bc2006-12-31 21:30:18 +0000[diff] [blame]526 prototype and implemented declaration of the function (as does normal C).
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]527 </dd>
528
529 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
530
531 <dd>This calling convention attempts to make calls as fast as possible
532 (e.g. by passing things in registers). This calling convention allows the
533 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner8cdc5bc2005-05-06 23:08:23 +0000[diff] [blame]534 without having to conform to an externally specified ABI. Implementations of
535 this convention should allow arbitrary tail call optimization to be supported.
536 This calling convention does not support varargs and requires the prototype of
537 all callees to exactly match the prototype of the function definition.
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]538 </dd>
539
540 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
541
542 <dd>This calling convention attempts to make code in the caller as efficient
543 as possible under the assumption that the call is not commonly executed. As
544 such, these calls often preserve all registers so that the call does not break
545 any live ranges in the caller side. This calling convention does not support
546 varargs and requires the prototype of all callees to exactly match the
547 prototype of the function definition.
548 </dd>
549
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]550 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]551
552 <dd>Any calling convention may be specified by number, allowing
553 target-specific calling conventions to be used. Target specific calling
554 conventions start at 64.
555 </dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]556</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]557
558<p>More calling conventions can be added/defined on an as-needed basis, to
559support pascal conventions or any other well-known target-independent
560convention.</p>
561
562</div>
563
564<!-- ======================================================================= -->
565<div class="doc_subsection">
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]566 <a name="visibility">Visibility Styles</a>
567</div>
568
569<div class="doc_text">
570
571<p>
572All Global Variables and Functions have one of the following visibility styles:
573</p>
574
575<dl>
576 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
577
578 <dd>On ELF, default visibility means that the declaration is visible to other
579 modules and, in shared libraries, means that the declared entity may be
580 overridden. On Darwin, default visibility means that the declaration is
581 visible to other modules. Default visibility corresponds to "external
582 linkage" in the language.
583 </dd>
584
585 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
586
587 <dd>Two declarations of an object with hidden visibility refer to the same
588 object if they are in the same shared object. Usually, hidden visibility
589 indicates that the symbol will not be placed into the dynamic symbol table,
590 so no other module (executable or shared library) can reference it
591 directly.
592 </dd>
593
594</dl>
595
596</div>
597
598<!-- ======================================================================= -->
599<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]600 <a name="globalvars">Global Variables</a>
601</div>
602
603<div class="doc_text">
604
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]605<p>Global variables define regions of memory allocated at compilation time
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]606instead of run-time. Global variables may optionally be initialized, may have
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]607an explicit section to be placed in, and may have an optional explicit alignment
608specified. A variable may be defined as "thread_local", which means that it
609will not be shared by threads (each thread will have a separated copy of the
610variable). A variable may be defined as a global "constant," which indicates
611that the contents of the variable will <b>never</b> be modified (enabling better
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]612optimization, allowing the global data to be placed in the read-only section of
613an executable, etc). Note that variables that need runtime initialization
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]614cannot be marked "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]615
616<p>
617LLVM explicitly allows <em>declarations</em> of global variables to be marked
618constant, even if the final definition of the global is not. This capability
619can be used to enable slightly better optimization of the program, but requires
620the language definition to guarantee that optimizations based on the
621'constantness' are valid for the translation units that do not include the
622definition.
623</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]624
625<p>As SSA values, global variables define pointer values that are in
626scope (i.e. they dominate) all basic blocks in the program. Global
627variables always define a pointer to their "content" type because they
628describe a region of memory, and all memory objects in LLVM are
629accessed through pointers.</p>
630
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]631<p>LLVM allows an explicit section to be specified for globals. If the target
632supports it, it will emit globals to the section specified.</p>
633
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]634<p>An explicit alignment may be specified for a global. If not present, or if
635the alignment is set to zero, the alignment of the global is set by the target
636to whatever it feels convenient. If an explicit alignment is specified, the
637global is forced to have at least that much alignment. All alignments must be
638a power of 2.</p>
639
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]640<p>For example, the following defines a global with an initializer, section,
641 and alignment:</p>
642
643<pre>
644 %G = constant float 1.0, section "foo", align 4
645</pre>
646
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]647</div>
648
649
650<!-- ======================================================================= -->
651<div class="doc_subsection">
652 <a name="functionstructure">Functions</a>
653</div>
654
655<div class="doc_text">
656
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]657<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
658an optional <a href="#linkage">linkage type</a>, an optional
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]659<a href="#visibility">visibility style</a>, an optional
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]660<a href="#callingconv">calling convention</a>, a return type, an optional
661<a href="#paramattrs">parameter attribute</a> for the return type, a function
662name, a (possibly empty) argument list (each with optional
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]663<a href="#paramattrs">parameter attributes</a>), an optional section, an
664optional alignment, an opening curly brace, a list of basic blocks, and a
665closing curly brace.
666
667LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
668optional <a href="#linkage">linkage type</a>, an optional
669<a href="#visibility">visibility style</a>, an optional
670<a href="#callingconv">calling convention</a>, a return type, an optional
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]671<a href="#paramattrs">parameter attribute</a> for the return type, a function
672name, a possibly empty list of arguments, and an optional alignment.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]673
674<p>A function definition contains a list of basic blocks, forming the CFG for
675the function. Each basic block may optionally start with a label (giving the
676basic block a symbol table entry), contains a list of instructions, and ends
677with a <a href="#terminators">terminator</a> instruction (such as a branch or
678function return).</p>
679
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]680<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]681executed on entrance to the function, and it is not allowed to have predecessor
682basic blocks (i.e. there can not be any branches to the entry block of a
683function). Because the block can have no predecessors, it also cannot have any
684<a href="#i_phi">PHI nodes</a>.</p>
685
686<p>LLVM functions are identified by their name and type signature. Hence, two
687functions with the same name but different parameter lists or return values are
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]688considered different functions, and LLVM will resolve references to each
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]689appropriately.</p>
690
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]691<p>LLVM allows an explicit section to be specified for functions. If the target
692supports it, it will emit functions to the section specified.</p>
693
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]694<p>An explicit alignment may be specified for a function. If not present, or if
695the alignment is set to zero, the alignment of the function is set by the target
696to whatever it feels convenient. If an explicit alignment is specified, the
697function is forced to have at least that much alignment. All alignments must be
698a power of 2.</p>
699
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]700</div>
701
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]702
703<!-- ======================================================================= -->
704<div class="doc_subsection">
705 <a name="aliasstructure">Aliases</a>
706</div>
707<div class="doc_text">
708 <p>Aliases act as "second name" for the aliasee value (which can be either
Anton Korobeynikova80e1182007-04-28 13:45:00 +0000[diff] [blame]709 function or global variable or bitcast of global value). Aliases may have an
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]710 optional <a href="#linkage">linkage type</a>, and an
711 optional <a href="#visibility">visibility style</a>.</p>
712
713 <h5>Syntax:</h5>
714
715 <pre>
716 @&lt;Name&gt; = [Linkage] [Visibility] alias &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
717 </pre>
718
719</div>
720
721
722
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]723<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]724<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
725<div class="doc_text">
726 <p>The return type and each parameter of a function type may have a set of
727 <i>parameter attributes</i> associated with them. Parameter attributes are
728 used to communicate additional information about the result or parameters of
729 a function. Parameter attributes are considered to be part of the function
730 type so two functions types that differ only by the parameter attributes
731 are different function types.</p>
732
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]733 <p>Parameter attributes are simple keywords that follow the type specified. If
734 multiple parameter attributes are needed, they are space separated. For
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]735 example:</p><pre>
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]736 %someFunc = i16 (i8 sext %someParam) zext
737 %someFunc = i16 (i8 zext %someParam) zext</pre>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]738 <p>Note that the two function types above are unique because the parameter has
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]739 a different attribute (sext in the first one, zext in the second). Also note
740 that the attribute for the function result (zext) comes immediately after the
741 argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]742
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]743 <p>Currently, only the following parameter attributes are defined:</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]744 <dl>
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]745 <dt><tt>zext</tt></dt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]746 <dd>This indicates that the parameter should be zero extended just before
747 a call to this function.</dd>
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]748 <dt><tt>sext</tt></dt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]749 <dd>This indicates that the parameter should be sign extended just before
750 a call to this function.</dd>
Anton Korobeynikov34d6dea2007-01-28 14:30:45 +0000[diff] [blame]751 <dt><tt>inreg</tt></dt>
752 <dd>This indicates that the parameter should be placed in register (if
Anton Korobeynikov66a8c8c2007-01-28 15:27:21 +0000[diff] [blame]753 possible) during assembling function call. Support for this attribute is
754 target-specific</dd>
Anton Korobeynikov34d6dea2007-01-28 14:30:45 +0000[diff] [blame]755 <dt><tt>sret</tt></dt>
Anton Korobeynikov66a8c8c2007-01-28 15:27:21 +0000[diff] [blame]756 <dd>This indicates that the parameter specifies the address of a structure
Reid Spencer67606122007-03-22 02:02:11 +0000[diff] [blame]757 that is the return value of the function in the source program.</dd>
Reid Spencer2dc52012007-03-22 02:18:56 +0000[diff] [blame]758 <dt><tt>noreturn</tt></dt>
759 <dd>This function attribute indicates that the function never returns. This
760 indicates to LLVM that every call to this function should be treated as if
761 an <tt>unreachable</tt> instruction immediately followed the call.</dd>
Reid Spencer67606122007-03-22 02:02:11 +0000[diff] [blame]762 <dt><tt>nounwind</tt></dt>
763 <dd>This function attribute indicates that the function type does not use
764 the unwind instruction and does not allow stack unwinding to propagate
765 through it.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]766 </dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]767
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]768</div>
769
770<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]771<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]772 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]773</div>
774
775<div class="doc_text">
776<p>
777Modules may contain "module-level inline asm" blocks, which corresponds to the
778GCC "file scope inline asm" blocks. These blocks are internally concatenated by
779LLVM and treated as a single unit, but may be separated in the .ll file if
780desired. The syntax is very simple:
781</p>
782
783<div class="doc_code"><pre>
Chris Lattner52599e12006-01-24 00:37:20 +0000[diff] [blame]784 module asm "inline asm code goes here"
785 module asm "more can go here"
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]786</pre></div>
787
788<p>The strings can contain any character by escaping non-printable characters.
789 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
790 for the number.
791</p>
792
793<p>
794 The inline asm code is simply printed to the machine code .s file when
795 assembly code is generated.
796</p>
797</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]798
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]799<!-- ======================================================================= -->
800<div class="doc_subsection">
801 <a name="datalayout">Data Layout</a>
802</div>
803
804<div class="doc_text">
805<p>A module may specify a target specific data layout string that specifies how
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]806data is to be laid out in memory. The syntax for the data layout is simply:</p>
807<pre> target datalayout = "<i>layout specification</i>"</pre>
808<p>The <i>layout specification</i> consists of a list of specifications
809separated by the minus sign character ('-'). Each specification starts with a
810letter and may include other information after the letter to define some
811aspect of the data layout. The specifications accepted are as follows: </p>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]812<dl>
813 <dt><tt>E</tt></dt>
814 <dd>Specifies that the target lays out data in big-endian form. That is, the
815 bits with the most significance have the lowest address location.</dd>
816 <dt><tt>e</tt></dt>
817 <dd>Specifies that hte target lays out data in little-endian form. That is,
818 the bits with the least significance have the lowest address location.</dd>
819 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
820 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
821 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
822 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
823 too.</dd>
824 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
825 <dd>This specifies the alignment for an integer type of a given bit
826 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
827 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
828 <dd>This specifies the alignment for a vector type of a given bit
829 <i>size</i>.</dd>
830 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
831 <dd>This specifies the alignment for a floating point type of a given bit
832 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
833 (double).</dd>
834 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
835 <dd>This specifies the alignment for an aggregate type of a given bit
836 <i>size</i>.</dd>
837</dl>
838<p>When constructing the data layout for a given target, LLVM starts with a
839default set of specifications which are then (possibly) overriden by the
840specifications in the <tt>datalayout</tt> keyword. The default specifications
841are given in this list:</p>
842<ul>
843 <li><tt>E</tt> - big endian</li>
844 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
845 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
846 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
847 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
848 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
849 <li><tt>i64:32:64</tt> - i64 has abi alignment of 32-bits but preferred
850 alignment of 64-bits</li>
851 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
852 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
853 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
854 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
855 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
856</ul>
857<p>When llvm is determining the alignment for a given type, it uses the
858following rules:
859<ol>
860 <li>If the type sought is an exact match for one of the specifications, that
861 specification is used.</li>
862 <li>If no match is found, and the type sought is an integer type, then the
863 smallest integer type that is larger than the bitwidth of the sought type is
864 used. If none of the specifications are larger than the bitwidth then the the
865 largest integer type is used. For example, given the default specifications
866 above, the i7 type will use the alignment of i8 (next largest) while both
867 i65 and i256 will use the alignment of i64 (largest specified).</li>
868 <li>If no match is found, and the type sought is a vector type, then the
869 largest vector type that is smaller than the sought vector type will be used
870 as a fall back. This happens because <128 x double> can be implemented in
871 terms of 64 <2 x double>, for example.</li>
872</ol>
873</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]874
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]875<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]876<div class="doc_section"> <a name="typesystem">Type System</a> </div>
877<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]878
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]879<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]880
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]881<p>The LLVM type system is one of the most important features of the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]882intermediate representation. Being typed enables a number of
883optimizations to be performed on the IR directly, without having to do
884extra analyses on the side before the transformation. A strong type
885system makes it easier to read the generated code and enables novel
886analyses and transformations that are not feasible to perform on normal
887three address code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]888
889</div>
890
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]891<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]892<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]893<div class="doc_text">
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]894<p>The primitive types are the fundamental building blocks of the LLVM
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]895system. The current set of primitive types is as follows:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]896
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]897<table class="layout">
898 <tr class="layout">
899 <td class="left">
900 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]901 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]902 <tr><th>Type</th><th>Description</th></tr>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]903 <tr><td><tt><a name="t_void">void</a></tt></td><td>No value</td></tr>
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]904 <tr><td><tt>i8</tt></td><td>8-bit value</td></tr>
905 <tr><td><tt>i32</tt></td><td>32-bit value</td></tr>
Misha Brukmancfa87bc2005-04-22 18:02:52 +0000[diff] [blame]906 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]907 <tr><td><tt>label</tt></td><td>Branch destination</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]908 </tbody>
909 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]910 </td>
911 <td class="right">
912 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]913 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]914 <tr><th>Type</th><th>Description</th></tr>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]915 <tr><td><tt>i1</tt></td><td>True or False value</td></tr>
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]916 <tr><td><tt>i16</tt></td><td>16-bit value</td></tr>
917 <tr><td><tt>i64</tt></td><td>64-bit value</td></tr>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]918 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]919 </tbody>
920 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]921 </td>
922 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]923</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]924</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]925
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]926<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]927<div class="doc_subsubsection"> <a name="t_classifications">Type
928Classifications</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]929<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]930<p>These different primitive types fall into a few useful
931classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]932
933<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]934 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]935 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]936 <tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]937 <td><a name="t_integer">integer</a></td>
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]938 <td><tt>i1, i8, i16, i32, i64</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]939 </tr>
940 <tr>
941 <td><a name="t_floating">floating point</a></td>
942 <td><tt>float, double</tt></td>
943 </tr>
944 <tr>
945 <td><a name="t_firstclass">first class</a></td>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]946 <td><tt>i1, i8, i16, i32, i64, float, double, <br/>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]947 <a href="#t_pointer">pointer</a>,<a href="#t_vector">vector</a></tt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]948 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]949 </tr>
950 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]951</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]952
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]953<p>The <a href="#t_firstclass">first class</a> types are perhaps the
954most important. Values of these types are the only ones which can be
955produced by instructions, passed as arguments, or used as operands to
956instructions. This means that all structures and arrays must be
957manipulated either by pointer or by component.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]958</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]959
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]960<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]961<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]962
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]963<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]964
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]965<p>The real power in LLVM comes from the derived types in the system.
966This is what allows a programmer to represent arrays, functions,
967pointers, and other useful types. Note that these derived types may be
968recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]969
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]970</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]971
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]972<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]973<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]974
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]975<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]976
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]977<h5>Overview:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]978
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]979<p>The array type is a very simple derived type that arranges elements
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]980sequentially in memory. The array type requires a size (number of
981elements) and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]982
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]983<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]984
985<pre>
986 [&lt;# elements&gt; x &lt;elementtype&gt;]
987</pre>
988
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]989<p>The number of elements is a constant integer value; elementtype may
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]990be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]991
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]992<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]993<table class="layout">
994 <tr class="layout">
995 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]996 <tt>[40 x i32 ]</tt><br/>
997 <tt>[41 x i32 ]</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]998 <tt>[40 x i8]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]999 </td>
1000 <td class="left">
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1001 Array of 40 32-bit integer values.<br/>
1002 Array of 41 32-bit integer values.<br/>
1003 Array of 40 8-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1004 </td>
1005 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1006</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1007<p>Here are some examples of multidimensional arrays:</p>
1008<table class="layout">
1009 <tr class="layout">
1010 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1011 <tt>[3 x [4 x i32]]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1012 <tt>[12 x [10 x float]]</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1013 <tt>[2 x [3 x [4 x i16]]]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1014 </td>
1015 <td class="left">
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1016 3x4 array of 32-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1017 12x10 array of single precision floating point values.<br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1018 2x3x4 array of 16-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1019 </td>
1020 </tr>
1021</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1022
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1023<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1024length array. Normally, accesses past the end of an array are undefined in
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1025LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1026As a special case, however, zero length arrays are recognized to be variable
1027length. This allows implementation of 'pascal style arrays' with the LLVM
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1028type "{ i32, [0 x float]}", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1029
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1030</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1031
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1032<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1033<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1034<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1035<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1036<p>The function type can be thought of as a function signature. It
1037consists of a return type and a list of formal parameter types.
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]1038Function types are usually used to build virtual function tables
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1039(which are structures of pointers to functions), for indirect function
1040calls, and when defining a function.</p>
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]1041<p>
1042The return type of a function type cannot be an aggregate type.
1043</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1044<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1045<pre> &lt;returntype&gt; (&lt;parameter list&gt;)<br></pre>
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1046<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]1047specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1048which indicates that the function takes a variable number of arguments.
1049Variable argument functions can access their arguments with the <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1050 href="#int_varargs">variable argument handling intrinsic</a> functions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1051<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1052<table class="layout">
1053 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1054 <td class="left"><tt>i32 (i32)</tt></td>
1055 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1056 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1057 </tr><tr class="layout">
Reid Spencer7bf214d2007-01-15 18:28:34 +0000[diff] [blame]1058 <td class="left"><tt>float&nbsp;(i16&nbsp;sext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1059 </tt></td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1060 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1061 an <tt>i16</tt> that should be sign extended and a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1062 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1063 <tt>float</tt>.
1064 </td>
1065 </tr><tr class="layout">
1066 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1067 <td class="left">A vararg function that takes at least one
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1068 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1069 which returns an integer. This is the signature for <tt>printf</tt> in
1070 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1071 </td>
1072 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1073</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1074
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1075</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1076<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1077<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1078<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1079<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1080<p>The structure type is used to represent a collection of data members
1081together in memory. The packing of the field types is defined to match
1082the ABI of the underlying processor. The elements of a structure may
1083be any type that has a size.</p>
1084<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1085and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1086field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1087instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1088<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1089<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1090<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1091<table class="layout">
1092 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1093 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1094 <td class="left">A triple of three <tt>i32</tt> values</td>
1095 </tr><tr class="layout">
1096 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1097 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1098 second element is a <a href="#t_pointer">pointer</a> to a
1099 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1100 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1101 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1102</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1103</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1104
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1105<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1106<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1107</div>
1108<div class="doc_text">
1109<h5>Overview:</h5>
1110<p>The packed structure type is used to represent a collection of data members
1111together in memory. There is no padding between fields. Further, the alignment
1112of a packed structure is 1 byte. The elements of a packed structure may
1113be any type that has a size.</p>
1114<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1115and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1116field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1117instruction.</p>
1118<h5>Syntax:</h5>
1119<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1120<h5>Examples:</h5>
1121<table class="layout">
1122 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1123 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1124 <td class="left">A triple of three <tt>i32</tt> values</td>
1125 </tr><tr class="layout">
1126 <td class="left"><tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}&nbsp;&gt;</tt></td>
1127 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1128 second element is a <a href="#t_pointer">pointer</a> to a
1129 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1130 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1131 </tr>
1132</table>
1133</div>
1134
1135<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1136<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1137<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1138<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1139<p>As in many languages, the pointer type represents a pointer or
1140reference to another object, which must live in memory.</p>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1141<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1142<pre> &lt;type&gt; *<br></pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1143<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1144<table class="layout">
1145 <tr class="layout">
1146 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1147 <tt>[4x i32]*</tt><br/>
1148 <tt>i32 (i32 *) *</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1149 </td>
1150 <td class="left">
1151 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]1152 four <tt>i32</tt> values<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1153 A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1154 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
1155 <tt>i32</tt>.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1156 </td>
1157 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1158</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1159</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1160
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1161<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1162<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1163<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1164
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1165<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1166
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1167<p>A vector type is a simple derived type that represents a vector
1168of elements. Vector types are used when multiple primitive data
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1169are operated in parallel using a single instruction (SIMD).
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1170A vector type requires a size (number of
Chris Lattnerb8d172f2005-11-10 01:44:22 +0000[diff] [blame]1171elements) and an underlying primitive data type. Vectors must have a power
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1172of two length (1, 2, 4, 8, 16 ...). Vector types are
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1173considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1174
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1175<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1176
1177<pre>
1178 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1179</pre>
1180
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1181<p>The number of elements is a constant integer value; elementtype may
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]1182be any integer or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1183
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1184<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1185
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1186<table class="layout">
1187 <tr class="layout">
1188 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1189 <tt>&lt;4 x i32&gt;</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1190 <tt>&lt;8 x float&gt;</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1191 <tt>&lt;2 x i64&gt;</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1192 </td>
1193 <td class="left">
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1194 Vector of 4 32-bit integer values.<br/>
1195 Vector of 8 floating-point values.<br/>
1196 Vector of 2 64-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1197 </td>
1198 </tr>
1199</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1200</div>
1201
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1202<!-- _______________________________________________________________________ -->
1203<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1204<div class="doc_text">
1205
1206<h5>Overview:</h5>
1207
1208<p>Opaque types are used to represent unknown types in the system. This
1209corresponds (for example) to the C notion of a foward declared structure type.
1210In LLVM, opaque types can eventually be resolved to any type (not just a
1211structure type).</p>
1212
1213<h5>Syntax:</h5>
1214
1215<pre>
1216 opaque
1217</pre>
1218
1219<h5>Examples:</h5>
1220
1221<table class="layout">
1222 <tr class="layout">
1223 <td class="left">
1224 <tt>opaque</tt>
1225 </td>
1226 <td class="left">
1227 An opaque type.<br/>
1228 </td>
1229 </tr>
1230</table>
1231</div>
1232
1233
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1234<!-- *********************************************************************** -->
1235<div class="doc_section"> <a name="constants">Constants</a> </div>
1236<!-- *********************************************************************** -->
1237
1238<div class="doc_text">
1239
1240<p>LLVM has several different basic types of constants. This section describes
1241them all and their syntax.</p>
1242
1243</div>
1244
1245<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1246<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1247
1248<div class="doc_text">
1249
1250<dl>
1251 <dt><b>Boolean constants</b></dt>
1252
1253 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1254 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1255 </dd>
1256
1257 <dt><b>Integer constants</b></dt>
1258
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1259 <dd>Standard integers (such as '4') are constants of the <a
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1260 href="#t_integer">integer</a> type. Negative numbers may be used with
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1261 integer types.
1262 </dd>
1263
1264 <dt><b>Floating point constants</b></dt>
1265
1266 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1267 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1268 notation (see below). Floating point constants must have a <a
1269 href="#t_floating">floating point</a> type. </dd>
1270
1271 <dt><b>Null pointer constants</b></dt>
1272
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1273 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1274 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1275
1276</dl>
1277
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1278<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1279of floating point constants. For example, the form '<tt>double
12800x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
12814.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1282(and the only time that they are generated by the disassembler) is when a
1283floating point constant must be emitted but it cannot be represented as a
1284decimal floating point number. For example, NaN's, infinities, and other
1285special values are represented in their IEEE hexadecimal format so that
1286assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1287
1288</div>
1289
1290<!-- ======================================================================= -->
1291<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1292</div>
1293
1294<div class="doc_text">
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1295<p>Aggregate constants arise from aggregation of simple constants
1296and smaller aggregate constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1297
1298<dl>
1299 <dt><b>Structure constants</b></dt>
1300
1301 <dd>Structure constants are represented with notation similar to structure
1302 type definitions (a comma separated list of elements, surrounded by braces
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1303 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* %G }</tt>",
1304 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]1305 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1306 types of elements must match those specified by the type.
1307 </dd>
1308
1309 <dt><b>Array constants</b></dt>
1310
1311 <dd>Array constants are represented with notation similar to array type
1312 definitions (a comma separated list of elements, surrounded by square brackets
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1313 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1314 constants must have <a href="#t_array">array type</a>, and the number and
1315 types of elements must match those specified by the type.
1316 </dd>
1317
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1318 <dt><b>Vector constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1319
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1320 <dd>Vector constants are represented with notation similar to vector type
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1321 definitions (a comma separated list of elements, surrounded by
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1322 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32 42,
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1323 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1324 href="#t_vector">vector type</a>, and the number and types of elements must
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1325 match those specified by the type.
1326 </dd>
1327
1328 <dt><b>Zero initialization</b></dt>
1329
1330 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1331 value to zero of <em>any</em> type, including scalar and aggregate types.
1332 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]1333 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1334 initializers.
1335 </dd>
1336</dl>
1337
1338</div>
1339
1340<!-- ======================================================================= -->
1341<div class="doc_subsection">
1342 <a name="globalconstants">Global Variable and Function Addresses</a>
1343</div>
1344
1345<div class="doc_text">
1346
1347<p>The addresses of <a href="#globalvars">global variables</a> and <a
1348href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1349constants. These constants are explicitly referenced when the <a
1350href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1351href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1352file:</p>
1353
1354<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1355 %X = global i32 17
1356 %Y = global i32 42
1357 %Z = global [2 x i32*] [ i32* %X, i32* %Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1358</pre>
1359
1360</div>
1361
1362<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1363<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1364<div class="doc_text">
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1365 <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]1366 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1367 a constant is permitted.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1368
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1369 <p>Undefined values indicate to the compiler that the program is well defined
1370 no matter what value is used, giving the compiler more freedom to optimize.
1371 </p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1372</div>
1373
1374<!-- ======================================================================= -->
1375<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1376</div>
1377
1378<div class="doc_text">
1379
1380<p>Constant expressions are used to allow expressions involving other constants
1381to be used as constants. Constant expressions may be of any <a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1382href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1383that does not have side effects (e.g. load and call are not supported). The
1384following is the syntax for constant expressions:</p>
1385
1386<dl>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1387 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1388 <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]1389 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1390
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1391 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1392 <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]1393 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]1394
1395 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1396 <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]1397 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]1398
1399 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1400 <dd>Truncate a floating point constant to another floating point type. The
1401 size of CST must be larger than the size of TYPE. Both types must be
1402 floating point.</dd>
1403
1404 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1405 <dd>Floating point extend a constant to another type. The size of CST must be
1406 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1407
1408 <dt><b><tt>fp2uint ( CST to TYPE )</tt></b></dt>
1409 <dd>Convert a floating point constant to the corresponding unsigned integer
1410 constant. TYPE must be an integer type. CST must be floating point. If the
1411 value won't fit in the integer type, the results are undefined.</dd>
1412
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1413 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1414 <dd>Convert a floating point constant to the corresponding signed integer
1415 constant. TYPE must be an integer type. CST must be floating point. If the
1416 value won't fit in the integer type, the results are undefined.</dd>
1417
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1418 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1419 <dd>Convert an unsigned integer constant to the corresponding floating point
1420 constant. TYPE must be floating point. CST must be of integer type. If the
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]1421 value won't fit in the floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1422
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1423 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1424 <dd>Convert a signed integer constant to the corresponding floating point
1425 constant. TYPE must be floating point. CST must be of integer type. If the
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]1426 value won't fit in the floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1427
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]1428 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1429 <dd>Convert a pointer typed constant to the corresponding integer constant
1430 TYPE must be an integer type. CST must be of pointer type. The CST value is
1431 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1432
1433 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1434 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1435 pointer type. CST must be of integer type. The CST value is zero extended,
1436 truncated, or unchanged to make it fit in a pointer size. This one is
1437 <i>really</i> dangerous!</dd>
1438
1439 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1440 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1441 identical (same number of bits). The conversion is done as if the CST value
1442 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]1443 with this operator, just the type. This can be used for conversion of
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1444 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]1445 pointers it is only valid to cast to another pointer type.
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1446 </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1447
1448 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1449
1450 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1451 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1452 instruction, the index list may have zero or more indexes, which are required
1453 to make sense for the type of "CSTPTR".</dd>
1454
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1455 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1456
1457 <dd>Perform the <a href="#i_select">select operation</a> on
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1458 constants.</dd>
1459
1460 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1461 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1462
1463 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1464 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1465
1466 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1467
1468 <dd>Perform the <a href="#i_extractelement">extractelement
1469 operation</a> on constants.
1470
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1471 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1472
1473 <dd>Perform the <a href="#i_insertelement">insertelement
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1474 operation</a> on constants.</dd>
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1475
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1476
1477 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1478
1479 <dd>Perform the <a href="#i_shufflevector">shufflevector
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1480 operation</a> on constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1481
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1482 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1483
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1484 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1485 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1486 binary</a> operations. The constraints on operands are the same as those for
1487 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1488 values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1489</dl>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1490</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]1491
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1492<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1493<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1494<!-- *********************************************************************** -->
1495
1496<!-- ======================================================================= -->
1497<div class="doc_subsection">
1498<a name="inlineasm">Inline Assembler Expressions</a>
1499</div>
1500
1501<div class="doc_text">
1502
1503<p>
1504LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1505Module-Level Inline Assembly</a>) through the use of a special value. This
1506value represents the inline assembler as a string (containing the instructions
1507to emit), a list of operand constraints (stored as a string), and a flag that
1508indicates whether or not the inline asm expression has side effects. An example
1509inline assembler expression is:
1510</p>
1511
1512<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1513 i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1514</pre>
1515
1516<p>
1517Inline assembler expressions may <b>only</b> be used as the callee operand of
1518a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1519</p>
1520
1521<pre>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]1522 %X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1523</pre>
1524
1525<p>
1526Inline asms with side effects not visible in the constraint list must be marked
1527as having side effects. This is done through the use of the
1528'<tt>sideeffect</tt>' keyword, like so:
1529</p>
1530
1531<pre>
1532 call void asm sideeffect "eieio", ""()
1533</pre>
1534
1535<p>TODO: The format of the asm and constraints string still need to be
1536documented here. Constraints on what can be done (e.g. duplication, moving, etc
1537need to be documented).
1538</p>
1539
1540</div>
1541
1542<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1543<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1544<!-- *********************************************************************** -->
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>The LLVM instruction set consists of several different
1549classifications of instructions: <a href="#terminators">terminator
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1550instructions</a>, <a href="#binaryops">binary instructions</a>,
1551<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1552 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1553instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1554
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1555</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1556
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1557<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1558<div class="doc_subsection"> <a name="terminators">Terminator
1559Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1560
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1561<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1562
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1563<p>As mentioned <a href="#functionstructure">previously</a>, every
1564basic block in a program ends with a "Terminator" instruction, which
1565indicates which block should be executed after the current block is
1566finished. These terminator instructions typically yield a '<tt>void</tt>'
1567value: they produce control flow, not values (the one exception being
1568the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1569<p>There are six different terminator instructions: the '<a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1570 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1571instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1572the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1573 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1574 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1575
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1576</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1577
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1578<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1579<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1580Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1581<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1582<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1583<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]1584 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1585</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1586<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1587<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1588value) from a function back to the caller.</p>
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]1589<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1590returns a value and then causes control flow, and one that just causes
1591control flow to occur.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1592<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1593<p>The '<tt>ret</tt>' instruction may return any '<a
1594 href="#t_firstclass">first class</a>' type. Notice that a function is
1595not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
1596instruction inside of the function that returns a value that does not
1597match the return type of the function.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1598<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1599<p>When the '<tt>ret</tt>' instruction is executed, control flow
1600returns back to the calling function's context. If the caller is a "<a
John Criswellfa081872004-06-25 15:16:57 +0000[diff] [blame]1601 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1602the instruction after the call. If the caller was an "<a
1603 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1604at the beginning of the "normal" destination block. If the instruction
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1605returns a value, that value shall set the call or invoke instruction's
1606return value.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1607<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1608<pre> ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1609 ret void <i>; Return from a void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1610</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1611</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1612<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1613<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1614<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1615<h5>Syntax:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1616<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]1617</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1618<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1619<p>The '<tt>br</tt>' instruction is used to cause control flow to
1620transfer to a different basic block in the current function. There are
1621two forms of this instruction, corresponding to a conditional branch
1622and an unconditional branch.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1623<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1624<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1625single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1626unconditional form of the '<tt>br</tt>' instruction takes a single
1627'<tt>label</tt>' value as a target.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1628<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1629<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1630argument is evaluated. If the value is <tt>true</tt>, control flows
1631to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1632control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1633<h5>Example:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1634<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]1635 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]1636</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1637<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1638<div class="doc_subsubsection">
1639 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1640</div>
1641
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1642<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1643<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1644
1645<pre>
1646 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1647</pre>
1648
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1649<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1650
1651<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1652several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1653instruction, allowing a branch to occur to one of many possible
1654destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1655
1656
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1657<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1658
1659<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1660comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1661an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1662table is not allowed to contain duplicate constant entries.</p>
1663
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1664<h5>Semantics:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1665
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1666<p>The <tt>switch</tt> instruction specifies a table of values and
1667destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1668table is searched for the given value. If the value is found, control flow is
1669transfered to the corresponding destination; otherwise, control flow is
1670transfered to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1671
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1672<h5>Implementation:</h5>
1673
1674<p>Depending on properties of the target machine and the particular
1675<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1676ways. For example, it could be generated as a series of chained conditional
1677branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1678
1679<h5>Example:</h5>
1680
1681<pre>
1682 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1683 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1684 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1685
1686 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1687 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1688
1689 <i>; Implement a jump table:</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1690 switch i32 %val, label %otherwise [ i32 0, label %onzero
1691 i32 1, label %onone
1692 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1693</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1694</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1695
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1696<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1697<div class="doc_subsubsection">
1698 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1699</div>
1700
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1701<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1702
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1703<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1704
1705<pre>
1706 &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]1707 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1708</pre>
1709
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1710<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1711
1712<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1713function, with the possibility of control flow transfer to either the
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1714'<tt>normal</tt>' label or the
1715'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1716"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1717"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1718href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
1719continued at the dynamically nearest "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1720
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1721<h5>Arguments:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1722
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1723<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1724
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1725<ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1726 <li>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]1727 The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1728 convention</a> the call should use. If none is specified, the call defaults
1729 to using C calling conventions.
1730 </li>
1731 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1732 function value being invoked. In most cases, this is a direct function
1733 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1734 an arbitrary pointer to function value.
1735 </li>
1736
1737 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1738 function to be invoked. </li>
1739
1740 <li>'<tt>function args</tt>': argument list whose types match the function
1741 signature argument types. If the function signature indicates the function
1742 accepts a variable number of arguments, the extra arguments can be
1743 specified. </li>
1744
1745 <li>'<tt>normal label</tt>': the label reached when the called function
1746 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1747
1748 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1749 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1750
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1751</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1752
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1753<h5>Semantics:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1754
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1755<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1756href="#i_call">call</a></tt>' instruction in most regards. The primary
1757difference is that it establishes an association with a label, which is used by
1758the runtime library to unwind the stack.</p>
1759
1760<p>This instruction is used in languages with destructors to ensure that proper
1761cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1762exception. Additionally, this is important for implementation of
1763'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1764
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1765<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1766<pre>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1767 %retval = invoke i32 %Test(i32 15) to label %Continue
1768 unwind label %TestCleanup <i>; {i32}:retval set</i>
1769 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Test(i32 15) to label %Continue
1770 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1771</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1772</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1773
1774
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1775<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1776
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1777<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1778Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1779
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1780<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1781
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1782<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1783<pre>
1784 unwind
1785</pre>
1786
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1787<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1788
1789<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
1790at the first callee in the dynamic call stack which used an <a
1791href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
1792primarily used to implement exception handling.</p>
1793
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1794<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1795
1796<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
1797immediately halt. The dynamic call stack is then searched for the first <a
1798href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
1799execution continues at the "exceptional" destination block specified by the
1800<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
1801dynamic call chain, undefined behavior results.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1802</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1803
1804<!-- _______________________________________________________________________ -->
1805
1806<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
1807Instruction</a> </div>
1808
1809<div class="doc_text">
1810
1811<h5>Syntax:</h5>
1812<pre>
1813 unreachable
1814</pre>
1815
1816<h5>Overview:</h5>
1817
1818<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
1819instruction is used to inform the optimizer that a particular portion of the
1820code is not reachable. This can be used to indicate that the code after a
1821no-return function cannot be reached, and other facts.</p>
1822
1823<h5>Semantics:</h5>
1824
1825<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
1826</div>
1827
1828
1829
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1830<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1831<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1832<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1833<p>Binary operators are used to do most of the computation in a
1834program. They require two operands, execute an operation on them, and
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1835produce a single value. The operands might represent
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1836multiple 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]1837The result value of a binary operator is not
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1838necessarily the same type as its operands.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1839<p>There are several different binary operators:</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1840</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1841<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1842<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
1843Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1844<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1845<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1846<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]1847</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1848<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1849<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1850<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1851<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1852 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1853 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]1854Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1855<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1856<p>The value produced is the integer or floating point sum of the two
1857operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1858<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1859<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]1860</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1861</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1862<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1863<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
1864Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1865<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1866<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1867<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]1868</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1869<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1870<p>The '<tt>sub</tt>' instruction returns the difference of its two
1871operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1872<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
1873instruction present in most other intermediate representations.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1874<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1875<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1876 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1877values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1878This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1879Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1880<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1881<p>The value produced is the integer or floating point difference of
1882the two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1883<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1884<pre> &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
1885 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1886</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1887</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1888<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1889<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
1890Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1891<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1892<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1893<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]1894</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1895<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1896<p>The '<tt>mul</tt>' instruction returns the product of its two
1897operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1898<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1899<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1900 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1901values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1902This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1903Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1904<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1905<p>The value produced is the integer or floating point product of the
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1906two operands.</p>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1907<p>Because the operands are the same width, the result of an integer
1908multiplication is the same whether the operands should be deemed unsigned or
1909signed.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1910<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1911<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]1912</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1913</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1914<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1915<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
1916</a></div>
1917<div class="doc_text">
1918<h5>Syntax:</h5>
1919<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1920</pre>
1921<h5>Overview:</h5>
1922<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
1923operands.</p>
1924<h5>Arguments:</h5>
1925<p>The two arguments to the '<tt>udiv</tt>' instruction must be
1926<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1927types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1928of the values in which case the elements must be integers.</p>
1929<h5>Semantics:</h5>
1930<p>The value produced is the unsigned integer quotient of the two operands. This
1931instruction always performs an unsigned division operation, regardless of
1932whether the arguments are unsigned or not.</p>
1933<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1934<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]1935</pre>
1936</div>
1937<!-- _______________________________________________________________________ -->
1938<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
1939</a> </div>
1940<div class="doc_text">
1941<h5>Syntax:</h5>
1942<pre> &lt;result&gt; = sdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1943</pre>
1944<h5>Overview:</h5>
1945<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
1946operands.</p>
1947<h5>Arguments:</h5>
1948<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
1949<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1950types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1951of the values in which case the elements must be integers.</p>
1952<h5>Semantics:</h5>
1953<p>The value produced is the signed integer quotient of the two operands. This
1954instruction always performs a signed division operation, regardless of whether
1955the arguments are signed or not.</p>
1956<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1957<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]1958</pre>
1959</div>
1960<!-- _______________________________________________________________________ -->
1961<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1962Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1963<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1964<h5>Syntax:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1965<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]1966</pre>
1967<h5>Overview:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1968<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1969operands.</p>
1970<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1971<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1972<a href="#t_floating">floating point</a> values. Both arguments must have
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1973identical types. This instruction can also take <a href="#t_vector">vector</a>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1974versions of floating point values.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1975<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1976<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1977<h5>Example:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1978<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]1979</pre>
1980</div>
1981<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1982<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
1983</div>
1984<div class="doc_text">
1985<h5>Syntax:</h5>
1986<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1987</pre>
1988<h5>Overview:</h5>
1989<p>The '<tt>urem</tt>' instruction returns the remainder from the
1990unsigned division of its two arguments.</p>
1991<h5>Arguments:</h5>
1992<p>The two arguments to the '<tt>urem</tt>' instruction must be
1993<a href="#t_integer">integer</a> values. Both arguments must have identical
1994types.</p>
1995<h5>Semantics:</h5>
1996<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
1997This instruction always performs an unsigned division to get the remainder,
1998regardless of whether the arguments are unsigned or not.</p>
1999<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2000<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]2001</pre>
2002
2003</div>
2004<!-- _______________________________________________________________________ -->
2005<div class="doc_subsubsection"> <a name="i_srem">'<tt>srem</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2006Instruction</a> </div>
2007<div class="doc_text">
2008<h5>Syntax:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2009<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]2010</pre>
2011<h5>Overview:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2012<p>The '<tt>srem</tt>' instruction returns the remainder from the
2013signed division of its two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2014<h5>Arguments:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2015<p>The two arguments to the '<tt>srem</tt>' instruction must be
2016<a href="#t_integer">integer</a> values. Both arguments must have identical
2017types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2018<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2019<p>This instruction returns the <i>remainder</i> of a division (where the result
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2020has the same sign as the dividend, <tt>var1</tt>), not the <i>modulo</i>
2021operator (where the result has the same sign as the divisor, <tt>var2</tt>) of
2022a value. For more information about the difference, see <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2023 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2024Math Forum</a>. For a table of how this is implemented in various languages,
Reid Spencer64f5c6c2007-03-24 22:40:44 +0000[diff] [blame]2025please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2026Wikipedia: modulo operation</a>.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2027<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2028<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]2029</pre>
2030
2031</div>
2032<!-- _______________________________________________________________________ -->
2033<div class="doc_subsubsection"> <a name="i_frem">'<tt>frem</tt>'
2034Instruction</a> </div>
2035<div class="doc_text">
2036<h5>Syntax:</h5>
2037<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2038</pre>
2039<h5>Overview:</h5>
2040<p>The '<tt>frem</tt>' instruction returns the remainder from the
2041division of its two operands.</p>
2042<h5>Arguments:</h5>
2043<p>The two arguments to the '<tt>frem</tt>' instruction must be
2044<a href="#t_floating">floating point</a> values. Both arguments must have
2045identical types.</p>
2046<h5>Semantics:</h5>
2047<p>This instruction returns the <i>remainder</i> of a division.</p>
2048<h5>Example:</h5>
2049<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]2050</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2051</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]2052
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]2053<!-- ======================================================================= -->
2054<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2055Operations</a> </div>
2056<div class="doc_text">
2057<p>Bitwise binary operators are used to do various forms of
2058bit-twiddling in a program. They are generally very efficient
2059instructions and can commonly be strength reduced from other
2060instructions. They require two operands, execute an operation on them,
2061and produce a single value. The resulting value of the bitwise binary
2062operators is always the same type as its first operand.</p>
2063</div>
2064
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2065<!-- _______________________________________________________________________ -->
2066<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2067Instruction</a> </div>
2068<div class="doc_text">
2069<h5>Syntax:</h5>
2070<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2071</pre>
2072<h5>Overview:</h5>
2073<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2074the left a specified number of bits.</p>
2075<h5>Arguments:</h5>
2076<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
2077 href="#t_integer">integer</a> type.</p>
2078<h5>Semantics:</h5>
2079<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>.</p>
2080<h5>Example:</h5><pre>
2081 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2082 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2083 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
2084</pre>
2085</div>
2086<!-- _______________________________________________________________________ -->
2087<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2088Instruction</a> </div>
2089<div class="doc_text">
2090<h5>Syntax:</h5>
2091<pre> &lt;result&gt; = lshr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2092</pre>
2093
2094<h5>Overview:</h5>
2095<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2096operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2097
2098<h5>Arguments:</h5>
2099<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
2100<a href="#t_integer">integer</a> type.</p>
2101
2102<h5>Semantics:</h5>
2103<p>This instruction always performs a logical shift right operation. The most
2104significant bits of the result will be filled with zero bits after the
2105shift.</p>
2106
2107<h5>Example:</h5>
2108<pre>
2109 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2110 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2111 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2112 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
2113</pre>
2114</div>
2115
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]2116<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2117<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2118Instruction</a> </div>
2119<div class="doc_text">
2120
2121<h5>Syntax:</h5>
2122<pre> &lt;result&gt; = ashr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2123</pre>
2124
2125<h5>Overview:</h5>
2126<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2127operand shifted to the right a specified number of bits with sign extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2128
2129<h5>Arguments:</h5>
2130<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
2131<a href="#t_integer">integer</a> type.</p>
2132
2133<h5>Semantics:</h5>
2134<p>This instruction always performs an arithmetic shift right operation,
2135The most significant bits of the result will be filled with the sign bit
2136of <tt>var1</tt>.</p>
2137
2138<h5>Example:</h5>
2139<pre>
2140 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2141 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2142 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2143 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
2144</pre>
2145</div>
2146
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2147<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2148<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2149Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2150<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2151<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2152<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]2153</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2154<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2155<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2156its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2157<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2158<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2159 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2160identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2161<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2162<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2163<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2164<div style="align: center">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2165<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2166 <tbody>
2167 <tr>
2168 <td>In0</td>
2169 <td>In1</td>
2170 <td>Out</td>
2171 </tr>
2172 <tr>
2173 <td>0</td>
2174 <td>0</td>
2175 <td>0</td>
2176 </tr>
2177 <tr>
2178 <td>0</td>
2179 <td>1</td>
2180 <td>0</td>
2181 </tr>
2182 <tr>
2183 <td>1</td>
2184 <td>0</td>
2185 <td>0</td>
2186 </tr>
2187 <tr>
2188 <td>1</td>
2189 <td>1</td>
2190 <td>1</td>
2191 </tr>
2192 </tbody>
2193</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2194</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2195<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2196<pre> &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
2197 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2198 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2199</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2200</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2201<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2202<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2203<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2204<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2205<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]2206</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2207<h5>Overview:</h5>
2208<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2209or of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2210<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2211<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2212 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2213identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2214<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2215<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2216<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2217<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2218<table border="1" cellspacing="0" cellpadding="4">
2219 <tbody>
2220 <tr>
2221 <td>In0</td>
2222 <td>In1</td>
2223 <td>Out</td>
2224 </tr>
2225 <tr>
2226 <td>0</td>
2227 <td>0</td>
2228 <td>0</td>
2229 </tr>
2230 <tr>
2231 <td>0</td>
2232 <td>1</td>
2233 <td>1</td>
2234 </tr>
2235 <tr>
2236 <td>1</td>
2237 <td>0</td>
2238 <td>1</td>
2239 </tr>
2240 <tr>
2241 <td>1</td>
2242 <td>1</td>
2243 <td>1</td>
2244 </tr>
2245 </tbody>
2246</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2247</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2248<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2249<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2250 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2251 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2252</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2253</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2254<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2255<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2256Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2257<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2258<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2259<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]2260</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2261<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2262<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2263or of its two operands. The <tt>xor</tt> is used to implement the
2264"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2265<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2266<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2267 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2268identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2269<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2270<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2271<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2272<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2273<table border="1" cellspacing="0" cellpadding="4">
2274 <tbody>
2275 <tr>
2276 <td>In0</td>
2277 <td>In1</td>
2278 <td>Out</td>
2279 </tr>
2280 <tr>
2281 <td>0</td>
2282 <td>0</td>
2283 <td>0</td>
2284 </tr>
2285 <tr>
2286 <td>0</td>
2287 <td>1</td>
2288 <td>1</td>
2289 </tr>
2290 <tr>
2291 <td>1</td>
2292 <td>0</td>
2293 <td>1</td>
2294 </tr>
2295 <tr>
2296 <td>1</td>
2297 <td>1</td>
2298 <td>0</td>
2299 </tr>
2300 </tbody>
2301</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2302</div>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2303<p> </p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2304<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2305<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2306 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2307 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2308 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2309</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2310</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2311
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2312<!-- ======================================================================= -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2313<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2314 <a name="vectorops">Vector Operations</a>
2315</div>
2316
2317<div class="doc_text">
2318
2319<p>LLVM supports several instructions to represent vector operations in a
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2320target-independent manner. These instructions cover the element-access and
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2321vector-specific operations needed to process vectors effectively. While LLVM
2322does directly support these vector operations, many sophisticated algorithms
2323will want to use target-specific intrinsics to take full advantage of a specific
2324target.</p>
2325
2326</div>
2327
2328<!-- _______________________________________________________________________ -->
2329<div class="doc_subsubsection">
2330 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2331</div>
2332
2333<div class="doc_text">
2334
2335<h5>Syntax:</h5>
2336
2337<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2338 &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]2339</pre>
2340
2341<h5>Overview:</h5>
2342
2343<p>
2344The '<tt>extractelement</tt>' instruction extracts a single scalar
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2345element from a vector at a specified index.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2346</p>
2347
2348
2349<h5>Arguments:</h5>
2350
2351<p>
2352The first operand of an '<tt>extractelement</tt>' instruction is a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2353value of <a href="#t_vector">vector</a> type. The second operand is
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2354an index indicating the position from which to extract the element.
2355The index may be a variable.</p>
2356
2357<h5>Semantics:</h5>
2358
2359<p>
2360The result is a scalar of the same type as the element type of
2361<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2362<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2363results are undefined.
2364</p>
2365
2366<h5>Example:</h5>
2367
2368<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2369 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2370</pre>
2371</div>
2372
2373
2374<!-- _______________________________________________________________________ -->
2375<div class="doc_subsubsection">
2376 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2377</div>
2378
2379<div class="doc_text">
2380
2381<h5>Syntax:</h5>
2382
2383<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2384 &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]2385</pre>
2386
2387<h5>Overview:</h5>
2388
2389<p>
2390The '<tt>insertelement</tt>' instruction inserts a scalar
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2391element into a vector at a specified index.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2392</p>
2393
2394
2395<h5>Arguments:</h5>
2396
2397<p>
2398The first operand of an '<tt>insertelement</tt>' instruction is a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2399value of <a href="#t_vector">vector</a> type. The second operand is a
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2400scalar value whose type must equal the element type of the first
2401operand. The third operand is an index indicating the position at
2402which to insert the value. The index may be a variable.</p>
2403
2404<h5>Semantics:</h5>
2405
2406<p>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2407The result is a vector of the same type as <tt>val</tt>. Its
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2408element values are those of <tt>val</tt> except at position
2409<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2410exceeds the length of <tt>val</tt>, the results are undefined.
2411</p>
2412
2413<h5>Example:</h5>
2414
2415<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2416 %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]2417</pre>
2418</div>
2419
2420<!-- _______________________________________________________________________ -->
2421<div class="doc_subsubsection">
2422 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2423</div>
2424
2425<div class="doc_text">
2426
2427<h5>Syntax:</h5>
2428
2429<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2430 &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]2431</pre>
2432
2433<h5>Overview:</h5>
2434
2435<p>
2436The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2437from two input vectors, returning a vector of the same type.
2438</p>
2439
2440<h5>Arguments:</h5>
2441
2442<p>
2443The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2444with types that match each other and types that match the result of the
2445instruction. The third argument is a shuffle mask, which has the same number
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2446of elements as the other vector type, but whose element type is always 'i32'.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2447</p>
2448
2449<p>
2450The shuffle mask operand is required to be a constant vector with either
2451constant integer or undef values.
2452</p>
2453
2454<h5>Semantics:</h5>
2455
2456<p>
2457The elements of the two input vectors are numbered from left to right across
2458both of the vectors. The shuffle mask operand specifies, for each element of
2459the result vector, which element of the two input registers the result element
2460gets. The element selector may be undef (meaning "don't care") and the second
2461operand may be undef if performing a shuffle from only one vector.
2462</p>
2463
2464<h5>Example:</h5>
2465
2466<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2467 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2468 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2469 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2470 &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]2471</pre>
2472</div>
2473
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]2474
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2475<!-- ======================================================================= -->
2476<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2477 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2478</div>
2479
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2480<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2481
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2482<p>A key design point of an SSA-based representation is how it
2483represents memory. In LLVM, no memory locations are in SSA form, which
2484makes things very simple. This section describes how to read, write,
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2485allocate, and free memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2486
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2487</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2488
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2489<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2490<div class="doc_subsubsection">
2491 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2492</div>
2493
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2494<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2495
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2496<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2497
2498<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2499 &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]2500</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2501
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2502<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2503
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2504<p>The '<tt>malloc</tt>' instruction allocates memory from the system
2505heap and returns a pointer to it.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2506
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2507<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2508
2509<p>The '<tt>malloc</tt>' instruction allocates
2510<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswell6e4ca612004-02-24 16:13:56 +0000[diff] [blame]2511bytes of memory from the operating system and returns a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2512appropriate type to the program. If "NumElements" is specified, it is the
2513number of elements allocated. If an alignment is specified, the value result
2514of the allocation is guaranteed to be aligned to at least that boundary. If
2515not specified, or if zero, the target can choose to align the allocation on any
2516convenient boundary.</p>
2517
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2518<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2519
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2520<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2521
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2522<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
2523a pointer is returned.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2524
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2525<h5>Example:</h5>
2526
2527<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2528 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2529
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2530 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
2531 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
2532 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
2533 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
2534 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2535</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2536</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2537
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2538<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2539<div class="doc_subsubsection">
2540 <a name="i_free">'<tt>free</tt>' Instruction</a>
2541</div>
2542
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2543<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2544
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2545<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2546
2547<pre>
2548 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2549</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2550
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2551<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2552
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2553<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2554memory heap to be reallocated in the future.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2555
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2556<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2557
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2558<p>'<tt>value</tt>' shall be a pointer value that points to a value
2559that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
2560instruction.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2561
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2562<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2563
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2564<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2565after this instruction executes.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2566
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2567<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2568
2569<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2570 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
2571 free [4 x i8]* %array
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2572</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2573</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2574
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2575<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2576<div class="doc_subsubsection">
2577 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
2578</div>
2579
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2580<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2581
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2582<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2583
2584<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2585 &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]2586</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2587
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2588<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2589
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2590<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
2591currently executing function, to be automatically released when this function
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2592returns to its caller.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2593
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2594<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2595
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2596<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2597bytes of memory on the runtime stack, returning a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2598appropriate type to the program. If "NumElements" is specified, it is the
2599number of elements allocated. If an alignment is specified, the value result
2600of the allocation is guaranteed to be aligned to at least that boundary. If
2601not specified, or if zero, the target can choose to align the allocation on any
2602convenient boundary.</p>
2603
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2604<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2605
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2606<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2607
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2608<p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2609memory is automatically released when the function returns. The '<tt>alloca</tt>'
2610instruction is commonly used to represent automatic variables that must
2611have an address available. When the function returns (either with the <tt><a
John Criswelldae2e932005-05-12 16:55:34 +0000[diff] [blame]2612 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]2613instructions), the memory is reclaimed.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2614
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2615<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2616
2617<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2618 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
2619 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
2620 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
2621 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2622</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2623</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2624
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2625<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2626<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
2627Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2628<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2629<h5>Syntax:</h5>
Christopher Lamb2330e4d2007-04-21 08:16:25 +0000[diff] [blame]2630<pre> &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]<br> &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]<br></pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2631<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2632<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2633<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2634<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2635address from which to load. The pointer must point to a <a
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]2636 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2637marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2638the number or order of execution of this <tt>load</tt> with other
2639volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
2640instructions. </p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2641<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2642<p>The location of memory pointed to is loaded.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2643<h5>Examples:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2644<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2645 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2646 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2647 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2648</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2649</div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2650<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2651<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
2652Instruction</a> </div>
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]2653<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2654<h5>Syntax:</h5>
Christopher Lamb2330e4d2007-04-21 08:16:25 +0000[diff] [blame]2655<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
2656 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2657</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2658<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2659<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2660<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2661<p>There are two arguments to the '<tt>store</tt>' instruction: a value
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2662to store and an address at which to store it. The type of the '<tt>&lt;pointer&gt;</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2663operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2664operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2665optimizer is not allowed to modify the number or order of execution of
2666this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
2667 href="#i_store">store</a></tt> instructions.</p>
2668<h5>Semantics:</h5>
2669<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
2670at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2671<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2672<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2673 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2674 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2675 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2676</pre>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2677</div>
2678
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2679<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2680<div class="doc_subsubsection">
2681 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
2682</div>
2683
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2684<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2685<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2686<pre>
2687 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
2688</pre>
2689
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2690<h5>Overview:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2691
2692<p>
2693The '<tt>getelementptr</tt>' instruction is used to get the address of a
2694subelement of an aggregate data structure.</p>
2695
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2696<h5>Arguments:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2697
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2698<p>This instruction takes a list of integer operands that indicate what
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2699elements of the aggregate object to index to. The actual types of the arguments
2700provided depend on the type of the first pointer argument. The
2701'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2702levels 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]2703structure, only <tt>i32</tt> integer constants are allowed. When indexing
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2704into an array or pointer, only integers of 32 or 64 bits are allowed, and will
2705be sign extended to 64-bit values.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2706
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2707<p>For example, let's consider a C code fragment and how it gets
2708compiled to LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2709
2710<pre>
2711 struct RT {
2712 char A;
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2713 i32 B[10][20];
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2714 char C;
2715 };
2716 struct ST {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2717 i32 X;
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2718 double Y;
2719 struct RT Z;
2720 };
2721
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2722 define i32 *foo(struct ST *s) {
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2723 return &amp;s[1].Z.B[5][13];
2724 }
2725</pre>
2726
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2727<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2728
2729<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2730 %RT = type { i8 , [10 x [20 x i32]], i8 }
2731 %ST = type { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2732
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2733 define i32* %foo(%ST* %s) {
Brian Gaeke7283e7c2004-07-02 21:08:14 +0000[diff] [blame]2734 entry:
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2735 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
2736 ret i32* %reg
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2737 }
2738</pre>
2739
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2740<h5>Semantics:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2741
2742<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2743on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2744and <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]2745<a href="#t_integer">integer</a> type but the value will always be sign extended
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2746to 64-bits. <a href="#t_struct">Structure</a> types require <tt>i32</tt>
Reid Spencer42ddd842006-12-03 16:53:48 +0000[diff] [blame]2747<b>constants</b>.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2748
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2749<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]2750type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2751}</tt>' type, a structure. The second index indexes into the third element of
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2752the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
2753i8 }</tt>' type, another structure. The third index indexes into the second
2754element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2755array. The two dimensions of the array are subscripted into, yielding an
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2756'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
2757to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2758
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2759<p>Note that it is perfectly legal to index partially through a
2760structure, returning a pointer to an inner element. Because of this,
2761the LLVM code for the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2762
2763<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2764 define i32* %foo(%ST* %s) {
2765 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2766 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
2767 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2768 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
2769 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
2770 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2771 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2772</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2773
2774<p>Note that it is undefined to access an array out of bounds: array and
2775pointer indexes must always be within the defined bounds of the array type.
2776The one exception for this rules is zero length arrays. These arrays are
2777defined to be accessible as variable length arrays, which requires access
2778beyond the zero'th element.</p>
2779
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2780<p>The getelementptr instruction is often confusing. For some more insight
2781into how it works, see <a href="GetElementPtr.html">the getelementptr
2782FAQ</a>.</p>
2783
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2784<h5>Example:</h5>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2785
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2786<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2787 <i>; yields [12 x i8]*:aptr</i>
2788 %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2789</pre>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2790</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2791
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2792<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]2793<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2794</div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2795<div class="doc_text">
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]2796<p>The instructions in this category are the conversion instructions (casting)
2797which all take a single operand and a type. They perform various bit conversions
2798on the operand.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2799</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2800
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2801<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2802<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2803 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
2804</div>
2805<div class="doc_text">
2806
2807<h5>Syntax:</h5>
2808<pre>
2809 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2810</pre>
2811
2812<h5>Overview:</h5>
2813<p>
2814The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
2815</p>
2816
2817<h5>Arguments:</h5>
2818<p>
2819The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
2820be 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]2821and type of the result, which must be an <a href="#t_integer">integer</a>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2822type. The bit size of <tt>value</tt> must be larger than the bit size of
2823<tt>ty2</tt>. Equal sized types are not allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2824
2825<h5>Semantics:</h5>
2826<p>
2827The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2828and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
2829larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
2830It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2831
2832<h5>Example:</h5>
2833<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2834 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2835 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
2836 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2837</pre>
2838</div>
2839
2840<!-- _______________________________________________________________________ -->
2841<div class="doc_subsubsection">
2842 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
2843</div>
2844<div class="doc_text">
2845
2846<h5>Syntax:</h5>
2847<pre>
2848 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2849</pre>
2850
2851<h5>Overview:</h5>
2852<p>The '<tt>zext</tt>' instruction zero extends its operand to type
2853<tt>ty2</tt>.</p>
2854
2855
2856<h5>Arguments:</h5>
2857<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]2858<a href="#t_integer">integer</a> type, and a type to cast it to, which must
2859also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2860<tt>value</tt> must be smaller than the bit size of the destination type,
2861<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2862
2863<h5>Semantics:</h5>
2864<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
2865bits until it reaches the size of the destination type, <tt>ty2</tt>. When the
2866the operand and the type are the same size, no bit filling is done and the
2867cast is considered a <i>no-op cast</i> because no bits change (only the type
2868changes).</p>
2869
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]2870<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]2871
2872<h5>Example:</h5>
2873<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2874 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2875 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2876</pre>
2877</div>
2878
2879<!-- _______________________________________________________________________ -->
2880<div class="doc_subsubsection">
2881 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
2882</div>
2883<div class="doc_text">
2884
2885<h5>Syntax:</h5>
2886<pre>
2887 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2888</pre>
2889
2890<h5>Overview:</h5>
2891<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
2892
2893<h5>Arguments:</h5>
2894<p>
2895The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2896<a href="#t_integer">integer</a> type, and a type to cast it to, which must
2897also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2898<tt>value</tt> must be smaller than the bit size of the destination type,
2899<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2900
2901<h5>Semantics:</h5>
2902<p>
2903The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
2904bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
2905the type <tt>ty2</tt>. When the the operand and the type are the same size,
2906no bit filling is done and the cast is considered a <i>no-op cast</i> because
2907no bits change (only the type changes).</p>
2908
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2909<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]2910
2911<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2912<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2913 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2914 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2915</pre>
2916</div>
2917
2918<!-- _______________________________________________________________________ -->
2919<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]2920 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
2921</div>
2922
2923<div class="doc_text">
2924
2925<h5>Syntax:</h5>
2926
2927<pre>
2928 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2929</pre>
2930
2931<h5>Overview:</h5>
2932<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
2933<tt>ty2</tt>.</p>
2934
2935
2936<h5>Arguments:</h5>
2937<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
2938 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
2939cast it to. The size of <tt>value</tt> must be larger than the size of
2940<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
2941<i>no-op cast</i>.</p>
2942
2943<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2944<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
2945<a href="#t_floating">floating point</a> type to a smaller
2946<a href="#t_floating">floating point</a> type. If the value cannot fit within
2947the destination type, <tt>ty2</tt>, then the results are undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]2948
2949<h5>Example:</h5>
2950<pre>
2951 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
2952 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
2953</pre>
2954</div>
2955
2956<!-- _______________________________________________________________________ -->
2957<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2958 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
2959</div>
2960<div class="doc_text">
2961
2962<h5>Syntax:</h5>
2963<pre>
2964 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2965</pre>
2966
2967<h5>Overview:</h5>
2968<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
2969floating point value.</p>
2970
2971<h5>Arguments:</h5>
2972<p>The '<tt>fpext</tt>' instruction takes a
2973<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2974and a <a href="#t_floating">floating point</a> type to cast it to. The source
2975type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2976
2977<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2978<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]2979<a href="#t_floating">floating point</a> type to a larger
2980<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2981used to make a <i>no-op cast</i> because it always changes bits. Use
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2982<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]2983
2984<h5>Example:</h5>
2985<pre>
2986 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
2987 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
2988</pre>
2989</div>
2990
2991<!-- _______________________________________________________________________ -->
2992<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]2993 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2994</div>
2995<div class="doc_text">
2996
2997<h5>Syntax:</h5>
2998<pre>
2999 &lt;result&gt; = fp2uint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3000</pre>
3001
3002<h5>Overview:</h5>
3003<p>The '<tt>fp2uint</tt>' converts a floating point <tt>value</tt> to its
3004unsigned integer equivalent of type <tt>ty2</tt>.
3005</p>
3006
3007<h5>Arguments:</h5>
3008<p>The '<tt>fp2uint</tt>' instruction takes a value to cast, which must be a
3009<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]3010must be an <a href="#t_integer">integer</a> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3011
3012<h5>Semantics:</h5>
3013<p> The '<tt>fp2uint</tt>' instruction converts its
3014<a href="#t_floating">floating point</a> operand into the nearest (rounding
3015towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3016the results are undefined.</p>
3017
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3018<p>When converting to i1, the conversion is done as a comparison against
3019zero. If the <tt>value</tt> was zero, the i1 result will be <tt>false</tt>.
3020If 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]3021
3022<h5>Example:</h5>
3023<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3024 %X = fp2uint double 123.0 to i32 <i>; yields i32:123</i>
3025 %Y = fp2uint float 1.0E+300 to i1 <i>; yields i1:true</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3026 %X = fp2uint float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3027</pre>
3028</div>
3029
3030<!-- _______________________________________________________________________ -->
3031<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3032 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3033</div>
3034<div class="doc_text">
3035
3036<h5>Syntax:</h5>
3037<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3038 &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]3039</pre>
3040
3041<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3042<p>The '<tt>fptosi</tt>' instruction converts
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3043<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]3044</p>
3045
3046
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3047<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3048<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]3049<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]3050must also be an <a href="#t_integer">integer</a> type.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3051
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3052<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3053<p>The '<tt>fptosi</tt>' instruction converts its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3054<a href="#t_floating">floating point</a> operand into the nearest (rounding
3055towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3056the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3057
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3058<p>When converting to i1, the conversion is done as a comparison against
3059zero. If the <tt>value</tt> was zero, the i1 result will be <tt>false</tt>.
3060If 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]3061
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3062<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3063<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3064 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
3065 %Y = fptosi float 1.0E-247 to i1 <i>; yields i1:true</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3066 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3067</pre>
3068</div>
3069
3070<!-- _______________________________________________________________________ -->
3071<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3072 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3073</div>
3074<div class="doc_text">
3075
3076<h5>Syntax:</h5>
3077<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3078 &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]3079</pre>
3080
3081<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3082<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3083integer and converts that value to the <tt>ty2</tt> type.</p>
3084
3085
3086<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3087<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]3088<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]3089be a <a href="#t_floating">floating point</a> type.</p>
3090
3091<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3092<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3093integer quantity and converts it to the corresponding floating point value. If
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]3094the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3095
3096
3097<h5>Example:</h5>
3098<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3099 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame^]3100 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3101</pre>
3102</div>
3103
3104<!-- _______________________________________________________________________ -->
3105<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3106 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3107</div>
3108<div class="doc_text">
3109
3110<h5>Syntax:</h5>
3111<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3112 &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]3113</pre>
3114
3115<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3116<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3117integer and converts that value to the <tt>ty2</tt> type.</p>
3118
3119<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3120<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]3121<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]3122a <a href="#t_floating">floating point</a> type.</p>
3123
3124<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3125<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3126integer quantity and converts it to the corresponding floating point value. If
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]3127the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3128
3129<h5>Example:</h5>
3130<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3131 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame^]3132 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3133</pre>
3134</div>
3135
3136<!-- _______________________________________________________________________ -->
3137<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3138 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3139</div>
3140<div class="doc_text">
3141
3142<h5>Syntax:</h5>
3143<pre>
3144 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3145</pre>
3146
3147<h5>Overview:</h5>
3148<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3149the integer type <tt>ty2</tt>.</p>
3150
3151<h5>Arguments:</h5>
3152<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3153must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3154<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
3155
3156<h5>Semantics:</h5>
3157<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3158<tt>ty2</tt> by interpreting the pointer value as an integer and either
3159truncating or zero extending that value to the size of the integer type. If
3160<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3161<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame^]3162are the same size, then nothing is done (<i>no-op cast</i>) other than a type
3163change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3164
3165<h5>Example:</h5>
3166<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame^]3167 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
3168 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3169</pre>
3170</div>
3171
3172<!-- _______________________________________________________________________ -->
3173<div class="doc_subsubsection">
3174 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3175</div>
3176<div class="doc_text">
3177
3178<h5>Syntax:</h5>
3179<pre>
3180 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3181</pre>
3182
3183<h5>Overview:</h5>
3184<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3185a pointer type, <tt>ty2</tt>.</p>
3186
3187<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3188<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3189value to cast, and a type to cast it to, which must be a
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]3190<a href="#t_pointer">pointer</a> type.
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3191
3192<h5>Semantics:</h5>
3193<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3194<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3195the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3196size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3197the size of a pointer then a zero extension is done. If they are the same size,
3198nothing is done (<i>no-op cast</i>).</p>
3199
3200<h5>Example:</h5>
3201<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame^]3202 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
3203 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
3204 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3205</pre>
3206</div>
3207
3208<!-- _______________________________________________________________________ -->
3209<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3210 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3211</div>
3212<div class="doc_text">
3213
3214<h5>Syntax:</h5>
3215<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3216 &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]3217</pre>
3218
3219<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3220<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3221<tt>ty2</tt> without changing any bits.</p>
3222
3223<h5>Arguments:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3224<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3225a first class value, and a type to cast it to, which must also be a <a
3226 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
Reid Spencer19b569f2007-01-09 20:08:58 +0000[diff] [blame]3227and the destination type, <tt>ty2</tt>, must be identical. If the source
3228type is a pointer, the destination type must also be a pointer.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3229
3230<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3231<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3232<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3233this conversion. The conversion is done as if the <tt>value</tt> had been
3234stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3235converted to other pointer types with this instruction. To convert pointers to
3236other types, use the <a href="#i_inttoptr">inttoptr</a> or
3237<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3238
3239<h5>Example:</h5>
3240<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame^]3241 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3242 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
3243 %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3244</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3245</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3246
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3247<!-- ======================================================================= -->
3248<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3249<div class="doc_text">
3250<p>The instructions in this category are the "miscellaneous"
3251instructions, which defy better classification.</p>
3252</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3253
3254<!-- _______________________________________________________________________ -->
3255<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3256</div>
3257<div class="doc_text">
3258<h5>Syntax:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame^]3259<pre> &lt;result&gt; = icmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {i1}:result</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3260</pre>
3261<h5>Overview:</h5>
3262<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
3263of its two integer operands.</p>
3264<h5>Arguments:</h5>
3265<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame^]3266the condition code indicating the kind of comparison to perform. It is not
3267a value, just a keyword. The possible condition code are:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3268<ol>
3269 <li><tt>eq</tt>: equal</li>
3270 <li><tt>ne</tt>: not equal </li>
3271 <li><tt>ugt</tt>: unsigned greater than</li>
3272 <li><tt>uge</tt>: unsigned greater or equal</li>
3273 <li><tt>ult</tt>: unsigned less than</li>
3274 <li><tt>ule</tt>: unsigned less or equal</li>
3275 <li><tt>sgt</tt>: signed greater than</li>
3276 <li><tt>sge</tt>: signed greater or equal</li>
3277 <li><tt>slt</tt>: signed less than</li>
3278 <li><tt>sle</tt>: signed less or equal</li>
3279</ol>
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3280<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3281<a href="#t_pointer">pointer</a> typed. They must also be identical types.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3282<h5>Semantics:</h5>
3283<p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3284the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3285yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3286<ol>
3287 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3288 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3289 </li>
3290 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3291 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3292 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3293 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3294 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3295 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3296 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3297 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3298 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3299 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3300 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3301 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3302 <li><tt>sge</tt>: interprets the operands as signed values and yields
3303 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3304 <li><tt>slt</tt>: interprets the operands as signed values and yields
3305 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3306 <li><tt>sle</tt>: interprets the operands as signed values and yields
3307 <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]3308</ol>
3309<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame^]3310values are compared as if they were integers.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3311
3312<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3313<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3314 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3315 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3316 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3317 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3318 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3319</pre>
3320</div>
3321
3322<!-- _______________________________________________________________________ -->
3323<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3324</div>
3325<div class="doc_text">
3326<h5>Syntax:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame^]3327<pre> &lt;result&gt; = fcmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {i1}:result</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3328</pre>
3329<h5>Overview:</h5>
3330<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3331of its floating point operands.</p>
3332<h5>Arguments:</h5>
3333<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame^]3334the condition code indicating the kind of comparison to perform. It is not
3335a value, just a keyword. The possible condition code are:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3336<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3337 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3338 <li><tt>oeq</tt>: ordered and equal</li>
3339 <li><tt>ogt</tt>: ordered and greater than </li>
3340 <li><tt>oge</tt>: ordered and greater than or equal</li>
3341 <li><tt>olt</tt>: ordered and less than </li>
3342 <li><tt>ole</tt>: ordered and less than or equal</li>
3343 <li><tt>one</tt>: ordered and not equal</li>
3344 <li><tt>ord</tt>: ordered (no nans)</li>
3345 <li><tt>ueq</tt>: unordered or equal</li>
3346 <li><tt>ugt</tt>: unordered or greater than </li>
3347 <li><tt>uge</tt>: unordered or greater than or equal</li>
3348 <li><tt>ult</tt>: unordered or less than </li>
3349 <li><tt>ule</tt>: unordered or less than or equal</li>
3350 <li><tt>une</tt>: unordered or not equal</li>
3351 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3352 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3353</ol>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame^]3354<p><i>Ordered</i> means that neither operand is a QNAN while
Reid Spencer93a49852006-12-06 07:08:07 +0000[diff] [blame]3355<i>unordered</i> means that either operand may be a QNAN.</p>
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3356<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be
3357<a href="#t_floating">floating point</a> typed. They must have identical
3358types.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3359<h5>Semantics:</h5>
3360<p>The '<tt>fcmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3361the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3362yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3363<ol>
3364 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3365 <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]3366 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3367 <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]3368 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3369 <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]3370 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3371 <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]3372 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3373 <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]3374 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3375 <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]3376 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3377 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3378 <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]3379 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3380 <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]3381 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3382 <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]3383 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3384 <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]3385 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3386 <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]3387 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3388 <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]3389 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3390 <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]3391 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3392</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3393
3394<h5>Example:</h5>
3395<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3396 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3397 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3398 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3399</pre>
3400</div>
3401
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3402<!-- _______________________________________________________________________ -->
3403<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
3404Instruction</a> </div>
3405<div class="doc_text">
3406<h5>Syntax:</h5>
3407<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
3408<h5>Overview:</h5>
3409<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
3410the SSA graph representing the function.</p>
3411<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame^]3412<p>The type of the incoming values is specified with the first type
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3413field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
3414as arguments, with one pair for each predecessor basic block of the
3415current block. Only values of <a href="#t_firstclass">first class</a>
3416type may be used as the value arguments to the PHI node. Only labels
3417may be used as the label arguments.</p>
3418<p>There must be no non-phi instructions between the start of a basic
3419block and the PHI instructions: i.e. PHI instructions must be first in
3420a basic block.</p>
3421<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame^]3422<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
3423specified by the pair corresponding to the predecessor basic block that executed
3424just prior to the current block.</p>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3425<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3426<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]3427</div>
3428
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3429<!-- _______________________________________________________________________ -->
3430<div class="doc_subsubsection">
3431 <a name="i_select">'<tt>select</tt>' Instruction</a>
3432</div>
3433
3434<div class="doc_text">
3435
3436<h5>Syntax:</h5>
3437
3438<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3439 &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]3440</pre>
3441
3442<h5>Overview:</h5>
3443
3444<p>
3445The '<tt>select</tt>' instruction is used to choose one value based on a
3446condition, without branching.
3447</p>
3448
3449
3450<h5>Arguments:</h5>
3451
3452<p>
3453The '<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.
3454</p>
3455
3456<h5>Semantics:</h5>
3457
3458<p>
3459If the boolean condition evaluates to true, the instruction returns the first
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3460value argument; otherwise, it returns the second value argument.
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3461</p>
3462
3463<h5>Example:</h5>
3464
3465<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3466 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3467</pre>
3468</div>
3469
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]3470
3471<!-- _______________________________________________________________________ -->
3472<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3473 <a name="i_call">'<tt>call</tt>' Instruction</a>
3474</div>
3475
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3476<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3477
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3478<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3479<pre>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3480 &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]3481</pre>
3482
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3483<h5>Overview:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3484
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3485<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3486
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3487<h5>Arguments:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3488
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3489<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3490
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3491<ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3492 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3493 <p>The optional "tail" marker indicates whether the callee function accesses
3494 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3495 function call is eligible for tail call optimization. Note that calls may
3496 be marked "tail" even if they do not occur before a <a
3497 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3498 </li>
3499 <li>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3500 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3501 convention</a> the call should use. If none is specified, the call defaults
3502 to using C calling conventions.
3503 </li>
3504 <li>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3505 <p>'<tt>ty</tt>': shall be the signature of the pointer to function value
3506 being invoked. The argument types must match the types implied by this
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3507 signature. This type can be omitted if the function is not varargs and
3508 if the function type does not return a pointer to a function.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3509 </li>
3510 <li>
3511 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
3512 be invoked. In most cases, this is a direct function invocation, but
3513 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3514 to function value.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3515 </li>
3516 <li>
3517 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencera7e302a2005-05-01 22:22:57 +0000[diff] [blame]3518 function signature argument types. All arguments must be of
3519 <a href="#t_firstclass">first class</a> type. If the function signature
3520 indicates the function accepts a variable number of arguments, the extra
3521 arguments can be specified.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3522 </li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3523</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3524
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3525<h5>Semantics:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3526
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3527<p>The '<tt>call</tt>' instruction is used to cause control flow to
3528transfer to a specified function, with its incoming arguments bound to
3529the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
3530instruction in the called function, control flow continues with the
3531instruction after the function call, and the return value of the
3532function is bound to the result argument. This is a simpler case of
3533the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3534
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3535<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3536
3537<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3538 %retval = call i32 %test(i32 %argc)
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame^]3539 call i32(i8 *, ...) *%printf(i8 * %msg, i32 12, i8 42);
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3540 %X = tail call i32 %foo()
3541 %Y = tail call <a href="#callingconv">fastcc</a> i32 %foo()
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3542</pre>
3543
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3544</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3545
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3546<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3547<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3548 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3549</div>
3550
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3551<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3552
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3553<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3554
3555<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3556 &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]3557</pre>
3558
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3559<h5>Overview:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3560
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3561<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3562the "variable argument" area of a function call. It is used to implement the
3563<tt>va_arg</tt> macro in C.</p>
3564
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3565<h5>Arguments:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3566
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3567<p>This instruction takes a <tt>va_list*</tt> value and the type of
3568the argument. It returns a value of the specified argument type and
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame^]3569increments the <tt>va_list</tt> to point to the next argument. The
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3570actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3571
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3572<h5>Semantics:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3573
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3574<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
3575type from the specified <tt>va_list</tt> and causes the
3576<tt>va_list</tt> to point to the next argument. For more information,
3577see the variable argument handling <a href="#int_varargs">Intrinsic
3578Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3579
3580<p>It is legal for this instruction to be called in a function which does not
3581take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3582function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3583
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3584<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3585href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3586argument.</p>
3587
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3588<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3589
3590<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
3591
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3592</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3593
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3594<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3595<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
3596<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3597
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3598<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3599
3600<p>LLVM supports the notion of an "intrinsic function". These functions have
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]3601well known names and semantics and are required to follow certain restrictions.
3602Overall, these intrinsics represent an extension mechanism for the LLVM
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame^]3603language that does not require changing all of the transformations in LLVM when
3604adding to the language (or the bytecode reader/writer, the parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3605
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3606<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame^]3607prefix is reserved in LLVM for intrinsic names; thus, function names may not
3608begin with this prefix. Intrinsic functions must always be external functions:
3609you cannot define the body of intrinsic functions. Intrinsic functions may
3610only be used in call or invoke instructions: it is illegal to take the address
3611of an intrinsic function. Additionally, because intrinsic functions are part
3612of the LLVM language, it is required if any are added that they be documented
3613here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3614
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame^]3615<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]3616a family of functions that perform the same operation but on different data
3617types. This is most frequent with the integer types. Since LLVM can represent
3618over 8 million different integer types, there is a way to declare an intrinsic
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame^]3619that can be overloaded based on its arguments. Such an intrinsic will have the
3620names of its argument types encoded into its function name, each
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]3621preceded by a period. For example, the <tt>llvm.ctpop</tt> function can take an
3622integer of any width. This leads to a family of functions such as
3623<tt>i32 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i32 @llvm.ctpop.i29(i29 %val)</tt>.
3624</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3625
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]3626
3627<p>To learn how to add an intrinsic function, please see the
3628<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3629</p>
3630
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3631</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3632
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3633<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3634<div class="doc_subsection">
3635 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
3636</div>
3637
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3638<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3639
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3640<p>Variable argument support is defined in LLVM with the <a
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3641 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3642intrinsic functions. These functions are related to the similarly
3643named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3644
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3645<p>All of these functions operate on arguments that use a
3646target-specific value type "<tt>va_list</tt>". The LLVM assembly
3647language reference manual does not define what this type is, so all
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame^]3648transformations should be prepared to handle these functions regardless of
3649the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3650
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]3651<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]3652instruction and the variable argument handling intrinsic functions are
3653used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3654
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3655<pre>
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3656define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3657 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame^]3658 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3659 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3660 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3661
3662 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame^]3663 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3664
3665 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame^]3666 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3667 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame^]3668 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3669 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3670
3671 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3672 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3673 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3674}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3675
3676declare void @llvm.va_start(i8*)
3677declare void @llvm.va_copy(i8*, i8*)
3678declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3679</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3680</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3681
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3682<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3683<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3684 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3685</div>
3686
3687
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3688<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3689<h5>Syntax:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3690<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3691<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3692<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
3693<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
3694href="#i_va_arg">va_arg</a></tt>.</p>
3695
3696<h5>Arguments:</h5>
3697
3698<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
3699
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3700<h5>Semantics:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3701
3702<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
3703macro available in C. In a target-dependent way, it initializes the
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame^]3704<tt>va_list</tt> element to which the argument points, so that the next call to
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3705<tt>va_arg</tt> will produce the first variable argument passed to the function.
3706Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame^]3707last argument of the function as the compiler can figure that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3708
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3709</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3710
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3711<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3712<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3713 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3714</div>
3715
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3716<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3717<h5>Syntax:</h5>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3718<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3719<h5>Overview:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3720
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame^]3721<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3722which has been initialized previously with <tt><a href="#int_va_start">llvm.va_start</a></tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3723or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3724
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3725<h5>Arguments:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3726
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame^]3727<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3728
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3729<h5>Semantics:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3730
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3731<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame^]3732macro available in C. In a target-dependent way, it destroys the
3733<tt>va_list</tt> element to which the argument points. Calls to <a
3734href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
3735<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
3736<tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3737
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3738</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3739
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3740<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3741<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3742 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3743</div>
3744
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3745<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3746
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3747<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3748
3749<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3750 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3751</pre>
3752
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3753<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3754
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame^]3755<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
3756from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3757
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3758<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3759
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3760<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]3761The 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]3762
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3763
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3764<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3765
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame^]3766<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
3767macro available in C. In a target-dependent way, it copies the source
3768<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
3769intrinsic is necessary because the <tt><a href="#int_va_start">
3770llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
3771example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3772
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3773</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3774
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3775<!-- ======================================================================= -->
3776<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3777 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
3778</div>
3779
3780<div class="doc_text">
3781
3782<p>
3783LLVM support for <a href="GarbageCollection.html">Accurate Garbage
3784Collection</a> requires the implementation and generation of these intrinsics.
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3785These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3786stack</a>, as well as garbage collector implementations that require <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3787href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3788Front-ends for type-safe garbage collected languages should generate these
3789intrinsics to make use of the LLVM garbage collectors. For more details, see <a
3790href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
3791</p>
3792</div>
3793
3794<!-- _______________________________________________________________________ -->
3795<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3796 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3797</div>
3798
3799<div class="doc_text">
3800
3801<h5>Syntax:</h5>
3802
3803<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3804 declare void @llvm.gcroot(&lt;ty&gt;** %ptrloc, &lt;ty2&gt;* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3805</pre>
3806
3807<h5>Overview:</h5>
3808
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]3809<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]3810the code generator, and allows some metadata to be associated with it.</p>
3811
3812<h5>Arguments:</h5>
3813
3814<p>The first argument specifies the address of a stack object that contains the
3815root pointer. The second pointer (which must be either a constant or a global
3816value address) contains the meta-data to be associated with the root.</p>
3817
3818<h5>Semantics:</h5>
3819
3820<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
3821location. At compile-time, the code generator generates information to allow
3822the runtime to find the pointer at GC safe points.
3823</p>
3824
3825</div>
3826
3827
3828<!-- _______________________________________________________________________ -->
3829<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3830 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3831</div>
3832
3833<div class="doc_text">
3834
3835<h5>Syntax:</h5>
3836
3837<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3838 declare i8 * @llvm.gcread(i8 * %ObjPtr, i8 ** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3839</pre>
3840
3841<h5>Overview:</h5>
3842
3843<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
3844locations, allowing garbage collector implementations that require read
3845barriers.</p>
3846
3847<h5>Arguments:</h5>
3848
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3849<p>The second argument is the address to read from, which should be an address
3850allocated from the garbage collector. The first object is a pointer to the
3851start of the referenced object, if needed by the language runtime (otherwise
3852null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3853
3854<h5>Semantics:</h5>
3855
3856<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
3857instruction, but may be replaced with substantially more complex code by the
3858garbage collector runtime, as needed.</p>
3859
3860</div>
3861
3862
3863<!-- _______________________________________________________________________ -->
3864<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3865 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3866</div>
3867
3868<div class="doc_text">
3869
3870<h5>Syntax:</h5>
3871
3872<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3873 declare void @llvm.gcwrite(i8 * %P1, i8 * %Obj, i8 ** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3874</pre>
3875
3876<h5>Overview:</h5>
3877
3878<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
3879locations, allowing garbage collector implementations that require write
3880barriers (such as generational or reference counting collectors).</p>
3881
3882<h5>Arguments:</h5>
3883
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3884<p>The first argument is the reference to store, the second is the start of the
3885object to store it to, and the third is the address of the field of Obj to
3886store to. If the runtime does not require a pointer to the object, Obj may be
3887null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3888
3889<h5>Semantics:</h5>
3890
3891<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
3892instruction, but may be replaced with substantially more complex code by the
3893garbage collector runtime, as needed.</p>
3894
3895</div>
3896
3897
3898
3899<!-- ======================================================================= -->
3900<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3901 <a name="int_codegen">Code Generator Intrinsics</a>
3902</div>
3903
3904<div class="doc_text">
3905<p>
3906These intrinsics are provided by LLVM to expose special features that may only
3907be implemented with code generator support.
3908</p>
3909
3910</div>
3911
3912<!-- _______________________________________________________________________ -->
3913<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3914 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3915</div>
3916
3917<div class="doc_text">
3918
3919<h5>Syntax:</h5>
3920<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3921 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3922</pre>
3923
3924<h5>Overview:</h5>
3925
3926<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]3927The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
3928target-specific value indicating the return address of the current function
3929or one of its callers.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3930</p>
3931
3932<h5>Arguments:</h5>
3933
3934<p>
3935The argument to this intrinsic indicates which function to return the address
3936for. Zero indicates the calling function, one indicates its caller, etc. The
3937argument is <b>required</b> to be a constant integer value.
3938</p>
3939
3940<h5>Semantics:</h5>
3941
3942<p>
3943The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
3944the return address of the specified call frame, or zero if it cannot be
3945identified. The value returned by this intrinsic is likely to be incorrect or 0
3946for arguments other than zero, so it should only be used for debugging purposes.
3947</p>
3948
3949<p>
3950Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]3951aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3952source-language caller.
3953</p>
3954</div>
3955
3956
3957<!-- _______________________________________________________________________ -->
3958<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3959 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3960</div>
3961
3962<div class="doc_text">
3963
3964<h5>Syntax:</h5>
3965<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3966 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3967</pre>
3968
3969<h5>Overview:</h5>
3970
3971<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]3972The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
3973target-specific frame pointer value for the specified stack frame.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3974</p>
3975
3976<h5>Arguments:</h5>
3977
3978<p>
3979The argument to this intrinsic indicates which function to return the frame
3980pointer for. Zero indicates the calling function, one indicates its caller,
3981etc. The argument is <b>required</b> to be a constant integer value.
3982</p>
3983
3984<h5>Semantics:</h5>
3985
3986<p>
3987The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
3988the frame address of the specified call frame, or zero if it cannot be
3989identified. The value returned by this intrinsic is likely to be incorrect or 0
3990for arguments other than zero, so it should only be used for debugging purposes.
3991</p>
3992
3993<p>
3994Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]3995aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3996source-language caller.
3997</p>
3998</div>
3999
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4000<!-- _______________________________________________________________________ -->
4001<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4002 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4003</div>
4004
4005<div class="doc_text">
4006
4007<h5>Syntax:</h5>
4008<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4009 declare i8 *@llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4010</pre>
4011
4012<h5>Overview:</h5>
4013
4014<p>
4015The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4016the function stack, for use with <a href="#int_stackrestore">
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4017<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
4018features like scoped automatic variable sized arrays in C99.
4019</p>
4020
4021<h5>Semantics:</h5>
4022
4023<p>
4024This intrinsic returns a opaque pointer value that can be passed to <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4025href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4026<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
4027<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
4028state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
4029practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
4030that were allocated after the <tt>llvm.stacksave</tt> was executed.
4031</p>
4032
4033</div>
4034
4035<!-- _______________________________________________________________________ -->
4036<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4037 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4038</div>
4039
4040<div class="doc_text">
4041
4042<h5>Syntax:</h5>
4043<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4044 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4045</pre>
4046
4047<h5>Overview:</h5>
4048
4049<p>
4050The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
4051the function stack to the state it was in when the corresponding <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4052href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4053useful for implementing language features like scoped automatic variable sized
4054arrays in C99.
4055</p>
4056
4057<h5>Semantics:</h5>
4058
4059<p>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4060See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4061</p>
4062
4063</div>
4064
4065
4066<!-- _______________________________________________________________________ -->
4067<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4068 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4069</div>
4070
4071<div class="doc_text">
4072
4073<h5>Syntax:</h5>
4074<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4075 declare void @llvm.prefetch(i8 * &lt;address&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4076 i32 &lt;rw&gt;, i32 &lt;locality&gt;)
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4077</pre>
4078
4079<h5>Overview:</h5>
4080
4081
4082<p>
4083The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4084a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
4085no
4086effect on the behavior of the program but can change its performance
Chris Lattner2a615362005-02-28 19:47:14 +0000[diff] [blame]4087characteristics.
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4088</p>
4089
4090<h5>Arguments:</h5>
4091
4092<p>
4093<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
4094determining if the fetch should be for a read (0) or write (1), and
4095<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattneraeffb4a2005-03-07 20:31:38 +0000[diff] [blame]4096locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4097<tt>locality</tt> arguments must be constant integers.
4098</p>
4099
4100<h5>Semantics:</h5>
4101
4102<p>
4103This intrinsic does not modify the behavior of the program. In particular,
4104prefetches cannot trap and do not produce a value. On targets that support this
4105intrinsic, the prefetch can provide hints to the processor cache for better
4106performance.
4107</p>
4108
4109</div>
4110
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4111<!-- _______________________________________________________________________ -->
4112<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4113 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4114</div>
4115
4116<div class="doc_text">
4117
4118<h5>Syntax:</h5>
4119<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4120 declare void @llvm.pcmarker( i32 &lt;id&gt; )
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4121</pre>
4122
4123<h5>Overview:</h5>
4124
4125
4126<p>
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4127The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
4128(PC) in a region of
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4129code to simulators and other tools. The method is target specific, but it is
4130expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]4131The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnerd07c3f42005-11-15 06:07:55 +0000[diff] [blame]4132after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb3e7afd2006-03-24 07:16:10 +0000[diff] [blame]4133optimizations. The intended use is to be inserted after optimizations to allow
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4134correlations of simulation runs.
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4135</p>
4136
4137<h5>Arguments:</h5>
4138
4139<p>
4140<tt>id</tt> is a numerical id identifying the marker.
4141</p>
4142
4143<h5>Semantics:</h5>
4144
4145<p>
4146This intrinsic does not modify the behavior of the program. Backends that do not
4147support this intrinisic may ignore it.
4148</p>
4149
4150</div>
4151
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4152<!-- _______________________________________________________________________ -->
4153<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4154 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4155</div>
4156
4157<div class="doc_text">
4158
4159<h5>Syntax:</h5>
4160<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4161 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4162</pre>
4163
4164<h5>Overview:</h5>
4165
4166
4167<p>
4168The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
4169counter register (or similar low latency, high accuracy clocks) on those targets
4170that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
4171As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
4172should only be used for small timings.
4173</p>
4174
4175<h5>Semantics:</h5>
4176
4177<p>
4178When directly supported, reading the cycle counter should not modify any memory.
4179Implementations are allowed to either return a application specific value or a
4180system wide value. On backends without support, this is lowered to a constant 0.
4181</p>
4182
4183</div>
4184
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4185<!-- ======================================================================= -->
4186<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4187 <a name="int_libc">Standard C Library Intrinsics</a>
4188</div>
4189
4190<div class="doc_text">
4191<p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4192LLVM provides intrinsics for a few important standard C library functions.
4193These intrinsics allow source-language front-ends to pass information about the
4194alignment of the pointer arguments to the code generator, providing opportunity
4195for more efficient code generation.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4196</p>
4197
4198</div>
4199
4200<!-- _______________________________________________________________________ -->
4201<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4202 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4203</div>
4204
4205<div class="doc_text">
4206
4207<h5>Syntax:</h5>
4208<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4209 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4210 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4211 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4212 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4213</pre>
4214
4215<h5>Overview:</h5>
4216
4217<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4218The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4219location to the destination location.
4220</p>
4221
4222<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4223Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4224intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4225</p>
4226
4227<h5>Arguments:</h5>
4228
4229<p>
4230The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4231the source. The third argument is an integer argument
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4232specifying the number of bytes to copy, and the fourth argument is the alignment
4233of the source and destination locations.
4234</p>
4235
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4236<p>
4237If 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]4238the caller guarantees that both the source and destination pointers are aligned
4239to that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4240</p>
4241
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4242<h5>Semantics:</h5>
4243
4244<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4245The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4246location to the destination location, which are not allowed to overlap. It
4247copies "len" bytes of memory over. If the argument is known to be aligned to
4248some boundary, this can be specified as the fourth argument, otherwise it should
4249be set to 0 or 1.
4250</p>
4251</div>
4252
4253
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4254<!-- _______________________________________________________________________ -->
4255<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4256 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4257</div>
4258
4259<div class="doc_text">
4260
4261<h5>Syntax:</h5>
4262<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4263 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4264 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4265 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4266 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4267</pre>
4268
4269<h5>Overview:</h5>
4270
4271<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4272The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
4273location to the destination location. It is similar to the
4274'<tt>llvm.memcmp</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4275</p>
4276
4277<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4278Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
4279intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4280</p>
4281
4282<h5>Arguments:</h5>
4283
4284<p>
4285The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4286the source. The third argument is an integer argument
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4287specifying the number of bytes to copy, and the fourth argument is the alignment
4288of the source and destination locations.
4289</p>
4290
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4291<p>
4292If 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]4293the caller guarantees that the source and destination pointers are aligned to
4294that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4295</p>
4296
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4297<h5>Semantics:</h5>
4298
4299<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4300The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4301location to the destination location, which may overlap. It
4302copies "len" bytes of memory over. If the argument is known to be aligned to
4303some boundary, this can be specified as the fourth argument, otherwise it should
4304be set to 0 or 1.
4305</p>
4306</div>
4307
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4308
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4309<!-- _______________________________________________________________________ -->
4310<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4311 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4312</div>
4313
4314<div class="doc_text">
4315
4316<h5>Syntax:</h5>
4317<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4318 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4319 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4320 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4321 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4322</pre>
4323
4324<h5>Overview:</h5>
4325
4326<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4327The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4328byte value.
4329</p>
4330
4331<p>
4332Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
4333does not return a value, and takes an extra alignment argument.
4334</p>
4335
4336<h5>Arguments:</h5>
4337
4338<p>
4339The first argument is a pointer to the destination to fill, the second is the
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4340byte value to fill it with, the third argument is an integer
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4341argument specifying the number of bytes to fill, and the fourth argument is the
4342known alignment of destination location.
4343</p>
4344
4345<p>
4346If 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]4347the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4348</p>
4349
4350<h5>Semantics:</h5>
4351
4352<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4353The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
4354the
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4355destination location. If the argument is known to be aligned to some boundary,
4356this can be specified as the fourth argument, otherwise it should be set to 0 or
43571.
4358</p>
4359</div>
4360
4361
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4362<!-- _______________________________________________________________________ -->
4363<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4364 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4365</div>
4366
4367<div class="doc_text">
4368
4369<h5>Syntax:</h5>
4370<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4371 declare float @llvm.sqrt.f32(float %Val)
4372 declare double @llvm.sqrt.f64(double %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4373</pre>
4374
4375<h5>Overview:</h5>
4376
4377<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4378The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4379returning the same value as the libm '<tt>sqrt</tt>' function would. Unlike
4380<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
4381negative numbers (which allows for better optimization).
4382</p>
4383
4384<h5>Arguments:</h5>
4385
4386<p>
4387The argument and return value are floating point numbers of the same type.
4388</p>
4389
4390<h5>Semantics:</h5>
4391
4392<p>
4393This function returns the sqrt of the specified operand if it is a positive
4394floating point number.
4395</p>
4396</div>
4397
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4398<!-- _______________________________________________________________________ -->
4399<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4400 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4401</div>
4402
4403<div class="doc_text">
4404
4405<h5>Syntax:</h5>
4406<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4407 declare float @llvm.powi.f32(float %Val, i32 %power)
4408 declare double @llvm.powi.f64(double %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4409</pre>
4410
4411<h5>Overview:</h5>
4412
4413<p>
4414The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
4415specified (positive or negative) power. The order of evaluation of
4416multiplications is not defined.
4417</p>
4418
4419<h5>Arguments:</h5>
4420
4421<p>
4422The second argument is an integer power, and the first is a value to raise to
4423that power.
4424</p>
4425
4426<h5>Semantics:</h5>
4427
4428<p>
4429This function returns the first value raised to the second power with an
4430unspecified sequence of rounding operations.</p>
4431</div>
4432
4433
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4434<!-- ======================================================================= -->
4435<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4436 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4437</div>
4438
4439<div class="doc_text">
4440<p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4441LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4442These allow efficient code generation for some algorithms.
4443</p>
4444
4445</div>
4446
4447<!-- _______________________________________________________________________ -->
4448<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4449 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4450</div>
4451
4452<div class="doc_text">
4453
4454<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4455<p>This is an overloaded intrinsic function. You can use bswap on any integer
4456type that is an even number of bytes (i.e. BitWidth % 16 == 0). Note the suffix
4457that includes the type for the result and the operand.
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4458<pre>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4459 declare i16 @llvm.bswap.i16.i16(i16 &lt;id&gt;)
4460 declare i32 @llvm.bswap.i32.i32(i32 &lt;id&gt;)
Reid Spencer543ab1d2007-04-02 00:19:52 +0000[diff] [blame]4461 declare i64 @llvm.bswap.i64.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4462</pre>
4463
4464<h5>Overview:</h5>
4465
4466<p>
Reid Spencer338ea092007-04-02 02:25:19 +0000[diff] [blame]4467The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4468values with an even number of bytes (positive multiple of 16 bits). These are
4469useful for performing operations on data that is not in the target's native
4470byte order.
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4471</p>
4472
4473<h5>Semantics:</h5>
4474
4475<p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4476The <tt>llvm.bswap.16.i16</tt> intrinsic returns an i16 value that has the high
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4477and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
4478intrinsic returns an i32 value that has the four bytes of the input i32
4479swapped, so that if the input bytes are numbered 0, 1, 2, 3 then the returned
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4480i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48.i48</tt>,
4481<tt>llvm.bswap.i64.i64</tt> and other intrinsics extend this concept to
4482additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4483</p>
4484
4485</div>
4486
4487<!-- _______________________________________________________________________ -->
4488<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4489 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4490</div>
4491
4492<div class="doc_text">
4493
4494<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4495<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
4496width. Not all targets support all bit widths however.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4497<pre>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4498 declare i32 @llvm.ctpop.i8 (i8 &lt;src&gt;)
4499 declare i32 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4500 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4501 declare i32 @llvm.ctpop.i64(i64 &lt;src&gt;)
4502 declare i32 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4503</pre>
4504
4505<h5>Overview:</h5>
4506
4507<p>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4508The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
4509value.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4510</p>
4511
4512<h5>Arguments:</h5>
4513
4514<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]4515The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4516integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4517</p>
4518
4519<h5>Semantics:</h5>
4520
4521<p>
4522The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
4523</p>
4524</div>
4525
4526<!-- _______________________________________________________________________ -->
4527<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]4528 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4529</div>
4530
4531<div class="doc_text">
4532
4533<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4534<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
4535integer bit width. Not all targets support all bit widths however.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4536<pre>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4537 declare i32 @llvm.ctlz.i8 (i8 &lt;src&gt;)
4538 declare i32 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4539 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4540 declare i32 @llvm.ctlz.i64(i64 &lt;src&gt;)
4541 declare i32 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4542</pre>
4543
4544<h5>Overview:</h5>
4545
4546<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4547The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
4548leading zeros in a variable.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4549</p>
4550
4551<h5>Arguments:</h5>
4552
4553<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]4554The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4555integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4556</p>
4557
4558<h5>Semantics:</h5>
4559
4560<p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4561The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
4562in 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]4563of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4564</p>
4565</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4566
4567
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4568
4569<!-- _______________________________________________________________________ -->
4570<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]4571 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4572</div>
4573
4574<div class="doc_text">
4575
4576<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4577<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
4578integer bit width. Not all targets support all bit widths however.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4579<pre>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4580 declare i32 @llvm.cttz.i8 (i8 &lt;src&gt;)
4581 declare i32 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4582 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4583 declare i32 @llvm.cttz.i64(i64 &lt;src&gt;)
4584 declare i32 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4585</pre>
4586
4587<h5>Overview:</h5>
4588
4589<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4590The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
4591trailing zeros.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4592</p>
4593
4594<h5>Arguments:</h5>
4595
4596<p>
4597The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4598integer type. The return type must match the argument type.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4599</p>
4600
4601<h5>Semantics:</h5>
4602
4603<p>
4604The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
4605in a variable. If the src == 0 then the result is the size in bits of the type
4606of src. For example, <tt>llvm.cttz(2) = 1</tt>.
4607</p>
4608</div>
4609
Reid Spencer497d93e2007-04-01 08:27:01 +0000[diff] [blame]4610<!-- _______________________________________________________________________ -->
4611<div class="doc_subsubsection">
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]4612 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4613</div>
4614
4615<div class="doc_text">
4616
4617<h5>Syntax:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]4618<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4619on any integer bit width.
4620<pre>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]4621 declare i17 @llvm.part.select.i17.i17 (i17 %val, i32 %loBit, i32 %hiBit)
4622 declare i29 @llvm.part.select.i29.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4623</pre>
4624
4625<h5>Overview:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]4626<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4627range of bits from an integer value and returns them in the same bit width as
4628the original value.</p>
4629
4630<h5>Arguments:</h5>
4631<p>The first argument, <tt>%val</tt> and the result may be integer types of
4632any bit width but they must have the same bit width. The second and third
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4633arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4634
4635<h5>Semantics:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]4636<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4637of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
4638<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
4639operates in forward mode.</p>
4640<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
4641right by <tt>%loBit</tt> bits and then ANDing it with a mask with
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4642only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
4643<ol>
4644 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
4645 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
4646 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
4647 to determine the number of bits to retain.</li>
4648 <li>A mask of the retained bits is created by shifting a -1 value.</li>
4649 <li>The mask is ANDed with <tt>%val</tt> to produce the result.
4650</ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4651<p>In reverse mode, a similar computation is made except that:</p>
4652<ol>
4653 <li>The bits selected wrap around to include both the highest and lowest bits.
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]4654 For example, part.select(i16 X, 4, 7) selects bits from X with a mask of
4655 0x00F0 (forwards case) while part.select(i16 X, 8, 3) selects bits from X
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4656 with a mask of 0xFF0F.</li>
4657 <li>The bits returned in the reverse case are reversed. So, if X has the value
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]4658 0x6ACF and we apply part.select(i16 X, 8, 3) to it, we get back the value
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4659 0x0A6F.</li>
4660</ol>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4661</div>
4662
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]4663<div class="doc_subsubsection">
4664 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
4665</div>
4666
4667<div class="doc_text">
4668
4669<h5>Syntax:</h5>
4670<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
4671on any integer bit width.
4672<pre>
4673 declare i17 @llvm.part.set.i17.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
4674 declare i29 @llvm.part.set.i29.i29.i9 (i29 %val, i9 %repl, i32 %lo, i32 %hi)
4675</pre>
4676
4677<h5>Overview:</h5>
4678<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
4679of bits in an integer value with another integer value. It returns the integer
4680with the replaced bits.</p>
4681
4682<h5>Arguments:</h5>
4683<p>The first argument, <tt>%val</tt> and the result may be integer types of
4684any bit width but they must have the same bit width. <tt>%val</tt> is the value
4685whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
4686integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
4687type since they specify only a bit index.</p>
4688
4689<h5>Semantics:</h5>
4690<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
4691of operation: forwards and reverse. If <tt>%lo</tt> is greater than
4692<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
4693operates in forward mode.</p>
4694<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
4695truncating it down to the size of the replacement area or zero extending it
4696up to that size.</p>
4697<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
4698are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
4699in <tt>%repl</tt> replaces the <tt>%lo</tt>th bit in <tt>%val</tt> and etc. up
4700to the <tt>%hi</tt>th bit.
4701<p>In reverse mode, a similar computation is made except that the bits replaced
4702wrap around to include both the highest and lowest bits. For example, if a
470316 bit value is being replaced then <tt>%lo=8</tt> and <tt>%hi=4</tt> would
Reid Spencer065cc7f2007-04-11 23:46:06 +0000[diff] [blame]4704cause these bits to be set: <tt>0xFF1F</tt>.</p>
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]4705<h5>Examples:</h5>
4706<pre>
Reid Spencerf0dbf642007-04-12 01:03:03 +0000[diff] [blame]4707 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
4708 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0x0060
4709 llvm.part.set(0xFFFF, 0, 8, 3) -&gt; 0x00F0
4710 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]4711</pre>
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]4712</div>
4713
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4714<!-- ======================================================================= -->
4715<div class="doc_subsection">
4716 <a name="int_debugger">Debugger Intrinsics</a>
4717</div>
4718
4719<div class="doc_text">
4720<p>
4721The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
4722are described in the <a
4723href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
4724Debugging</a> document.
4725</p>
4726</div>
4727
4728
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]4729<!-- ======================================================================= -->
4730<div class="doc_subsection">
4731 <a name="int_eh">Exception Handling Intrinsics</a>
4732</div>
4733
4734<div class="doc_text">
4735<p> The LLVM exception handling intrinsics (which all start with
4736<tt>llvm.eh.</tt> prefix), are described in the <a
4737href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
4738Handling</a> document. </p>
4739</div>
4740
4741
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4742<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4743<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]4744<address>
4745 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
4746 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
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4748 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!" /></a>
4749
4750 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]4751 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]4752 Last modified: $Date$
4753</address>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4754</body>
4755</html>