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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 6f9896fcc81a1128b5f436d1763cc6213745adf1 / . / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
Reid Spencer3921c742004-08-26 20:44:00 +0000[diff] [blame]6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
8 <meta name="description"
9 content="LLVM Assembly Language Reference Manual.">
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11</head>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]14
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]15<div class="doc_title"> LLVM Language Reference Manual </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a></li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]24 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]25 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]26 <li><a href="#functionstructure">Functions</a></li>
Anton Korobeynikovc6c98af2007-04-29 18:02:48 +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
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame^]594 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
595
596 <dd>On ELF, protected visibility indicates that the symbol will be placed in
597 the dynamic symbol table, but that references within the defining module will
598 bind to the local symbol. That is, the symbol cannot be overridden by another
599 module.
600 </dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]601</dl>
602
603</div>
604
605<!-- ======================================================================= -->
606<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]607 <a name="globalvars">Global Variables</a>
608</div>
609
610<div class="doc_text">
611
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]612<p>Global variables define regions of memory allocated at compilation time
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]613instead of run-time. Global variables may optionally be initialized, may have
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]614an explicit section to be placed in, and may have an optional explicit alignment
615specified. A variable may be defined as "thread_local", which means that it
616will not be shared by threads (each thread will have a separated copy of the
617variable). A variable may be defined as a global "constant," which indicates
618that the contents of the variable will <b>never</b> be modified (enabling better
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]619optimization, allowing the global data to be placed in the read-only section of
620an executable, etc). Note that variables that need runtime initialization
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]621cannot be marked "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]622
623<p>
624LLVM explicitly allows <em>declarations</em> of global variables to be marked
625constant, even if the final definition of the global is not. This capability
626can be used to enable slightly better optimization of the program, but requires
627the language definition to guarantee that optimizations based on the
628'constantness' are valid for the translation units that do not include the
629definition.
630</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]631
632<p>As SSA values, global variables define pointer values that are in
633scope (i.e. they dominate) all basic blocks in the program. Global
634variables always define a pointer to their "content" type because they
635describe a region of memory, and all memory objects in LLVM are
636accessed through pointers.</p>
637
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]638<p>LLVM allows an explicit section to be specified for globals. If the target
639supports it, it will emit globals to the section specified.</p>
640
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]641<p>An explicit alignment may be specified for a global. If not present, or if
642the alignment is set to zero, the alignment of the global is set by the target
643to whatever it feels convenient. If an explicit alignment is specified, the
644global is forced to have at least that much alignment. All alignments must be
645a power of 2.</p>
646
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]647<p>For example, the following defines a global with an initializer, section,
648 and alignment:</p>
649
650<pre>
651 %G = constant float 1.0, section "foo", align 4
652</pre>
653
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]654</div>
655
656
657<!-- ======================================================================= -->
658<div class="doc_subsection">
659 <a name="functionstructure">Functions</a>
660</div>
661
662<div class="doc_text">
663
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]664<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
665an optional <a href="#linkage">linkage type</a>, an optional
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]666<a href="#visibility">visibility style</a>, an optional
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]667<a href="#callingconv">calling convention</a>, a return type, an optional
668<a href="#paramattrs">parameter attribute</a> for the return type, a function
669name, a (possibly empty) argument list (each with optional
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]670<a href="#paramattrs">parameter attributes</a>), an optional section, an
671optional alignment, an opening curly brace, a list of basic blocks, and a
672closing curly brace.
673
674LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
675optional <a href="#linkage">linkage type</a>, an optional
676<a href="#visibility">visibility style</a>, an optional
677<a href="#callingconv">calling convention</a>, a return type, an optional
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]678<a href="#paramattrs">parameter attribute</a> for the return type, a function
679name, a possibly empty list of arguments, and an optional alignment.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]680
681<p>A function definition contains a list of basic blocks, forming the CFG for
682the function. Each basic block may optionally start with a label (giving the
683basic block a symbol table entry), contains a list of instructions, and ends
684with a <a href="#terminators">terminator</a> instruction (such as a branch or
685function return).</p>
686
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]687<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]688executed on entrance to the function, and it is not allowed to have predecessor
689basic blocks (i.e. there can not be any branches to the entry block of a
690function). Because the block can have no predecessors, it also cannot have any
691<a href="#i_phi">PHI nodes</a>.</p>
692
693<p>LLVM functions are identified by their name and type signature. Hence, two
694functions with the same name but different parameter lists or return values are
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]695considered different functions, and LLVM will resolve references to each
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]696appropriately.</p>
697
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]698<p>LLVM allows an explicit section to be specified for functions. If the target
699supports it, it will emit functions to the section specified.</p>
700
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]701<p>An explicit alignment may be specified for a function. If not present, or if
702the alignment is set to zero, the alignment of the function is set by the target
703to whatever it feels convenient. If an explicit alignment is specified, the
704function is forced to have at least that much alignment. All alignments must be
705a power of 2.</p>
706
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]707</div>
708
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]709
710<!-- ======================================================================= -->
711<div class="doc_subsection">
712 <a name="aliasstructure">Aliases</a>
713</div>
714<div class="doc_text">
715 <p>Aliases act as "second name" for the aliasee value (which can be either
Anton Korobeynikova80e1182007-04-28 13:45:00 +0000[diff] [blame]716 function or global variable or bitcast of global value). Aliases may have an
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]717 optional <a href="#linkage">linkage type</a>, and an
718 optional <a href="#visibility">visibility style</a>.</p>
719
720 <h5>Syntax:</h5>
721
722 <pre>
723 @&lt;Name&gt; = [Linkage] [Visibility] alias &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
724 </pre>
725
726</div>
727
728
729
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]730<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]731<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
732<div class="doc_text">
733 <p>The return type and each parameter of a function type may have a set of
734 <i>parameter attributes</i> associated with them. Parameter attributes are
735 used to communicate additional information about the result or parameters of
736 a function. Parameter attributes are considered to be part of the function
737 type so two functions types that differ only by the parameter attributes
738 are different function types.</p>
739
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]740 <p>Parameter attributes are simple keywords that follow the type specified. If
741 multiple parameter attributes are needed, they are space separated. For
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]742 example:</p><pre>
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]743 %someFunc = i16 (i8 sext %someParam) zext
744 %someFunc = i16 (i8 zext %someParam) zext</pre>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]745 <p>Note that the two function types above are unique because the parameter has
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]746 a different attribute (sext in the first one, zext in the second). Also note
747 that the attribute for the function result (zext) comes immediately after the
748 argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]749
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]750 <p>Currently, only the following parameter attributes are defined:</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]751 <dl>
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]752 <dt><tt>zext</tt></dt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]753 <dd>This indicates that the parameter should be zero extended just before
754 a call to this function.</dd>
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]755 <dt><tt>sext</tt></dt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]756 <dd>This indicates that the parameter should be sign extended just before
757 a call to this function.</dd>
Anton Korobeynikov34d6dea2007-01-28 14:30:45 +0000[diff] [blame]758 <dt><tt>inreg</tt></dt>
759 <dd>This indicates that the parameter should be placed in register (if
Anton Korobeynikov66a8c8c2007-01-28 15:27:21 +0000[diff] [blame]760 possible) during assembling function call. Support for this attribute is
761 target-specific</dd>
Anton Korobeynikov34d6dea2007-01-28 14:30:45 +0000[diff] [blame]762 <dt><tt>sret</tt></dt>
Anton Korobeynikov66a8c8c2007-01-28 15:27:21 +0000[diff] [blame]763 <dd>This indicates that the parameter specifies the address of a structure
Reid Spencer67606122007-03-22 02:02:11 +0000[diff] [blame]764 that is the return value of the function in the source program.</dd>
Reid Spencer2dc52012007-03-22 02:18:56 +0000[diff] [blame]765 <dt><tt>noreturn</tt></dt>
766 <dd>This function attribute indicates that the function never returns. This
767 indicates to LLVM that every call to this function should be treated as if
768 an <tt>unreachable</tt> instruction immediately followed the call.</dd>
Reid Spencer67606122007-03-22 02:02:11 +0000[diff] [blame]769 <dt><tt>nounwind</tt></dt>
770 <dd>This function attribute indicates that the function type does not use
771 the unwind instruction and does not allow stack unwinding to propagate
772 through it.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]773 </dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]774
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]775</div>
776
777<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]778<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]779 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]780</div>
781
782<div class="doc_text">
783<p>
784Modules may contain "module-level inline asm" blocks, which corresponds to the
785GCC "file scope inline asm" blocks. These blocks are internally concatenated by
786LLVM and treated as a single unit, but may be separated in the .ll file if
787desired. The syntax is very simple:
788</p>
789
790<div class="doc_code"><pre>
Chris Lattner52599e12006-01-24 00:37:20 +0000[diff] [blame]791 module asm "inline asm code goes here"
792 module asm "more can go here"
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]793</pre></div>
794
795<p>The strings can contain any character by escaping non-printable characters.
796 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
797 for the number.
798</p>
799
800<p>
801 The inline asm code is simply printed to the machine code .s file when
802 assembly code is generated.
803</p>
804</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]805
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]806<!-- ======================================================================= -->
807<div class="doc_subsection">
808 <a name="datalayout">Data Layout</a>
809</div>
810
811<div class="doc_text">
812<p>A module may specify a target specific data layout string that specifies how
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]813data is to be laid out in memory. The syntax for the data layout is simply:</p>
814<pre> target datalayout = "<i>layout specification</i>"</pre>
815<p>The <i>layout specification</i> consists of a list of specifications
816separated by the minus sign character ('-'). Each specification starts with a
817letter and may include other information after the letter to define some
818aspect of the data layout. The specifications accepted are as follows: </p>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]819<dl>
820 <dt><tt>E</tt></dt>
821 <dd>Specifies that the target lays out data in big-endian form. That is, the
822 bits with the most significance have the lowest address location.</dd>
823 <dt><tt>e</tt></dt>
824 <dd>Specifies that hte target lays out data in little-endian form. That is,
825 the bits with the least significance have the lowest address location.</dd>
826 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
827 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
828 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
829 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
830 too.</dd>
831 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
832 <dd>This specifies the alignment for an integer type of a given bit
833 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
834 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
835 <dd>This specifies the alignment for a vector type of a given bit
836 <i>size</i>.</dd>
837 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
838 <dd>This specifies the alignment for a floating point type of a given bit
839 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
840 (double).</dd>
841 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
842 <dd>This specifies the alignment for an aggregate type of a given bit
843 <i>size</i>.</dd>
844</dl>
845<p>When constructing the data layout for a given target, LLVM starts with a
846default set of specifications which are then (possibly) overriden by the
847specifications in the <tt>datalayout</tt> keyword. The default specifications
848are given in this list:</p>
849<ul>
850 <li><tt>E</tt> - big endian</li>
851 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
852 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
853 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
854 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
855 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
856 <li><tt>i64:32:64</tt> - i64 has abi alignment of 32-bits but preferred
857 alignment of 64-bits</li>
858 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
859 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
860 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
861 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
862 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
863</ul>
864<p>When llvm is determining the alignment for a given type, it uses the
865following rules:
866<ol>
867 <li>If the type sought is an exact match for one of the specifications, that
868 specification is used.</li>
869 <li>If no match is found, and the type sought is an integer type, then the
870 smallest integer type that is larger than the bitwidth of the sought type is
871 used. If none of the specifications are larger than the bitwidth then the the
872 largest integer type is used. For example, given the default specifications
873 above, the i7 type will use the alignment of i8 (next largest) while both
874 i65 and i256 will use the alignment of i64 (largest specified).</li>
875 <li>If no match is found, and the type sought is a vector type, then the
876 largest vector type that is smaller than the sought vector type will be used
877 as a fall back. This happens because <128 x double> can be implemented in
878 terms of 64 <2 x double>, for example.</li>
879</ol>
880</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]881
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]882<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]883<div class="doc_section"> <a name="typesystem">Type System</a> </div>
884<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]885
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]886<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]887
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]888<p>The LLVM type system is one of the most important features of the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]889intermediate representation. Being typed enables a number of
890optimizations to be performed on the IR directly, without having to do
891extra analyses on the side before the transformation. A strong type
892system makes it easier to read the generated code and enables novel
893analyses and transformations that are not feasible to perform on normal
894three address code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]895
896</div>
897
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]898<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]899<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]900<div class="doc_text">
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]901<p>The primitive types are the fundamental building blocks of the LLVM
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]902system. The current set of primitive types is as follows:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]903
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]904<table class="layout">
905 <tr class="layout">
906 <td class="left">
907 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]908 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]909 <tr><th>Type</th><th>Description</th></tr>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]910 <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]911 <tr><td><tt>i8</tt></td><td>8-bit value</td></tr>
912 <tr><td><tt>i32</tt></td><td>32-bit value</td></tr>
Misha Brukmancfa87bc2005-04-22 18:02:52 +0000[diff] [blame]913 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]914 <tr><td><tt>label</tt></td><td>Branch destination</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]915 </tbody>
916 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]917 </td>
918 <td class="right">
919 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]920 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]921 <tr><th>Type</th><th>Description</th></tr>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]922 <tr><td><tt>i1</tt></td><td>True or False value</td></tr>
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]923 <tr><td><tt>i16</tt></td><td>16-bit value</td></tr>
924 <tr><td><tt>i64</tt></td><td>64-bit value</td></tr>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]925 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]926 </tbody>
927 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]928 </td>
929 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]930</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]931</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]932
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]933<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]934<div class="doc_subsubsection"> <a name="t_classifications">Type
935Classifications</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]936<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]937<p>These different primitive types fall into a few useful
938classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]939
940<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]941 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]942 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]943 <tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]944 <td><a name="t_integer">integer</a></td>
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]945 <td><tt>i1, i8, i16, i32, i64</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]946 </tr>
947 <tr>
948 <td><a name="t_floating">floating point</a></td>
949 <td><tt>float, double</tt></td>
950 </tr>
951 <tr>
952 <td><a name="t_firstclass">first class</a></td>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]953 <td><tt>i1, i8, i16, i32, i64, float, double, <br/>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]954 <a href="#t_pointer">pointer</a>,<a href="#t_vector">vector</a></tt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]955 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]956 </tr>
957 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]958</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]959
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]960<p>The <a href="#t_firstclass">first class</a> types are perhaps the
961most important. Values of these types are the only ones which can be
962produced by instructions, passed as arguments, or used as operands to
963instructions. This means that all structures and arrays must be
964manipulated either by pointer or by component.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]965</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]966
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]967<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]968<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]969
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]970<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]971
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]972<p>The real power in LLVM comes from the derived types in the system.
973This is what allows a programmer to represent arrays, functions,
974pointers, and other useful types. Note that these derived types may be
975recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]976
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]977</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]978
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]979<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]980<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]981
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]982<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]983
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]984<h5>Overview:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]985
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]986<p>The array type is a very simple derived type that arranges elements
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]987sequentially in memory. The array type requires a size (number of
988elements) and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]989
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]990<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]991
992<pre>
993 [&lt;# elements&gt; x &lt;elementtype&gt;]
994</pre>
995
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]996<p>The number of elements is a constant integer value; elementtype may
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]997be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]998
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]999<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1000<table class="layout">
1001 <tr class="layout">
1002 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1003 <tt>[40 x i32 ]</tt><br/>
1004 <tt>[41 x i32 ]</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1005 <tt>[40 x i8]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1006 </td>
1007 <td class="left">
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1008 Array of 40 32-bit integer values.<br/>
1009 Array of 41 32-bit integer values.<br/>
1010 Array of 40 8-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1011 </td>
1012 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1013</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1014<p>Here are some examples of multidimensional arrays:</p>
1015<table class="layout">
1016 <tr class="layout">
1017 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1018 <tt>[3 x [4 x i32]]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1019 <tt>[12 x [10 x float]]</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1020 <tt>[2 x [3 x [4 x i16]]]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1021 </td>
1022 <td class="left">
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1023 3x4 array of 32-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1024 12x10 array of single precision floating point values.<br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1025 2x3x4 array of 16-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1026 </td>
1027 </tr>
1028</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1029
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1030<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1031length array. Normally, accesses past the end of an array are undefined in
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1032LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1033As a special case, however, zero length arrays are recognized to be variable
1034length. This allows implementation of 'pascal style arrays' with the LLVM
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1035type "{ i32, [0 x float]}", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1036
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1037</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1038
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1039<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1040<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1041<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1042<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1043<p>The function type can be thought of as a function signature. It
1044consists of a return type and a list of formal parameter types.
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]1045Function types are usually used to build virtual function tables
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1046(which are structures of pointers to functions), for indirect function
1047calls, and when defining a function.</p>
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]1048<p>
1049The return type of a function type cannot be an aggregate type.
1050</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1051<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1052<pre> &lt;returntype&gt; (&lt;parameter list&gt;)<br></pre>
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1053<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]1054specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1055which indicates that the function takes a variable number of arguments.
1056Variable argument functions can access their arguments with the <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1057 href="#int_varargs">variable argument handling intrinsic</a> functions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1058<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1059<table class="layout">
1060 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1061 <td class="left"><tt>i32 (i32)</tt></td>
1062 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1063 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1064 </tr><tr class="layout">
Reid Spencer7bf214d2007-01-15 18:28:34 +0000[diff] [blame]1065 <td class="left"><tt>float&nbsp;(i16&nbsp;sext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1066 </tt></td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1067 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1068 an <tt>i16</tt> that should be sign extended and a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1069 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1070 <tt>float</tt>.
1071 </td>
1072 </tr><tr class="layout">
1073 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1074 <td class="left">A vararg function that takes at least one
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1075 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1076 which returns an integer. This is the signature for <tt>printf</tt> in
1077 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1078 </td>
1079 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1080</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1081
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1082</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1083<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1084<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1085<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1086<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1087<p>The structure type is used to represent a collection of data members
1088together in memory. The packing of the field types is defined to match
1089the ABI of the underlying processor. The elements of a structure may
1090be any type that has a size.</p>
1091<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1092and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1093field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1094instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1095<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1096<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1097<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1098<table class="layout">
1099 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1100 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1101 <td class="left">A triple of three <tt>i32</tt> values</td>
1102 </tr><tr class="layout">
1103 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1104 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1105 second element is a <a href="#t_pointer">pointer</a> to a
1106 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1107 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1108 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1109</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1110</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1111
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1112<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1113<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1114</div>
1115<div class="doc_text">
1116<h5>Overview:</h5>
1117<p>The packed structure type is used to represent a collection of data members
1118together in memory. There is no padding between fields. Further, the alignment
1119of a packed structure is 1 byte. The elements of a packed structure may
1120be any type that has a size.</p>
1121<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1122and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1123field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1124instruction.</p>
1125<h5>Syntax:</h5>
1126<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1127<h5>Examples:</h5>
1128<table class="layout">
1129 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1130 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1131 <td class="left">A triple of three <tt>i32</tt> values</td>
1132 </tr><tr class="layout">
1133 <td class="left"><tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}&nbsp;&gt;</tt></td>
1134 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1135 second element is a <a href="#t_pointer">pointer</a> to a
1136 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1137 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1138 </tr>
1139</table>
1140</div>
1141
1142<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1143<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1144<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1145<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1146<p>As in many languages, the pointer type represents a pointer or
1147reference to another object, which must live in memory.</p>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1148<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1149<pre> &lt;type&gt; *<br></pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1150<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1151<table class="layout">
1152 <tr class="layout">
1153 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1154 <tt>[4x i32]*</tt><br/>
1155 <tt>i32 (i32 *) *</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1156 </td>
1157 <td class="left">
1158 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]1159 four <tt>i32</tt> values<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1160 A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1161 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
1162 <tt>i32</tt>.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1163 </td>
1164 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1165</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1166</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1167
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1168<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1169<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1170<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1171
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1172<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1173
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1174<p>A vector type is a simple derived type that represents a vector
1175of elements. Vector types are used when multiple primitive data
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1176are operated in parallel using a single instruction (SIMD).
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1177A vector type requires a size (number of
Chris Lattnerb8d172f2005-11-10 01:44:22 +0000[diff] [blame]1178elements) and an underlying primitive data type. Vectors must have a power
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1179of two length (1, 2, 4, 8, 16 ...). Vector types are
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1180considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1181
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1182<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1183
1184<pre>
1185 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1186</pre>
1187
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1188<p>The number of elements is a constant integer value; elementtype may
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]1189be any integer or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1190
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1191<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1192
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1193<table class="layout">
1194 <tr class="layout">
1195 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1196 <tt>&lt;4 x i32&gt;</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1197 <tt>&lt;8 x float&gt;</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1198 <tt>&lt;2 x i64&gt;</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1199 </td>
1200 <td class="left">
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1201 Vector of 4 32-bit integer values.<br/>
1202 Vector of 8 floating-point values.<br/>
1203 Vector of 2 64-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1204 </td>
1205 </tr>
1206</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1207</div>
1208
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1209<!-- _______________________________________________________________________ -->
1210<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1211<div class="doc_text">
1212
1213<h5>Overview:</h5>
1214
1215<p>Opaque types are used to represent unknown types in the system. This
1216corresponds (for example) to the C notion of a foward declared structure type.
1217In LLVM, opaque types can eventually be resolved to any type (not just a
1218structure type).</p>
1219
1220<h5>Syntax:</h5>
1221
1222<pre>
1223 opaque
1224</pre>
1225
1226<h5>Examples:</h5>
1227
1228<table class="layout">
1229 <tr class="layout">
1230 <td class="left">
1231 <tt>opaque</tt>
1232 </td>
1233 <td class="left">
1234 An opaque type.<br/>
1235 </td>
1236 </tr>
1237</table>
1238</div>
1239
1240
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1241<!-- *********************************************************************** -->
1242<div class="doc_section"> <a name="constants">Constants</a> </div>
1243<!-- *********************************************************************** -->
1244
1245<div class="doc_text">
1246
1247<p>LLVM has several different basic types of constants. This section describes
1248them all and their syntax.</p>
1249
1250</div>
1251
1252<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1253<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1254
1255<div class="doc_text">
1256
1257<dl>
1258 <dt><b>Boolean constants</b></dt>
1259
1260 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1261 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1262 </dd>
1263
1264 <dt><b>Integer constants</b></dt>
1265
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1266 <dd>Standard integers (such as '4') are constants of the <a
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1267 href="#t_integer">integer</a> type. Negative numbers may be used with
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1268 integer types.
1269 </dd>
1270
1271 <dt><b>Floating point constants</b></dt>
1272
1273 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1274 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1275 notation (see below). Floating point constants must have a <a
1276 href="#t_floating">floating point</a> type. </dd>
1277
1278 <dt><b>Null pointer constants</b></dt>
1279
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1280 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1281 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1282
1283</dl>
1284
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1285<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1286of floating point constants. For example, the form '<tt>double
12870x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
12884.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1289(and the only time that they are generated by the disassembler) is when a
1290floating point constant must be emitted but it cannot be represented as a
1291decimal floating point number. For example, NaN's, infinities, and other
1292special values are represented in their IEEE hexadecimal format so that
1293assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1294
1295</div>
1296
1297<!-- ======================================================================= -->
1298<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1299</div>
1300
1301<div class="doc_text">
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1302<p>Aggregate constants arise from aggregation of simple constants
1303and smaller aggregate constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1304
1305<dl>
1306 <dt><b>Structure constants</b></dt>
1307
1308 <dd>Structure constants are represented with notation similar to structure
1309 type definitions (a comma separated list of elements, surrounded by braces
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1310 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* %G }</tt>",
1311 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]1312 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1313 types of elements must match those specified by the type.
1314 </dd>
1315
1316 <dt><b>Array constants</b></dt>
1317
1318 <dd>Array constants are represented with notation similar to array type
1319 definitions (a comma separated list of elements, surrounded by square brackets
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1320 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1321 constants must have <a href="#t_array">array type</a>, and the number and
1322 types of elements must match those specified by the type.
1323 </dd>
1324
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1325 <dt><b>Vector constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1326
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1327 <dd>Vector constants are represented with notation similar to vector type
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1328 definitions (a comma separated list of elements, surrounded by
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1329 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]1330 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1331 href="#t_vector">vector type</a>, and the number and types of elements must
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1332 match those specified by the type.
1333 </dd>
1334
1335 <dt><b>Zero initialization</b></dt>
1336
1337 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1338 value to zero of <em>any</em> type, including scalar and aggregate types.
1339 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]1340 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1341 initializers.
1342 </dd>
1343</dl>
1344
1345</div>
1346
1347<!-- ======================================================================= -->
1348<div class="doc_subsection">
1349 <a name="globalconstants">Global Variable and Function Addresses</a>
1350</div>
1351
1352<div class="doc_text">
1353
1354<p>The addresses of <a href="#globalvars">global variables</a> and <a
1355href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1356constants. These constants are explicitly referenced when the <a
1357href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1358href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1359file:</p>
1360
1361<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1362 %X = global i32 17
1363 %Y = global i32 42
1364 %Z = global [2 x i32*] [ i32* %X, i32* %Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1365</pre>
1366
1367</div>
1368
1369<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1370<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1371<div class="doc_text">
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1372 <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]1373 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1374 a constant is permitted.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1375
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1376 <p>Undefined values indicate to the compiler that the program is well defined
1377 no matter what value is used, giving the compiler more freedom to optimize.
1378 </p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1379</div>
1380
1381<!-- ======================================================================= -->
1382<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1383</div>
1384
1385<div class="doc_text">
1386
1387<p>Constant expressions are used to allow expressions involving other constants
1388to be used as constants. Constant expressions may be of any <a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1389href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1390that does not have side effects (e.g. load and call are not supported). The
1391following is the syntax for constant expressions:</p>
1392
1393<dl>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1394 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1395 <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]1396 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1397
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1398 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1399 <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]1400 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]1401
1402 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1403 <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]1404 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]1405
1406 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1407 <dd>Truncate a floating point constant to another floating point type. The
1408 size of CST must be larger than the size of TYPE. Both types must be
1409 floating point.</dd>
1410
1411 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1412 <dd>Floating point extend a constant to another type. The size of CST must be
1413 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1414
1415 <dt><b><tt>fp2uint ( CST to TYPE )</tt></b></dt>
1416 <dd>Convert a floating point constant to the corresponding unsigned integer
1417 constant. TYPE must be an integer type. CST must be floating point. If the
1418 value won't fit in the integer type, the results are undefined.</dd>
1419
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1420 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1421 <dd>Convert a floating point constant to the corresponding signed integer
1422 constant. TYPE must be an integer type. CST must be floating point. If the
1423 value won't fit in the integer type, the results are undefined.</dd>
1424
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1425 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1426 <dd>Convert an unsigned integer constant to the corresponding floating point
1427 constant. TYPE must be floating point. CST must be of integer type. If the
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]1428 value won't fit in the floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1429
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1430 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1431 <dd>Convert a signed integer constant to the corresponding floating point
1432 constant. TYPE must be floating point. CST must be of integer type. If the
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]1433 value won't fit in the floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1434
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]1435 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1436 <dd>Convert a pointer typed constant to the corresponding integer constant
1437 TYPE must be an integer type. CST must be of pointer type. The CST value is
1438 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1439
1440 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1441 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1442 pointer type. CST must be of integer type. The CST value is zero extended,
1443 truncated, or unchanged to make it fit in a pointer size. This one is
1444 <i>really</i> dangerous!</dd>
1445
1446 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1447 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1448 identical (same number of bits). The conversion is done as if the CST value
1449 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]1450 with this operator, just the type. This can be used for conversion of
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1451 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]1452 pointers it is only valid to cast to another pointer type.
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1453 </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1454
1455 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1456
1457 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1458 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1459 instruction, the index list may have zero or more indexes, which are required
1460 to make sense for the type of "CSTPTR".</dd>
1461
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1462 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1463
1464 <dd>Perform the <a href="#i_select">select operation</a> on
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1465 constants.</dd>
1466
1467 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1468 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1469
1470 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1471 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1472
1473 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1474
1475 <dd>Perform the <a href="#i_extractelement">extractelement
1476 operation</a> on constants.
1477
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1478 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1479
1480 <dd>Perform the <a href="#i_insertelement">insertelement
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1481 operation</a> on constants.</dd>
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1482
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1483
1484 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1485
1486 <dd>Perform the <a href="#i_shufflevector">shufflevector
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1487 operation</a> on constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1488
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1489 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1490
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1491 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1492 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1493 binary</a> operations. The constraints on operands are the same as those for
1494 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1495 values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1496</dl>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1497</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]1498
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1499<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1500<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1501<!-- *********************************************************************** -->
1502
1503<!-- ======================================================================= -->
1504<div class="doc_subsection">
1505<a name="inlineasm">Inline Assembler Expressions</a>
1506</div>
1507
1508<div class="doc_text">
1509
1510<p>
1511LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1512Module-Level Inline Assembly</a>) through the use of a special value. This
1513value represents the inline assembler as a string (containing the instructions
1514to emit), a list of operand constraints (stored as a string), and a flag that
1515indicates whether or not the inline asm expression has side effects. An example
1516inline assembler expression is:
1517</p>
1518
1519<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1520 i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1521</pre>
1522
1523<p>
1524Inline assembler expressions may <b>only</b> be used as the callee operand of
1525a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1526</p>
1527
1528<pre>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]1529 %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]1530</pre>
1531
1532<p>
1533Inline asms with side effects not visible in the constraint list must be marked
1534as having side effects. This is done through the use of the
1535'<tt>sideeffect</tt>' keyword, like so:
1536</p>
1537
1538<pre>
1539 call void asm sideeffect "eieio", ""()
1540</pre>
1541
1542<p>TODO: The format of the asm and constraints string still need to be
1543documented here. Constraints on what can be done (e.g. duplication, moving, etc
1544need to be documented).
1545</p>
1546
1547</div>
1548
1549<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1550<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1551<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1552
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1553<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1554
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1555<p>The LLVM instruction set consists of several different
1556classifications of instructions: <a href="#terminators">terminator
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1557instructions</a>, <a href="#binaryops">binary instructions</a>,
1558<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1559 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1560instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1561
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1562</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1563
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1564<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1565<div class="doc_subsection"> <a name="terminators">Terminator
1566Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1567
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1568<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1569
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1570<p>As mentioned <a href="#functionstructure">previously</a>, every
1571basic block in a program ends with a "Terminator" instruction, which
1572indicates which block should be executed after the current block is
1573finished. These terminator instructions typically yield a '<tt>void</tt>'
1574value: they produce control flow, not values (the one exception being
1575the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1576<p>There are six different terminator instructions: the '<a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1577 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1578instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1579the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1580 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1581 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1582
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1583</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1584
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1585<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1586<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1587Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1588<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1589<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1590<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]1591 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1592</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1593<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1594<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1595value) from a function back to the caller.</p>
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]1596<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1597returns a value and then causes control flow, and one that just causes
1598control flow to occur.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1599<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1600<p>The '<tt>ret</tt>' instruction may return any '<a
1601 href="#t_firstclass">first class</a>' type. Notice that a function is
1602not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
1603instruction inside of the function that returns a value that does not
1604match the return type of the function.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1605<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1606<p>When the '<tt>ret</tt>' instruction is executed, control flow
1607returns back to the calling function's context. If the caller is a "<a
John Criswellfa081872004-06-25 15:16:57 +0000[diff] [blame]1608 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1609the instruction after the call. If the caller was an "<a
1610 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1611at the beginning of the "normal" destination block. If the instruction
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1612returns a value, that value shall set the call or invoke instruction's
1613return value.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1614<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1615<pre> ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1616 ret void <i>; Return from a void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1617</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1618</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1619<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1620<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1621<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1622<h5>Syntax:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1623<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]1624</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1625<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1626<p>The '<tt>br</tt>' instruction is used to cause control flow to
1627transfer to a different basic block in the current function. There are
1628two forms of this instruction, corresponding to a conditional branch
1629and an unconditional branch.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1630<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1631<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1632single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1633unconditional form of the '<tt>br</tt>' instruction takes a single
1634'<tt>label</tt>' value as a target.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1635<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1636<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1637argument is evaluated. If the value is <tt>true</tt>, control flows
1638to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1639control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1640<h5>Example:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1641<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]1642 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]1643</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1644<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1645<div class="doc_subsubsection">
1646 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1647</div>
1648
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1649<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1650<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1651
1652<pre>
1653 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1654</pre>
1655
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1656<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1657
1658<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1659several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1660instruction, allowing a branch to occur to one of many possible
1661destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1662
1663
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1664<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1665
1666<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1667comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1668an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1669table is not allowed to contain duplicate constant entries.</p>
1670
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1671<h5>Semantics:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1672
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1673<p>The <tt>switch</tt> instruction specifies a table of values and
1674destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1675table is searched for the given value. If the value is found, control flow is
1676transfered to the corresponding destination; otherwise, control flow is
1677transfered to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1678
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1679<h5>Implementation:</h5>
1680
1681<p>Depending on properties of the target machine and the particular
1682<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1683ways. For example, it could be generated as a series of chained conditional
1684branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1685
1686<h5>Example:</h5>
1687
1688<pre>
1689 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1690 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1691 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1692
1693 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1694 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1695
1696 <i>; Implement a jump table:</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1697 switch i32 %val, label %otherwise [ i32 0, label %onzero
1698 i32 1, label %onone
1699 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1700</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1701</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1702
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1703<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1704<div class="doc_subsubsection">
1705 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1706</div>
1707
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1708<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1709
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1710<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1711
1712<pre>
1713 &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]1714 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1715</pre>
1716
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1717<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1718
1719<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1720function, with the possibility of control flow transfer to either the
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1721'<tt>normal</tt>' label or the
1722'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1723"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1724"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1725href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
1726continued at the dynamically nearest "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1727
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1728<h5>Arguments:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1729
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1730<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1731
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1732<ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1733 <li>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]1734 The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1735 convention</a> the call should use. If none is specified, the call defaults
1736 to using C calling conventions.
1737 </li>
1738 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1739 function value being invoked. In most cases, this is a direct function
1740 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1741 an arbitrary pointer to function value.
1742 </li>
1743
1744 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1745 function to be invoked. </li>
1746
1747 <li>'<tt>function args</tt>': argument list whose types match the function
1748 signature argument types. If the function signature indicates the function
1749 accepts a variable number of arguments, the extra arguments can be
1750 specified. </li>
1751
1752 <li>'<tt>normal label</tt>': the label reached when the called function
1753 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1754
1755 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1756 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1757
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1758</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1759
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1760<h5>Semantics:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1761
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1762<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1763href="#i_call">call</a></tt>' instruction in most regards. The primary
1764difference is that it establishes an association with a label, which is used by
1765the runtime library to unwind the stack.</p>
1766
1767<p>This instruction is used in languages with destructors to ensure that proper
1768cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1769exception. Additionally, this is important for implementation of
1770'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1771
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1772<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1773<pre>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1774 %retval = invoke i32 %Test(i32 15) to label %Continue
1775 unwind label %TestCleanup <i>; {i32}:retval set</i>
1776 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Test(i32 15) to label %Continue
1777 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1778</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1779</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1780
1781
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1782<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1783
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1784<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1785Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1786
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1787<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1788
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1789<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1790<pre>
1791 unwind
1792</pre>
1793
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1794<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1795
1796<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
1797at the first callee in the dynamic call stack which used an <a
1798href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
1799primarily used to implement exception handling.</p>
1800
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1801<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1802
1803<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
1804immediately halt. The dynamic call stack is then searched for the first <a
1805href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
1806execution continues at the "exceptional" destination block specified by the
1807<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
1808dynamic call chain, undefined behavior results.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1809</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1810
1811<!-- _______________________________________________________________________ -->
1812
1813<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
1814Instruction</a> </div>
1815
1816<div class="doc_text">
1817
1818<h5>Syntax:</h5>
1819<pre>
1820 unreachable
1821</pre>
1822
1823<h5>Overview:</h5>
1824
1825<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
1826instruction is used to inform the optimizer that a particular portion of the
1827code is not reachable. This can be used to indicate that the code after a
1828no-return function cannot be reached, and other facts.</p>
1829
1830<h5>Semantics:</h5>
1831
1832<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
1833</div>
1834
1835
1836
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1837<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1838<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1839<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1840<p>Binary operators are used to do most of the computation in a
1841program. They require two operands, execute an operation on them, and
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1842produce a single value. The operands might represent
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1843multiple 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]1844The result value of a binary operator is not
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1845necessarily the same type as its operands.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1846<p>There are several different binary operators:</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1847</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1848<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1849<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
1850Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1851<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1852<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1853<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]1854</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1855<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1856<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1857<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1858<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1859 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1860 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]1861Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1862<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1863<p>The value produced is the integer or floating point sum of the two
1864operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1865<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1866<pre> &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1867</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1868</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1869<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1870<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
1871Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1872<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1873<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1874<pre> &lt;result&gt; = 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]1875</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1876<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1877<p>The '<tt>sub</tt>' instruction returns the difference of its two
1878operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1879<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
1880instruction present in most other intermediate representations.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1881<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1882<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1883 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1884values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1885This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1886Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1887<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1888<p>The value produced is the integer or floating point difference of
1889the two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1890<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1891<pre> &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
1892 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1893</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1894</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1895<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1896<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
1897Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1898<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1899<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1900<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]1901</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1902<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1903<p>The '<tt>mul</tt>' instruction returns the product of its two
1904operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1905<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1906<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1907 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1908values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1909This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1910Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1911<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1912<p>The value produced is the integer or floating point product of the
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1913two operands.</p>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1914<p>Because the operands are the same width, the result of an integer
1915multiplication is the same whether the operands should be deemed unsigned or
1916signed.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1917<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1918<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]1919</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1920</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1921<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1922<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
1923</a></div>
1924<div class="doc_text">
1925<h5>Syntax:</h5>
1926<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1927</pre>
1928<h5>Overview:</h5>
1929<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
1930operands.</p>
1931<h5>Arguments:</h5>
1932<p>The two arguments to the '<tt>udiv</tt>' instruction must be
1933<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1934types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1935of the values in which case the elements must be integers.</p>
1936<h5>Semantics:</h5>
1937<p>The value produced is the unsigned integer quotient of the two operands. This
1938instruction always performs an unsigned division operation, regardless of
1939whether the arguments are unsigned or not.</p>
1940<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1941<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]1942</pre>
1943</div>
1944<!-- _______________________________________________________________________ -->
1945<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
1946</a> </div>
1947<div class="doc_text">
1948<h5>Syntax:</h5>
1949<pre> &lt;result&gt; = sdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1950</pre>
1951<h5>Overview:</h5>
1952<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
1953operands.</p>
1954<h5>Arguments:</h5>
1955<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
1956<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1957types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1958of the values in which case the elements must be integers.</p>
1959<h5>Semantics:</h5>
1960<p>The value produced is the signed integer quotient of the two operands. This
1961instruction always performs a signed division operation, regardless of whether
1962the arguments are signed or not.</p>
1963<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1964<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]1965</pre>
1966</div>
1967<!-- _______________________________________________________________________ -->
1968<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1969Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1970<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1971<h5>Syntax:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1972<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]1973</pre>
1974<h5>Overview:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1975<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1976operands.</p>
1977<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1978<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1979<a href="#t_floating">floating point</a> values. Both arguments must have
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1980identical types. This instruction can also take <a href="#t_vector">vector</a>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1981versions of floating point values.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1982<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1983<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1984<h5>Example:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1985<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]1986</pre>
1987</div>
1988<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1989<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
1990</div>
1991<div class="doc_text">
1992<h5>Syntax:</h5>
1993<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1994</pre>
1995<h5>Overview:</h5>
1996<p>The '<tt>urem</tt>' instruction returns the remainder from the
1997unsigned division of its two arguments.</p>
1998<h5>Arguments:</h5>
1999<p>The two arguments to the '<tt>urem</tt>' instruction must be
2000<a href="#t_integer">integer</a> values. Both arguments must have identical
2001types.</p>
2002<h5>Semantics:</h5>
2003<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
2004This instruction always performs an unsigned division to get the remainder,
2005regardless of whether the arguments are unsigned or not.</p>
2006<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2007<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]2008</pre>
2009
2010</div>
2011<!-- _______________________________________________________________________ -->
2012<div class="doc_subsubsection"> <a name="i_srem">'<tt>srem</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2013Instruction</a> </div>
2014<div class="doc_text">
2015<h5>Syntax:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2016<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]2017</pre>
2018<h5>Overview:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2019<p>The '<tt>srem</tt>' instruction returns the remainder from the
2020signed division of its two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2021<h5>Arguments:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2022<p>The two arguments to the '<tt>srem</tt>' instruction must be
2023<a href="#t_integer">integer</a> values. Both arguments must have identical
2024types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2025<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2026<p>This instruction returns the <i>remainder</i> of a division (where the result
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2027has the same sign as the dividend, <tt>var1</tt>), not the <i>modulo</i>
2028operator (where the result has the same sign as the divisor, <tt>var2</tt>) of
2029a value. For more information about the difference, see <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2030 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2031Math Forum</a>. For a table of how this is implemented in various languages,
Reid Spencer64f5c6c2007-03-24 22:40:44 +0000[diff] [blame]2032please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2033Wikipedia: modulo operation</a>.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2034<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2035<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]2036</pre>
2037
2038</div>
2039<!-- _______________________________________________________________________ -->
2040<div class="doc_subsubsection"> <a name="i_frem">'<tt>frem</tt>'
2041Instruction</a> </div>
2042<div class="doc_text">
2043<h5>Syntax:</h5>
2044<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2045</pre>
2046<h5>Overview:</h5>
2047<p>The '<tt>frem</tt>' instruction returns the remainder from the
2048division of its two operands.</p>
2049<h5>Arguments:</h5>
2050<p>The two arguments to the '<tt>frem</tt>' instruction must be
2051<a href="#t_floating">floating point</a> values. Both arguments must have
2052identical types.</p>
2053<h5>Semantics:</h5>
2054<p>This instruction returns the <i>remainder</i> of a division.</p>
2055<h5>Example:</h5>
2056<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]2057</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2058</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]2059
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]2060<!-- ======================================================================= -->
2061<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2062Operations</a> </div>
2063<div class="doc_text">
2064<p>Bitwise binary operators are used to do various forms of
2065bit-twiddling in a program. They are generally very efficient
2066instructions and can commonly be strength reduced from other
2067instructions. They require two operands, execute an operation on them,
2068and produce a single value. The resulting value of the bitwise binary
2069operators is always the same type as its first operand.</p>
2070</div>
2071
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2072<!-- _______________________________________________________________________ -->
2073<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2074Instruction</a> </div>
2075<div class="doc_text">
2076<h5>Syntax:</h5>
2077<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2078</pre>
2079<h5>Overview:</h5>
2080<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2081the left a specified number of bits.</p>
2082<h5>Arguments:</h5>
2083<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
2084 href="#t_integer">integer</a> type.</p>
2085<h5>Semantics:</h5>
2086<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>.</p>
2087<h5>Example:</h5><pre>
2088 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2089 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2090 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
2091</pre>
2092</div>
2093<!-- _______________________________________________________________________ -->
2094<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2095Instruction</a> </div>
2096<div class="doc_text">
2097<h5>Syntax:</h5>
2098<pre> &lt;result&gt; = lshr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2099</pre>
2100
2101<h5>Overview:</h5>
2102<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2103operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2104
2105<h5>Arguments:</h5>
2106<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
2107<a href="#t_integer">integer</a> type.</p>
2108
2109<h5>Semantics:</h5>
2110<p>This instruction always performs a logical shift right operation. The most
2111significant bits of the result will be filled with zero bits after the
2112shift.</p>
2113
2114<h5>Example:</h5>
2115<pre>
2116 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2117 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2118 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2119 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
2120</pre>
2121</div>
2122
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]2123<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2124<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2125Instruction</a> </div>
2126<div class="doc_text">
2127
2128<h5>Syntax:</h5>
2129<pre> &lt;result&gt; = ashr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2130</pre>
2131
2132<h5>Overview:</h5>
2133<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2134operand shifted to the right a specified number of bits with sign extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2135
2136<h5>Arguments:</h5>
2137<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
2138<a href="#t_integer">integer</a> type.</p>
2139
2140<h5>Semantics:</h5>
2141<p>This instruction always performs an arithmetic shift right operation,
2142The most significant bits of the result will be filled with the sign bit
2143of <tt>var1</tt>.</p>
2144
2145<h5>Example:</h5>
2146<pre>
2147 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2148 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2149 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2150 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
2151</pre>
2152</div>
2153
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2154<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2155<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2156Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2157<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2158<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2159<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]2160</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2161<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2162<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2163its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2164<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2165<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2166 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2167identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2168<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2169<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2170<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2171<div style="align: center">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2172<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2173 <tbody>
2174 <tr>
2175 <td>In0</td>
2176 <td>In1</td>
2177 <td>Out</td>
2178 </tr>
2179 <tr>
2180 <td>0</td>
2181 <td>0</td>
2182 <td>0</td>
2183 </tr>
2184 <tr>
2185 <td>0</td>
2186 <td>1</td>
2187 <td>0</td>
2188 </tr>
2189 <tr>
2190 <td>1</td>
2191 <td>0</td>
2192 <td>0</td>
2193 </tr>
2194 <tr>
2195 <td>1</td>
2196 <td>1</td>
2197 <td>1</td>
2198 </tr>
2199 </tbody>
2200</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2201</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2202<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2203<pre> &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
2204 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2205 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2206</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2207</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2208<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2209<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2210<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2211<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2212<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]2213</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2214<h5>Overview:</h5>
2215<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2216or of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2217<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2218<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2219 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2220identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2221<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2222<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2223<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2224<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2225<table border="1" cellspacing="0" cellpadding="4">
2226 <tbody>
2227 <tr>
2228 <td>In0</td>
2229 <td>In1</td>
2230 <td>Out</td>
2231 </tr>
2232 <tr>
2233 <td>0</td>
2234 <td>0</td>
2235 <td>0</td>
2236 </tr>
2237 <tr>
2238 <td>0</td>
2239 <td>1</td>
2240 <td>1</td>
2241 </tr>
2242 <tr>
2243 <td>1</td>
2244 <td>0</td>
2245 <td>1</td>
2246 </tr>
2247 <tr>
2248 <td>1</td>
2249 <td>1</td>
2250 <td>1</td>
2251 </tr>
2252 </tbody>
2253</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2254</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2255<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2256<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2257 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2258 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2259</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2260</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2261<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2262<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2263Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2264<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2265<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2266<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]2267</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2268<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2269<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2270or of its two operands. The <tt>xor</tt> is used to implement the
2271"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2272<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2273<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2274 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2275identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2276<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2277<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2278<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2279<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2280<table border="1" cellspacing="0" cellpadding="4">
2281 <tbody>
2282 <tr>
2283 <td>In0</td>
2284 <td>In1</td>
2285 <td>Out</td>
2286 </tr>
2287 <tr>
2288 <td>0</td>
2289 <td>0</td>
2290 <td>0</td>
2291 </tr>
2292 <tr>
2293 <td>0</td>
2294 <td>1</td>
2295 <td>1</td>
2296 </tr>
2297 <tr>
2298 <td>1</td>
2299 <td>0</td>
2300 <td>1</td>
2301 </tr>
2302 <tr>
2303 <td>1</td>
2304 <td>1</td>
2305 <td>0</td>
2306 </tr>
2307 </tbody>
2308</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2309</div>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2310<p> </p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2311<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2312<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2313 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2314 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2315 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2316</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2317</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2318
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2319<!-- ======================================================================= -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2320<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2321 <a name="vectorops">Vector Operations</a>
2322</div>
2323
2324<div class="doc_text">
2325
2326<p>LLVM supports several instructions to represent vector operations in a
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2327target-independent manner. These instructions cover the element-access and
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2328vector-specific operations needed to process vectors effectively. While LLVM
2329does directly support these vector operations, many sophisticated algorithms
2330will want to use target-specific intrinsics to take full advantage of a specific
2331target.</p>
2332
2333</div>
2334
2335<!-- _______________________________________________________________________ -->
2336<div class="doc_subsubsection">
2337 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2338</div>
2339
2340<div class="doc_text">
2341
2342<h5>Syntax:</h5>
2343
2344<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2345 &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]2346</pre>
2347
2348<h5>Overview:</h5>
2349
2350<p>
2351The '<tt>extractelement</tt>' instruction extracts a single scalar
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2352element from a vector at a specified index.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2353</p>
2354
2355
2356<h5>Arguments:</h5>
2357
2358<p>
2359The first operand of an '<tt>extractelement</tt>' instruction is a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2360value of <a href="#t_vector">vector</a> type. The second operand is
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2361an index indicating the position from which to extract the element.
2362The index may be a variable.</p>
2363
2364<h5>Semantics:</h5>
2365
2366<p>
2367The result is a scalar of the same type as the element type of
2368<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2369<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2370results are undefined.
2371</p>
2372
2373<h5>Example:</h5>
2374
2375<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2376 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2377</pre>
2378</div>
2379
2380
2381<!-- _______________________________________________________________________ -->
2382<div class="doc_subsubsection">
2383 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2384</div>
2385
2386<div class="doc_text">
2387
2388<h5>Syntax:</h5>
2389
2390<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2391 &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]2392</pre>
2393
2394<h5>Overview:</h5>
2395
2396<p>
2397The '<tt>insertelement</tt>' instruction inserts a scalar
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2398element into a vector at a specified index.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2399</p>
2400
2401
2402<h5>Arguments:</h5>
2403
2404<p>
2405The first operand of an '<tt>insertelement</tt>' instruction is a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2406value of <a href="#t_vector">vector</a> type. The second operand is a
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2407scalar value whose type must equal the element type of the first
2408operand. The third operand is an index indicating the position at
2409which to insert the value. The index may be a variable.</p>
2410
2411<h5>Semantics:</h5>
2412
2413<p>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2414The result is a vector of the same type as <tt>val</tt>. Its
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2415element values are those of <tt>val</tt> except at position
2416<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2417exceeds the length of <tt>val</tt>, the results are undefined.
2418</p>
2419
2420<h5>Example:</h5>
2421
2422<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2423 %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]2424</pre>
2425</div>
2426
2427<!-- _______________________________________________________________________ -->
2428<div class="doc_subsubsection">
2429 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2430</div>
2431
2432<div class="doc_text">
2433
2434<h5>Syntax:</h5>
2435
2436<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2437 &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]2438</pre>
2439
2440<h5>Overview:</h5>
2441
2442<p>
2443The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2444from two input vectors, returning a vector of the same type.
2445</p>
2446
2447<h5>Arguments:</h5>
2448
2449<p>
2450The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2451with types that match each other and types that match the result of the
2452instruction. The third argument is a shuffle mask, which has the same number
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2453of elements as the other vector type, but whose element type is always 'i32'.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2454</p>
2455
2456<p>
2457The shuffle mask operand is required to be a constant vector with either
2458constant integer or undef values.
2459</p>
2460
2461<h5>Semantics:</h5>
2462
2463<p>
2464The elements of the two input vectors are numbered from left to right across
2465both of the vectors. The shuffle mask operand specifies, for each element of
2466the result vector, which element of the two input registers the result element
2467gets. The element selector may be undef (meaning "don't care") and the second
2468operand may be undef if performing a shuffle from only one vector.
2469</p>
2470
2471<h5>Example:</h5>
2472
2473<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2474 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2475 &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]2476 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2477 &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]2478</pre>
2479</div>
2480
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]2481
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2482<!-- ======================================================================= -->
2483<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2484 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2485</div>
2486
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2487<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2488
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2489<p>A key design point of an SSA-based representation is how it
2490represents memory. In LLVM, no memory locations are in SSA form, which
2491makes things very simple. This section describes how to read, write,
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2492allocate, and free memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2493
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2494</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2495
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2496<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2497<div class="doc_subsubsection">
2498 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2499</div>
2500
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2501<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2502
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2503<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2504
2505<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2506 &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]2507</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2508
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2509<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2510
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2511<p>The '<tt>malloc</tt>' instruction allocates memory from the system
2512heap and returns a pointer to it.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2513
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2514<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2515
2516<p>The '<tt>malloc</tt>' instruction allocates
2517<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswell6e4ca612004-02-24 16:13:56 +0000[diff] [blame]2518bytes of memory from the operating system and returns a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2519appropriate type to the program. If "NumElements" is specified, it is the
2520number of elements allocated. If an alignment is specified, the value result
2521of the allocation is guaranteed to be aligned to at least that boundary. If
2522not specified, or if zero, the target can choose to align the allocation on any
2523convenient boundary.</p>
2524
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2525<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2526
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2527<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2528
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2529<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
2530a pointer is returned.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2531
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2532<h5>Example:</h5>
2533
2534<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2535 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2536
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2537 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
2538 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
2539 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
2540 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
2541 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2542</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2543</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2544
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2545<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2546<div class="doc_subsubsection">
2547 <a name="i_free">'<tt>free</tt>' Instruction</a>
2548</div>
2549
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2550<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2551
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2552<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2553
2554<pre>
2555 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2556</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2557
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2558<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2559
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2560<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2561memory heap to be reallocated in the future.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2562
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2563<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2564
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2565<p>'<tt>value</tt>' shall be a pointer value that points to a value
2566that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
2567instruction.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2568
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2569<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2570
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2571<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2572after this instruction executes.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2573
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2574<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2575
2576<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2577 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
2578 free [4 x i8]* %array
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2579</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2580</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2581
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2582<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2583<div class="doc_subsubsection">
2584 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
2585</div>
2586
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2587<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2588
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2589<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2590
2591<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2592 &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]2593</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2594
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2595<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2596
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2597<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
2598currently executing function, to be automatically released when this function
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2599returns to its caller.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2600
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2601<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2602
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2603<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2604bytes of memory on the runtime stack, returning a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2605appropriate type to the program. If "NumElements" is specified, it is the
2606number of elements allocated. If an alignment is specified, the value result
2607of the allocation is guaranteed to be aligned to at least that boundary. If
2608not specified, or if zero, the target can choose to align the allocation on any
2609convenient boundary.</p>
2610
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2611<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2612
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2613<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2614
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2615<p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2616memory is automatically released when the function returns. The '<tt>alloca</tt>'
2617instruction is commonly used to represent automatic variables that must
2618have an address available. When the function returns (either with the <tt><a
John Criswelldae2e932005-05-12 16:55:34 +0000[diff] [blame]2619 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]2620instructions), the memory is reclaimed.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2621
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2622<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2623
2624<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2625 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
2626 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
2627 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
2628 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2629</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2630</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2631
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2632<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2633<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
2634Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2635<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2636<h5>Syntax:</h5>
Christopher Lamb2330e4d2007-04-21 08:16:25 +0000[diff] [blame]2637<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]2638<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2639<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2640<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2641<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2642address from which to load. The pointer must point to a <a
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]2643 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2644marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2645the number or order of execution of this <tt>load</tt> with other
2646volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
2647instructions. </p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2648<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2649<p>The location of memory pointed to is loaded.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2650<h5>Examples:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2651<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2652 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2653 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2654 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2655</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2656</div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2657<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2658<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
2659Instruction</a> </div>
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]2660<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2661<h5>Syntax:</h5>
Christopher Lamb2330e4d2007-04-21 08:16:25 +0000[diff] [blame]2662<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
2663 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]2664</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2665<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2666<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2667<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2668<p>There are two arguments to the '<tt>store</tt>' instruction: a value
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2669to 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]2670operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2671operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2672optimizer is not allowed to modify the number or order of execution of
2673this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
2674 href="#i_store">store</a></tt> instructions.</p>
2675<h5>Semantics:</h5>
2676<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
2677at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2678<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2679<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2680 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2681 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2682 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2683</pre>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2684</div>
2685
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2686<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2687<div class="doc_subsubsection">
2688 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
2689</div>
2690
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2691<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2692<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2693<pre>
2694 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
2695</pre>
2696
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2697<h5>Overview:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2698
2699<p>
2700The '<tt>getelementptr</tt>' instruction is used to get the address of a
2701subelement of an aggregate data structure.</p>
2702
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2703<h5>Arguments:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2704
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2705<p>This instruction takes a list of integer operands that indicate what
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2706elements of the aggregate object to index to. The actual types of the arguments
2707provided depend on the type of the first pointer argument. The
2708'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2709levels 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]2710structure, only <tt>i32</tt> integer constants are allowed. When indexing
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2711into an array or pointer, only integers of 32 or 64 bits are allowed, and will
2712be sign extended to 64-bit values.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2713
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2714<p>For example, let's consider a C code fragment and how it gets
2715compiled to LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2716
2717<pre>
2718 struct RT {
2719 char A;
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2720 i32 B[10][20];
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2721 char C;
2722 };
2723 struct ST {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2724 i32 X;
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2725 double Y;
2726 struct RT Z;
2727 };
2728
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2729 define i32 *foo(struct ST *s) {
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2730 return &amp;s[1].Z.B[5][13];
2731 }
2732</pre>
2733
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2734<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2735
2736<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2737 %RT = type { i8 , [10 x [20 x i32]], i8 }
2738 %ST = type { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2739
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2740 define i32* %foo(%ST* %s) {
Brian Gaeke7283e7c2004-07-02 21:08:14 +0000[diff] [blame]2741 entry:
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2742 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
2743 ret i32* %reg
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2744 }
2745</pre>
2746
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2747<h5>Semantics:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2748
2749<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2750on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2751and <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]2752<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]2753to 64-bits. <a href="#t_struct">Structure</a> types require <tt>i32</tt>
Reid Spencer42ddd842006-12-03 16:53:48 +0000[diff] [blame]2754<b>constants</b>.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2755
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2756<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]2757type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2758}</tt>' type, a structure. The second index indexes into the third element of
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2759the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
2760i8 }</tt>' type, another structure. The third index indexes into the second
2761element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2762array. The two dimensions of the array are subscripted into, yielding an
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2763'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
2764to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2765
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2766<p>Note that it is perfectly legal to index partially through a
2767structure, returning a pointer to an inner element. Because of this,
2768the LLVM code for the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2769
2770<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2771 define i32* %foo(%ST* %s) {
2772 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2773 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
2774 %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]2775 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
2776 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
2777 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2778 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2779</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2780
2781<p>Note that it is undefined to access an array out of bounds: array and
2782pointer indexes must always be within the defined bounds of the array type.
2783The one exception for this rules is zero length arrays. These arrays are
2784defined to be accessible as variable length arrays, which requires access
2785beyond the zero'th element.</p>
2786
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2787<p>The getelementptr instruction is often confusing. For some more insight
2788into how it works, see <a href="GetElementPtr.html">the getelementptr
2789FAQ</a>.</p>
2790
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2791<h5>Example:</h5>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2792
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2793<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2794 <i>; yields [12 x i8]*:aptr</i>
2795 %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2796</pre>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2797</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2798
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2799<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]2800<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2801</div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2802<div class="doc_text">
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]2803<p>The instructions in this category are the conversion instructions (casting)
2804which all take a single operand and a type. They perform various bit conversions
2805on the operand.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2806</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2807
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2808<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2809<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2810 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
2811</div>
2812<div class="doc_text">
2813
2814<h5>Syntax:</h5>
2815<pre>
2816 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2817</pre>
2818
2819<h5>Overview:</h5>
2820<p>
2821The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
2822</p>
2823
2824<h5>Arguments:</h5>
2825<p>
2826The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
2827be 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]2828and type of the result, which must be an <a href="#t_integer">integer</a>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2829type. The bit size of <tt>value</tt> must be larger than the bit size of
2830<tt>ty2</tt>. Equal sized types are not allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2831
2832<h5>Semantics:</h5>
2833<p>
2834The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2835and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
2836larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
2837It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2838
2839<h5>Example:</h5>
2840<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2841 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2842 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
2843 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2844</pre>
2845</div>
2846
2847<!-- _______________________________________________________________________ -->
2848<div class="doc_subsubsection">
2849 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
2850</div>
2851<div class="doc_text">
2852
2853<h5>Syntax:</h5>
2854<pre>
2855 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2856</pre>
2857
2858<h5>Overview:</h5>
2859<p>The '<tt>zext</tt>' instruction zero extends its operand to type
2860<tt>ty2</tt>.</p>
2861
2862
2863<h5>Arguments:</h5>
2864<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]2865<a href="#t_integer">integer</a> type, and a type to cast it to, which must
2866also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2867<tt>value</tt> must be smaller than the bit size of the destination type,
2868<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2869
2870<h5>Semantics:</h5>
2871<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
2872bits until it reaches the size of the destination type, <tt>ty2</tt>. When the
2873the operand and the type are the same size, no bit filling is done and the
2874cast is considered a <i>no-op cast</i> because no bits change (only the type
2875changes).</p>
2876
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]2877<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]2878
2879<h5>Example:</h5>
2880<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2881 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2882 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2883</pre>
2884</div>
2885
2886<!-- _______________________________________________________________________ -->
2887<div class="doc_subsubsection">
2888 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
2889</div>
2890<div class="doc_text">
2891
2892<h5>Syntax:</h5>
2893<pre>
2894 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2895</pre>
2896
2897<h5>Overview:</h5>
2898<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
2899
2900<h5>Arguments:</h5>
2901<p>
2902The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2903<a href="#t_integer">integer</a> type, and a type to cast it to, which must
2904also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2905<tt>value</tt> must be smaller than the bit size of the destination type,
2906<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2907
2908<h5>Semantics:</h5>
2909<p>
2910The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
2911bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
2912the type <tt>ty2</tt>. When the the operand and the type are the same size,
2913no bit filling is done and the cast is considered a <i>no-op cast</i> because
2914no bits change (only the type changes).</p>
2915
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2916<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]2917
2918<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2919<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2920 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2921 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2922</pre>
2923</div>
2924
2925<!-- _______________________________________________________________________ -->
2926<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]2927 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
2928</div>
2929
2930<div class="doc_text">
2931
2932<h5>Syntax:</h5>
2933
2934<pre>
2935 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2936</pre>
2937
2938<h5>Overview:</h5>
2939<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
2940<tt>ty2</tt>.</p>
2941
2942
2943<h5>Arguments:</h5>
2944<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
2945 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
2946cast it to. The size of <tt>value</tt> must be larger than the size of
2947<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
2948<i>no-op cast</i>.</p>
2949
2950<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2951<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
2952<a href="#t_floating">floating point</a> type to a smaller
2953<a href="#t_floating">floating point</a> type. If the value cannot fit within
2954the destination type, <tt>ty2</tt>, then the results are undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]2955
2956<h5>Example:</h5>
2957<pre>
2958 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
2959 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
2960</pre>
2961</div>
2962
2963<!-- _______________________________________________________________________ -->
2964<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2965 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
2966</div>
2967<div class="doc_text">
2968
2969<h5>Syntax:</h5>
2970<pre>
2971 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2972</pre>
2973
2974<h5>Overview:</h5>
2975<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
2976floating point value.</p>
2977
2978<h5>Arguments:</h5>
2979<p>The '<tt>fpext</tt>' instruction takes a
2980<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2981and a <a href="#t_floating">floating point</a> type to cast it to. The source
2982type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2983
2984<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2985<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]2986<a href="#t_floating">floating point</a> type to a larger
2987<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2988used to make a <i>no-op cast</i> because it always changes bits. Use
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2989<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]2990
2991<h5>Example:</h5>
2992<pre>
2993 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
2994 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
2995</pre>
2996</div>
2997
2998<!-- _______________________________________________________________________ -->
2999<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]3000 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3001</div>
3002<div class="doc_text">
3003
3004<h5>Syntax:</h5>
3005<pre>
3006 &lt;result&gt; = fp2uint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3007</pre>
3008
3009<h5>Overview:</h5>
3010<p>The '<tt>fp2uint</tt>' converts a floating point <tt>value</tt> to its
3011unsigned integer equivalent of type <tt>ty2</tt>.
3012</p>
3013
3014<h5>Arguments:</h5>
3015<p>The '<tt>fp2uint</tt>' instruction takes a value to cast, which must be a
3016<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]3017must be an <a href="#t_integer">integer</a> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3018
3019<h5>Semantics:</h5>
3020<p> The '<tt>fp2uint</tt>' instruction converts its
3021<a href="#t_floating">floating point</a> operand into the nearest (rounding
3022towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3023the results are undefined.</p>
3024
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3025<p>When converting to i1, the conversion is done as a comparison against
3026zero. If the <tt>value</tt> was zero, the i1 result will be <tt>false</tt>.
3027If 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]3028
3029<h5>Example:</h5>
3030<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3031 %X = fp2uint double 123.0 to i32 <i>; yields i32:123</i>
3032 %Y = fp2uint float 1.0E+300 to i1 <i>; yields i1:true</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3033 %X = fp2uint float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3034</pre>
3035</div>
3036
3037<!-- _______________________________________________________________________ -->
3038<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3039 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3040</div>
3041<div class="doc_text">
3042
3043<h5>Syntax:</h5>
3044<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3045 &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]3046</pre>
3047
3048<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3049<p>The '<tt>fptosi</tt>' instruction converts
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3050<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]3051</p>
3052
3053
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3054<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3055<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]3056<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]3057must also be an <a href="#t_integer">integer</a> type.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3058
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3059<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3060<p>The '<tt>fptosi</tt>' instruction converts its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3061<a href="#t_floating">floating point</a> operand into the nearest (rounding
3062towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3063the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3064
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3065<p>When converting to i1, the conversion is done as a comparison against
3066zero. If the <tt>value</tt> was zero, the i1 result will be <tt>false</tt>.
3067If 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]3068
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3069<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3070<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3071 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
3072 %Y = fptosi float 1.0E-247 to i1 <i>; yields i1:true</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3073 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3074</pre>
3075</div>
3076
3077<!-- _______________________________________________________________________ -->
3078<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3079 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3080</div>
3081<div class="doc_text">
3082
3083<h5>Syntax:</h5>
3084<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3085 &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]3086</pre>
3087
3088<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3089<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3090integer and converts that value to the <tt>ty2</tt> type.</p>
3091
3092
3093<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3094<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]3095<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]3096be a <a href="#t_floating">floating point</a> type.</p>
3097
3098<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3099<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3100integer quantity and converts it to the corresponding floating point value. If
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]3101the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3102
3103
3104<h5>Example:</h5>
3105<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3106 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3107 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3108</pre>
3109</div>
3110
3111<!-- _______________________________________________________________________ -->
3112<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3113 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3114</div>
3115<div class="doc_text">
3116
3117<h5>Syntax:</h5>
3118<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3119 &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]3120</pre>
3121
3122<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3123<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3124integer and converts that value to the <tt>ty2</tt> type.</p>
3125
3126<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3127<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]3128<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]3129a <a href="#t_floating">floating point</a> type.</p>
3130
3131<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3132<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3133integer quantity and converts it to the corresponding floating point value. If
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]3134the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3135
3136<h5>Example:</h5>
3137<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3138 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3139 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3140</pre>
3141</div>
3142
3143<!-- _______________________________________________________________________ -->
3144<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3145 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3146</div>
3147<div class="doc_text">
3148
3149<h5>Syntax:</h5>
3150<pre>
3151 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3152</pre>
3153
3154<h5>Overview:</h5>
3155<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3156the integer type <tt>ty2</tt>.</p>
3157
3158<h5>Arguments:</h5>
3159<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3160must 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]3161<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
3162
3163<h5>Semantics:</h5>
3164<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3165<tt>ty2</tt> by interpreting the pointer value as an integer and either
3166truncating or zero extending that value to the size of the integer type. If
3167<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3168<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]3169are the same size, then nothing is done (<i>no-op cast</i>) other than a type
3170change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3171
3172<h5>Example:</h5>
3173<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3174 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
3175 %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]3176</pre>
3177</div>
3178
3179<!-- _______________________________________________________________________ -->
3180<div class="doc_subsubsection">
3181 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3182</div>
3183<div class="doc_text">
3184
3185<h5>Syntax:</h5>
3186<pre>
3187 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3188</pre>
3189
3190<h5>Overview:</h5>
3191<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3192a pointer type, <tt>ty2</tt>.</p>
3193
3194<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3195<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3196value to cast, and a type to cast it to, which must be a
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]3197<a href="#t_pointer">pointer</a> type.
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3198
3199<h5>Semantics:</h5>
3200<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3201<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3202the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3203size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3204the size of a pointer then a zero extension is done. If they are the same size,
3205nothing is done (<i>no-op cast</i>).</p>
3206
3207<h5>Example:</h5>
3208<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3209 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
3210 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
3211 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3212</pre>
3213</div>
3214
3215<!-- _______________________________________________________________________ -->
3216<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3217 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3218</div>
3219<div class="doc_text">
3220
3221<h5>Syntax:</h5>
3222<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3223 &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]3224</pre>
3225
3226<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3227<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3228<tt>ty2</tt> without changing any bits.</p>
3229
3230<h5>Arguments:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3231<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3232a first class value, and a type to cast it to, which must also be a <a
3233 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
Reid Spencer19b569f2007-01-09 20:08:58 +0000[diff] [blame]3234and the destination type, <tt>ty2</tt>, must be identical. If the source
3235type is a pointer, the destination type must also be a pointer.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3236
3237<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3238<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3239<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3240this conversion. The conversion is done as if the <tt>value</tt> had been
3241stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3242converted to other pointer types with this instruction. To convert pointers to
3243other types, use the <a href="#i_inttoptr">inttoptr</a> or
3244<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3245
3246<h5>Example:</h5>
3247<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3248 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3249 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
3250 %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3251</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3252</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3253
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3254<!-- ======================================================================= -->
3255<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3256<div class="doc_text">
3257<p>The instructions in this category are the "miscellaneous"
3258instructions, which defy better classification.</p>
3259</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3260
3261<!-- _______________________________________________________________________ -->
3262<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3263</div>
3264<div class="doc_text">
3265<h5>Syntax:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3266<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]3267</pre>
3268<h5>Overview:</h5>
3269<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
3270of its two integer operands.</p>
3271<h5>Arguments:</h5>
3272<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3273the condition code indicating the kind of comparison to perform. It is not
3274a value, just a keyword. The possible condition code are:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3275<ol>
3276 <li><tt>eq</tt>: equal</li>
3277 <li><tt>ne</tt>: not equal </li>
3278 <li><tt>ugt</tt>: unsigned greater than</li>
3279 <li><tt>uge</tt>: unsigned greater or equal</li>
3280 <li><tt>ult</tt>: unsigned less than</li>
3281 <li><tt>ule</tt>: unsigned less or equal</li>
3282 <li><tt>sgt</tt>: signed greater than</li>
3283 <li><tt>sge</tt>: signed greater or equal</li>
3284 <li><tt>slt</tt>: signed less than</li>
3285 <li><tt>sle</tt>: signed less or equal</li>
3286</ol>
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3287<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3288<a href="#t_pointer">pointer</a> typed. They must also be identical types.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3289<h5>Semantics:</h5>
3290<p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3291the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3292yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3293<ol>
3294 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3295 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3296 </li>
3297 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3298 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3299 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3300 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3301 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3302 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3303 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3304 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3305 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3306 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3307 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3308 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3309 <li><tt>sge</tt>: interprets the operands as signed values and yields
3310 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3311 <li><tt>slt</tt>: interprets the operands as signed values and yields
3312 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3313 <li><tt>sle</tt>: interprets the operands as signed values and yields
3314 <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]3315</ol>
3316<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3317values are compared as if they were integers.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3318
3319<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3320<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3321 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3322 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3323 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3324 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3325 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3326</pre>
3327</div>
3328
3329<!-- _______________________________________________________________________ -->
3330<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3331</div>
3332<div class="doc_text">
3333<h5>Syntax:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3334<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]3335</pre>
3336<h5>Overview:</h5>
3337<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3338of its floating point operands.</p>
3339<h5>Arguments:</h5>
3340<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3341the condition code indicating the kind of comparison to perform. It is not
3342a value, just a keyword. The possible condition code are:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3343<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3344 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3345 <li><tt>oeq</tt>: ordered and equal</li>
3346 <li><tt>ogt</tt>: ordered and greater than </li>
3347 <li><tt>oge</tt>: ordered and greater than or equal</li>
3348 <li><tt>olt</tt>: ordered and less than </li>
3349 <li><tt>ole</tt>: ordered and less than or equal</li>
3350 <li><tt>one</tt>: ordered and not equal</li>
3351 <li><tt>ord</tt>: ordered (no nans)</li>
3352 <li><tt>ueq</tt>: unordered or equal</li>
3353 <li><tt>ugt</tt>: unordered or greater than </li>
3354 <li><tt>uge</tt>: unordered or greater than or equal</li>
3355 <li><tt>ult</tt>: unordered or less than </li>
3356 <li><tt>ule</tt>: unordered or less than or equal</li>
3357 <li><tt>une</tt>: unordered or not equal</li>
3358 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3359 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3360</ol>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3361<p><i>Ordered</i> means that neither operand is a QNAN while
Reid Spencer93a49852006-12-06 07:08:07 +0000[diff] [blame]3362<i>unordered</i> means that either operand may be a QNAN.</p>
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3363<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be
3364<a href="#t_floating">floating point</a> typed. They must have identical
3365types.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3366<h5>Semantics:</h5>
3367<p>The '<tt>fcmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3368the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3369yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3370<ol>
3371 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3372 <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]3373 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3374 <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]3375 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3376 <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]3377 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3378 <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]3379 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3380 <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]3381 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3382 <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]3383 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3384 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3385 <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]3386 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3387 <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]3388 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3389 <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]3390 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3391 <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]3392 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3393 <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]3394 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3395 <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]3396 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3397 <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]3398 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3399</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3400
3401<h5>Example:</h5>
3402<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3403 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3404 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3405 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3406</pre>
3407</div>
3408
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3409<!-- _______________________________________________________________________ -->
3410<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
3411Instruction</a> </div>
3412<div class="doc_text">
3413<h5>Syntax:</h5>
3414<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
3415<h5>Overview:</h5>
3416<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
3417the SSA graph representing the function.</p>
3418<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3419<p>The type of the incoming values is specified with the first type
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3420field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
3421as arguments, with one pair for each predecessor basic block of the
3422current block. Only values of <a href="#t_firstclass">first class</a>
3423type may be used as the value arguments to the PHI node. Only labels
3424may be used as the label arguments.</p>
3425<p>There must be no non-phi instructions between the start of a basic
3426block and the PHI instructions: i.e. PHI instructions must be first in
3427a basic block.</p>
3428<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3429<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
3430specified by the pair corresponding to the predecessor basic block that executed
3431just prior to the current block.</p>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3432<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3433<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]3434</div>
3435
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3436<!-- _______________________________________________________________________ -->
3437<div class="doc_subsubsection">
3438 <a name="i_select">'<tt>select</tt>' Instruction</a>
3439</div>
3440
3441<div class="doc_text">
3442
3443<h5>Syntax:</h5>
3444
3445<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3446 &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]3447</pre>
3448
3449<h5>Overview:</h5>
3450
3451<p>
3452The '<tt>select</tt>' instruction is used to choose one value based on a
3453condition, without branching.
3454</p>
3455
3456
3457<h5>Arguments:</h5>
3458
3459<p>
3460The '<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.
3461</p>
3462
3463<h5>Semantics:</h5>
3464
3465<p>
3466If the boolean condition evaluates to true, the instruction returns the first
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3467value argument; otherwise, it returns the second value argument.
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3468</p>
3469
3470<h5>Example:</h5>
3471
3472<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3473 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3474</pre>
3475</div>
3476
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]3477
3478<!-- _______________________________________________________________________ -->
3479<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3480 <a name="i_call">'<tt>call</tt>' Instruction</a>
3481</div>
3482
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3483<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3484
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3485<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3486<pre>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3487 &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]3488</pre>
3489
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3490<h5>Overview:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3491
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3492<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3493
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3494<h5>Arguments:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3495
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3496<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3497
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3498<ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3499 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3500 <p>The optional "tail" marker indicates whether the callee function accesses
3501 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3502 function call is eligible for tail call optimization. Note that calls may
3503 be marked "tail" even if they do not occur before a <a
3504 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3505 </li>
3506 <li>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3507 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3508 convention</a> the call should use. If none is specified, the call defaults
3509 to using C calling conventions.
3510 </li>
3511 <li>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3512 <p>'<tt>ty</tt>': shall be the signature of the pointer to function value
3513 being invoked. The argument types must match the types implied by this
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3514 signature. This type can be omitted if the function is not varargs and
3515 if the function type does not return a pointer to a function.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3516 </li>
3517 <li>
3518 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
3519 be invoked. In most cases, this is a direct function invocation, but
3520 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3521 to function value.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3522 </li>
3523 <li>
3524 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencera7e302a2005-05-01 22:22:57 +0000[diff] [blame]3525 function signature argument types. All arguments must be of
3526 <a href="#t_firstclass">first class</a> type. If the function signature
3527 indicates the function accepts a variable number of arguments, the extra
3528 arguments can be specified.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3529 </li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3530</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3531
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3532<h5>Semantics:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3533
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3534<p>The '<tt>call</tt>' instruction is used to cause control flow to
3535transfer to a specified function, with its incoming arguments bound to
3536the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
3537instruction in the called function, control flow continues with the
3538instruction after the function call, and the return value of the
3539function is bound to the result argument. This is a simpler case of
3540the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3541
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3542<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3543
3544<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3545 %retval = call i32 %test(i32 %argc)
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3546 call i32(i8 *, ...) *%printf(i8 * %msg, i32 12, i8 42);
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3547 %X = tail call i32 %foo()
3548 %Y = tail call <a href="#callingconv">fastcc</a> i32 %foo()
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3549</pre>
3550
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3551</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3552
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3553<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3554<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3555 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3556</div>
3557
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3558<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3559
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3560<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3561
3562<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3563 &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]3564</pre>
3565
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3566<h5>Overview:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3567
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3568<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3569the "variable argument" area of a function call. It is used to implement the
3570<tt>va_arg</tt> macro in C.</p>
3571
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3572<h5>Arguments:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3573
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3574<p>This instruction takes a <tt>va_list*</tt> value and the type of
3575the argument. It returns a value of the specified argument type and
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3576increments the <tt>va_list</tt> to point to the next argument. The
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3577actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3578
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3579<h5>Semantics:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3580
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3581<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
3582type from the specified <tt>va_list</tt> and causes the
3583<tt>va_list</tt> to point to the next argument. For more information,
3584see the variable argument handling <a href="#int_varargs">Intrinsic
3585Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3586
3587<p>It is legal for this instruction to be called in a function which does not
3588take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3589function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3590
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3591<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3592href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3593argument.</p>
3594
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3595<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3596
3597<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
3598
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3599</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3600
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3601<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3602<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
3603<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3604
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3605<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3606
3607<p>LLVM supports the notion of an "intrinsic function". These functions have
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]3608well known names and semantics and are required to follow certain restrictions.
3609Overall, these intrinsics represent an extension mechanism for the LLVM
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3610language that does not require changing all of the transformations in LLVM when
3611adding to the language (or the bytecode reader/writer, the parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3612
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3613<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3614prefix is reserved in LLVM for intrinsic names; thus, function names may not
3615begin with this prefix. Intrinsic functions must always be external functions:
3616you cannot define the body of intrinsic functions. Intrinsic functions may
3617only be used in call or invoke instructions: it is illegal to take the address
3618of an intrinsic function. Additionally, because intrinsic functions are part
3619of the LLVM language, it is required if any are added that they be documented
3620here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3621
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3622<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]3623a family of functions that perform the same operation but on different data
3624types. This is most frequent with the integer types. Since LLVM can represent
3625over 8 million different integer types, there is a way to declare an intrinsic
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3626that can be overloaded based on its arguments. Such an intrinsic will have the
3627names of its argument types encoded into its function name, each
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]3628preceded by a period. For example, the <tt>llvm.ctpop</tt> function can take an
3629integer of any width. This leads to a family of functions such as
3630<tt>i32 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i32 @llvm.ctpop.i29(i29 %val)</tt>.
3631</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3632
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]3633
3634<p>To learn how to add an intrinsic function, please see the
3635<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3636</p>
3637
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3638</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3639
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3640<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3641<div class="doc_subsection">
3642 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
3643</div>
3644
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3645<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3646
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3647<p>Variable argument support is defined in LLVM with the <a
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3648 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3649intrinsic functions. These functions are related to the similarly
3650named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3651
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3652<p>All of these functions operate on arguments that use a
3653target-specific value type "<tt>va_list</tt>". The LLVM assembly
3654language reference manual does not define what this type is, so all
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3655transformations should be prepared to handle these functions regardless of
3656the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3657
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]3658<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]3659instruction and the variable argument handling intrinsic functions are
3660used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3661
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3662<pre>
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3663define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3664 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3665 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3666 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3667 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3668
3669 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3670 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3671
3672 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3673 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3674 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3675 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3676 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3677
3678 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3679 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3680 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3681}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3682
3683declare void @llvm.va_start(i8*)
3684declare void @llvm.va_copy(i8*, i8*)
3685declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3686</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3687</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3688
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3689<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3690<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3691 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3692</div>
3693
3694
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3695<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3696<h5>Syntax:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3697<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3698<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3699<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
3700<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
3701href="#i_va_arg">va_arg</a></tt>.</p>
3702
3703<h5>Arguments:</h5>
3704
3705<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
3706
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3707<h5>Semantics:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3708
3709<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
3710macro available in C. In a target-dependent way, it initializes the
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3711<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]3712<tt>va_arg</tt> will produce the first variable argument passed to the function.
3713Unlike 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]3714last argument of the function as the compiler can figure that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3715
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3716</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3717
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3718<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3719<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3720 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3721</div>
3722
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3723<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3724<h5>Syntax:</h5>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3725<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3726<h5>Overview:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3727
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3728<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3729which 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]3730or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3731
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3732<h5>Arguments:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3733
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3734<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]3735
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3736<h5>Semantics:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3737
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3738<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]3739macro available in C. In a target-dependent way, it destroys the
3740<tt>va_list</tt> element to which the argument points. Calls to <a
3741href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
3742<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
3743<tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3744
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3745</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3746
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3747<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3748<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3749 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3750</div>
3751
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3752<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3753
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3754<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3755
3756<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3757 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3758</pre>
3759
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3760<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3761
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3762<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
3763from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3764
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3765<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3766
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3767<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]3768The 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]3769
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3770
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3771<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3772
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3773<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
3774macro available in C. In a target-dependent way, it copies the source
3775<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
3776intrinsic is necessary because the <tt><a href="#int_va_start">
3777llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
3778example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3779
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3780</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3781
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3782<!-- ======================================================================= -->
3783<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3784 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
3785</div>
3786
3787<div class="doc_text">
3788
3789<p>
3790LLVM support for <a href="GarbageCollection.html">Accurate Garbage
3791Collection</a> requires the implementation and generation of these intrinsics.
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3792These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3793stack</a>, as well as garbage collector implementations that require <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3794href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3795Front-ends for type-safe garbage collected languages should generate these
3796intrinsics to make use of the LLVM garbage collectors. For more details, see <a
3797href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
3798</p>
3799</div>
3800
3801<!-- _______________________________________________________________________ -->
3802<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3803 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3804</div>
3805
3806<div class="doc_text">
3807
3808<h5>Syntax:</h5>
3809
3810<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3811 declare void @llvm.gcroot(&lt;ty&gt;** %ptrloc, &lt;ty2&gt;* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3812</pre>
3813
3814<h5>Overview:</h5>
3815
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]3816<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]3817the code generator, and allows some metadata to be associated with it.</p>
3818
3819<h5>Arguments:</h5>
3820
3821<p>The first argument specifies the address of a stack object that contains the
3822root pointer. The second pointer (which must be either a constant or a global
3823value address) contains the meta-data to be associated with the root.</p>
3824
3825<h5>Semantics:</h5>
3826
3827<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
3828location. At compile-time, the code generator generates information to allow
3829the runtime to find the pointer at GC safe points.
3830</p>
3831
3832</div>
3833
3834
3835<!-- _______________________________________________________________________ -->
3836<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3837 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3838</div>
3839
3840<div class="doc_text">
3841
3842<h5>Syntax:</h5>
3843
3844<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3845 declare i8 * @llvm.gcread(i8 * %ObjPtr, i8 ** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3846</pre>
3847
3848<h5>Overview:</h5>
3849
3850<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
3851locations, allowing garbage collector implementations that require read
3852barriers.</p>
3853
3854<h5>Arguments:</h5>
3855
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3856<p>The second argument is the address to read from, which should be an address
3857allocated from the garbage collector. The first object is a pointer to the
3858start of the referenced object, if needed by the language runtime (otherwise
3859null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3860
3861<h5>Semantics:</h5>
3862
3863<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
3864instruction, but may be replaced with substantially more complex code by the
3865garbage collector runtime, as needed.</p>
3866
3867</div>
3868
3869
3870<!-- _______________________________________________________________________ -->
3871<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3872 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3873</div>
3874
3875<div class="doc_text">
3876
3877<h5>Syntax:</h5>
3878
3879<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3880 declare void @llvm.gcwrite(i8 * %P1, i8 * %Obj, i8 ** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3881</pre>
3882
3883<h5>Overview:</h5>
3884
3885<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
3886locations, allowing garbage collector implementations that require write
3887barriers (such as generational or reference counting collectors).</p>
3888
3889<h5>Arguments:</h5>
3890
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3891<p>The first argument is the reference to store, the second is the start of the
3892object to store it to, and the third is the address of the field of Obj to
3893store to. If the runtime does not require a pointer to the object, Obj may be
3894null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3895
3896<h5>Semantics:</h5>
3897
3898<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
3899instruction, but may be replaced with substantially more complex code by the
3900garbage collector runtime, as needed.</p>
3901
3902</div>
3903
3904
3905
3906<!-- ======================================================================= -->
3907<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3908 <a name="int_codegen">Code Generator Intrinsics</a>
3909</div>
3910
3911<div class="doc_text">
3912<p>
3913These intrinsics are provided by LLVM to expose special features that may only
3914be implemented with code generator support.
3915</p>
3916
3917</div>
3918
3919<!-- _______________________________________________________________________ -->
3920<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3921 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3922</div>
3923
3924<div class="doc_text">
3925
3926<h5>Syntax:</h5>
3927<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3928 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3929</pre>
3930
3931<h5>Overview:</h5>
3932
3933<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]3934The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
3935target-specific value indicating the return address of the current function
3936or one of its callers.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3937</p>
3938
3939<h5>Arguments:</h5>
3940
3941<p>
3942The argument to this intrinsic indicates which function to return the address
3943for. Zero indicates the calling function, one indicates its caller, etc. The
3944argument is <b>required</b> to be a constant integer value.
3945</p>
3946
3947<h5>Semantics:</h5>
3948
3949<p>
3950The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
3951the return address of the specified call frame, or zero if it cannot be
3952identified. The value returned by this intrinsic is likely to be incorrect or 0
3953for arguments other than zero, so it should only be used for debugging purposes.
3954</p>
3955
3956<p>
3957Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]3958aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3959source-language caller.
3960</p>
3961</div>
3962
3963
3964<!-- _______________________________________________________________________ -->
3965<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3966 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3967</div>
3968
3969<div class="doc_text">
3970
3971<h5>Syntax:</h5>
3972<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3973 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3974</pre>
3975
3976<h5>Overview:</h5>
3977
3978<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]3979The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
3980target-specific frame pointer value for the specified stack frame.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3981</p>
3982
3983<h5>Arguments:</h5>
3984
3985<p>
3986The argument to this intrinsic indicates which function to return the frame
3987pointer for. Zero indicates the calling function, one indicates its caller,
3988etc. The argument is <b>required</b> to be a constant integer value.
3989</p>
3990
3991<h5>Semantics:</h5>
3992
3993<p>
3994The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
3995the frame address of the specified call frame, or zero if it cannot be
3996identified. The value returned by this intrinsic is likely to be incorrect or 0
3997for arguments other than zero, so it should only be used for debugging purposes.
3998</p>
3999
4000<p>
4001Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]4002aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4003source-language caller.
4004</p>
4005</div>
4006
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4007<!-- _______________________________________________________________________ -->
4008<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4009 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4010</div>
4011
4012<div class="doc_text">
4013
4014<h5>Syntax:</h5>
4015<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4016 declare i8 *@llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4017</pre>
4018
4019<h5>Overview:</h5>
4020
4021<p>
4022The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4023the function stack, for use with <a href="#int_stackrestore">
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4024<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
4025features like scoped automatic variable sized arrays in C99.
4026</p>
4027
4028<h5>Semantics:</h5>
4029
4030<p>
4031This intrinsic returns a opaque pointer value that can be passed to <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4032href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4033<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
4034<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
4035state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
4036practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
4037that were allocated after the <tt>llvm.stacksave</tt> was executed.
4038</p>
4039
4040</div>
4041
4042<!-- _______________________________________________________________________ -->
4043<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4044 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4045</div>
4046
4047<div class="doc_text">
4048
4049<h5>Syntax:</h5>
4050<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4051 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4052</pre>
4053
4054<h5>Overview:</h5>
4055
4056<p>
4057The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
4058the function stack to the state it was in when the corresponding <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4059href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4060useful for implementing language features like scoped automatic variable sized
4061arrays in C99.
4062</p>
4063
4064<h5>Semantics:</h5>
4065
4066<p>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4067See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4068</p>
4069
4070</div>
4071
4072
4073<!-- _______________________________________________________________________ -->
4074<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4075 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4076</div>
4077
4078<div class="doc_text">
4079
4080<h5>Syntax:</h5>
4081<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4082 declare void @llvm.prefetch(i8 * &lt;address&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4083 i32 &lt;rw&gt;, i32 &lt;locality&gt;)
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4084</pre>
4085
4086<h5>Overview:</h5>
4087
4088
4089<p>
4090The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4091a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
4092no
4093effect on the behavior of the program but can change its performance
Chris Lattner2a615362005-02-28 19:47:14 +0000[diff] [blame]4094characteristics.
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4095</p>
4096
4097<h5>Arguments:</h5>
4098
4099<p>
4100<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
4101determining if the fetch should be for a read (0) or write (1), and
4102<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattneraeffb4a2005-03-07 20:31:38 +0000[diff] [blame]4103locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4104<tt>locality</tt> arguments must be constant integers.
4105</p>
4106
4107<h5>Semantics:</h5>
4108
4109<p>
4110This intrinsic does not modify the behavior of the program. In particular,
4111prefetches cannot trap and do not produce a value. On targets that support this
4112intrinsic, the prefetch can provide hints to the processor cache for better
4113performance.
4114</p>
4115
4116</div>
4117
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4118<!-- _______________________________________________________________________ -->
4119<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4120 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4121</div>
4122
4123<div class="doc_text">
4124
4125<h5>Syntax:</h5>
4126<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4127 declare void @llvm.pcmarker( i32 &lt;id&gt; )
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4128</pre>
4129
4130<h5>Overview:</h5>
4131
4132
4133<p>
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4134The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
4135(PC) in a region of
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4136code to simulators and other tools. The method is target specific, but it is
4137expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]4138The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnerd07c3f42005-11-15 06:07:55 +0000[diff] [blame]4139after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb3e7afd2006-03-24 07:16:10 +0000[diff] [blame]4140optimizations. The intended use is to be inserted after optimizations to allow
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4141correlations of simulation runs.
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4142</p>
4143
4144<h5>Arguments:</h5>
4145
4146<p>
4147<tt>id</tt> is a numerical id identifying the marker.
4148</p>
4149
4150<h5>Semantics:</h5>
4151
4152<p>
4153This intrinsic does not modify the behavior of the program. Backends that do not
4154support this intrinisic may ignore it.
4155</p>
4156
4157</div>
4158
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4159<!-- _______________________________________________________________________ -->
4160<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4161 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4162</div>
4163
4164<div class="doc_text">
4165
4166<h5>Syntax:</h5>
4167<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4168 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4169</pre>
4170
4171<h5>Overview:</h5>
4172
4173
4174<p>
4175The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
4176counter register (or similar low latency, high accuracy clocks) on those targets
4177that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
4178As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
4179should only be used for small timings.
4180</p>
4181
4182<h5>Semantics:</h5>
4183
4184<p>
4185When directly supported, reading the cycle counter should not modify any memory.
4186Implementations are allowed to either return a application specific value or a
4187system wide value. On backends without support, this is lowered to a constant 0.
4188</p>
4189
4190</div>
4191
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4192<!-- ======================================================================= -->
4193<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4194 <a name="int_libc">Standard C Library Intrinsics</a>
4195</div>
4196
4197<div class="doc_text">
4198<p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4199LLVM provides intrinsics for a few important standard C library functions.
4200These intrinsics allow source-language front-ends to pass information about the
4201alignment of the pointer arguments to the code generator, providing opportunity
4202for more efficient code generation.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4203</p>
4204
4205</div>
4206
4207<!-- _______________________________________________________________________ -->
4208<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4209 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4210</div>
4211
4212<div class="doc_text">
4213
4214<h5>Syntax:</h5>
4215<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4216 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4217 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4218 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4219 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4220</pre>
4221
4222<h5>Overview:</h5>
4223
4224<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4225The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4226location to the destination location.
4227</p>
4228
4229<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4230Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4231intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4232</p>
4233
4234<h5>Arguments:</h5>
4235
4236<p>
4237The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4238the source. The third argument is an integer argument
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4239specifying the number of bytes to copy, and the fourth argument is the alignment
4240of the source and destination locations.
4241</p>
4242
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4243<p>
4244If 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]4245the caller guarantees that both the source and destination pointers are aligned
4246to that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4247</p>
4248
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4249<h5>Semantics:</h5>
4250
4251<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4252The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4253location to the destination location, which are not allowed to overlap. It
4254copies "len" bytes of memory over. If the argument is known to be aligned to
4255some boundary, this can be specified as the fourth argument, otherwise it should
4256be set to 0 or 1.
4257</p>
4258</div>
4259
4260
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4261<!-- _______________________________________________________________________ -->
4262<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4263 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4264</div>
4265
4266<div class="doc_text">
4267
4268<h5>Syntax:</h5>
4269<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4270 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4271 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4272 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4273 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4274</pre>
4275
4276<h5>Overview:</h5>
4277
4278<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4279The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
4280location to the destination location. It is similar to the
4281'<tt>llvm.memcmp</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4282</p>
4283
4284<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4285Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
4286intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4287</p>
4288
4289<h5>Arguments:</h5>
4290
4291<p>
4292The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4293the source. The third argument is an integer argument
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4294specifying the number of bytes to copy, and the fourth argument is the alignment
4295of the source and destination locations.
4296</p>
4297
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4298<p>
4299If 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]4300the caller guarantees that the source and destination pointers are aligned to
4301that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4302</p>
4303
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4304<h5>Semantics:</h5>
4305
4306<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4307The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4308location to the destination location, which may overlap. It
4309copies "len" bytes of memory over. If the argument is known to be aligned to
4310some boundary, this can be specified as the fourth argument, otherwise it should
4311be set to 0 or 1.
4312</p>
4313</div>
4314
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4315
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4316<!-- _______________________________________________________________________ -->
4317<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4318 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4319</div>
4320
4321<div class="doc_text">
4322
4323<h5>Syntax:</h5>
4324<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4325 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4326 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4327 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4328 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4329</pre>
4330
4331<h5>Overview:</h5>
4332
4333<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4334The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4335byte value.
4336</p>
4337
4338<p>
4339Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
4340does not return a value, and takes an extra alignment argument.
4341</p>
4342
4343<h5>Arguments:</h5>
4344
4345<p>
4346The first argument is a pointer to the destination to fill, the second is the
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4347byte value to fill it with, the third argument is an integer
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4348argument specifying the number of bytes to fill, and the fourth argument is the
4349known alignment of destination location.
4350</p>
4351
4352<p>
4353If 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]4354the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4355</p>
4356
4357<h5>Semantics:</h5>
4358
4359<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4360The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
4361the
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4362destination location. If the argument is known to be aligned to some boundary,
4363this can be specified as the fourth argument, otherwise it should be set to 0 or
43641.
4365</p>
4366</div>
4367
4368
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4369<!-- _______________________________________________________________________ -->
4370<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4371 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4372</div>
4373
4374<div class="doc_text">
4375
4376<h5>Syntax:</h5>
4377<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4378 declare float @llvm.sqrt.f32(float %Val)
4379 declare double @llvm.sqrt.f64(double %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4380</pre>
4381
4382<h5>Overview:</h5>
4383
4384<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4385The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4386returning the same value as the libm '<tt>sqrt</tt>' function would. Unlike
4387<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
4388negative numbers (which allows for better optimization).
4389</p>
4390
4391<h5>Arguments:</h5>
4392
4393<p>
4394The argument and return value are floating point numbers of the same type.
4395</p>
4396
4397<h5>Semantics:</h5>
4398
4399<p>
4400This function returns the sqrt of the specified operand if it is a positive
4401floating point number.
4402</p>
4403</div>
4404
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4405<!-- _______________________________________________________________________ -->
4406<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4407 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4408</div>
4409
4410<div class="doc_text">
4411
4412<h5>Syntax:</h5>
4413<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4414 declare float @llvm.powi.f32(float %Val, i32 %power)
4415 declare double @llvm.powi.f64(double %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4416</pre>
4417
4418<h5>Overview:</h5>
4419
4420<p>
4421The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
4422specified (positive or negative) power. The order of evaluation of
4423multiplications is not defined.
4424</p>
4425
4426<h5>Arguments:</h5>
4427
4428<p>
4429The second argument is an integer power, and the first is a value to raise to
4430that power.
4431</p>
4432
4433<h5>Semantics:</h5>
4434
4435<p>
4436This function returns the first value raised to the second power with an
4437unspecified sequence of rounding operations.</p>
4438</div>
4439
4440
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4441<!-- ======================================================================= -->
4442<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4443 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4444</div>
4445
4446<div class="doc_text">
4447<p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4448LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4449These allow efficient code generation for some algorithms.
4450</p>
4451
4452</div>
4453
4454<!-- _______________________________________________________________________ -->
4455<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4456 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4457</div>
4458
4459<div class="doc_text">
4460
4461<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4462<p>This is an overloaded intrinsic function. You can use bswap on any integer
4463type that is an even number of bytes (i.e. BitWidth % 16 == 0). Note the suffix
4464that includes the type for the result and the operand.
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4465<pre>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4466 declare i16 @llvm.bswap.i16.i16(i16 &lt;id&gt;)
4467 declare i32 @llvm.bswap.i32.i32(i32 &lt;id&gt;)
Reid Spencer543ab1d2007-04-02 00:19:52 +0000[diff] [blame]4468 declare i64 @llvm.bswap.i64.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4469</pre>
4470
4471<h5>Overview:</h5>
4472
4473<p>
Reid Spencer338ea092007-04-02 02:25:19 +0000[diff] [blame]4474The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4475values with an even number of bytes (positive multiple of 16 bits). These are
4476useful for performing operations on data that is not in the target's native
4477byte order.
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4478</p>
4479
4480<h5>Semantics:</h5>
4481
4482<p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4483The <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]4484and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
4485intrinsic returns an i32 value that has the four bytes of the input i32
4486swapped, 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]4487i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48.i48</tt>,
4488<tt>llvm.bswap.i64.i64</tt> and other intrinsics extend this concept to
4489additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4490</p>
4491
4492</div>
4493
4494<!-- _______________________________________________________________________ -->
4495<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4496 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4497</div>
4498
4499<div class="doc_text">
4500
4501<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4502<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
4503width. Not all targets support all bit widths however.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4504<pre>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4505 declare i32 @llvm.ctpop.i8 (i8 &lt;src&gt;)
4506 declare i32 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4507 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4508 declare i32 @llvm.ctpop.i64(i64 &lt;src&gt;)
4509 declare i32 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4510</pre>
4511
4512<h5>Overview:</h5>
4513
4514<p>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4515The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
4516value.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4517</p>
4518
4519<h5>Arguments:</h5>
4520
4521<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]4522The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4523integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4524</p>
4525
4526<h5>Semantics:</h5>
4527
4528<p>
4529The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
4530</p>
4531</div>
4532
4533<!-- _______________________________________________________________________ -->
4534<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]4535 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4536</div>
4537
4538<div class="doc_text">
4539
4540<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4541<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
4542integer bit width. Not all targets support all bit widths however.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4543<pre>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4544 declare i32 @llvm.ctlz.i8 (i8 &lt;src&gt;)
4545 declare i32 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4546 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4547 declare i32 @llvm.ctlz.i64(i64 &lt;src&gt;)
4548 declare i32 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4549</pre>
4550
4551<h5>Overview:</h5>
4552
4553<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4554The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
4555leading zeros in a variable.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4556</p>
4557
4558<h5>Arguments:</h5>
4559
4560<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]4561The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4562integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4563</p>
4564
4565<h5>Semantics:</h5>
4566
4567<p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4568The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
4569in 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]4570of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4571</p>
4572</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4573
4574
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4575
4576<!-- _______________________________________________________________________ -->
4577<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]4578 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4579</div>
4580
4581<div class="doc_text">
4582
4583<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4584<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
4585integer bit width. Not all targets support all bit widths however.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4586<pre>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4587 declare i32 @llvm.cttz.i8 (i8 &lt;src&gt;)
4588 declare i32 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4589 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4590 declare i32 @llvm.cttz.i64(i64 &lt;src&gt;)
4591 declare i32 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4592</pre>
4593
4594<h5>Overview:</h5>
4595
4596<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4597The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
4598trailing zeros.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4599</p>
4600
4601<h5>Arguments:</h5>
4602
4603<p>
4604The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4605integer type. The return type must match the argument type.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4606</p>
4607
4608<h5>Semantics:</h5>
4609
4610<p>
4611The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
4612in a variable. If the src == 0 then the result is the size in bits of the type
4613of src. For example, <tt>llvm.cttz(2) = 1</tt>.
4614</p>
4615</div>
4616
Reid Spencer497d93e2007-04-01 08:27:01 +0000[diff] [blame]4617<!-- _______________________________________________________________________ -->
4618<div class="doc_subsubsection">
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]4619 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4620</div>
4621
4622<div class="doc_text">
4623
4624<h5>Syntax:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]4625<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4626on any integer bit width.
4627<pre>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]4628 declare i17 @llvm.part.select.i17.i17 (i17 %val, i32 %loBit, i32 %hiBit)
4629 declare i29 @llvm.part.select.i29.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4630</pre>
4631
4632<h5>Overview:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]4633<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4634range of bits from an integer value and returns them in the same bit width as
4635the original value.</p>
4636
4637<h5>Arguments:</h5>
4638<p>The first argument, <tt>%val</tt> and the result may be integer types of
4639any bit width but they must have the same bit width. The second and third
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4640arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4641
4642<h5>Semantics:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]4643<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4644of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
4645<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
4646operates in forward mode.</p>
4647<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
4648right by <tt>%loBit</tt> bits and then ANDing it with a mask with
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4649only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
4650<ol>
4651 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
4652 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
4653 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
4654 to determine the number of bits to retain.</li>
4655 <li>A mask of the retained bits is created by shifting a -1 value.</li>
4656 <li>The mask is ANDed with <tt>%val</tt> to produce the result.
4657</ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4658<p>In reverse mode, a similar computation is made except that:</p>
4659<ol>
4660 <li>The bits selected wrap around to include both the highest and lowest bits.
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]4661 For example, part.select(i16 X, 4, 7) selects bits from X with a mask of
4662 0x00F0 (forwards case) while part.select(i16 X, 8, 3) selects bits from X
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4663 with a mask of 0xFF0F.</li>
4664 <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]4665 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]4666 0x0A6F.</li>
4667</ol>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4668</div>
4669
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]4670<div class="doc_subsubsection">
4671 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
4672</div>
4673
4674<div class="doc_text">
4675
4676<h5>Syntax:</h5>
4677<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
4678on any integer bit width.
4679<pre>
4680 declare i17 @llvm.part.set.i17.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
4681 declare i29 @llvm.part.set.i29.i29.i9 (i29 %val, i9 %repl, i32 %lo, i32 %hi)
4682</pre>
4683
4684<h5>Overview:</h5>
4685<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
4686of bits in an integer value with another integer value. It returns the integer
4687with the replaced bits.</p>
4688
4689<h5>Arguments:</h5>
4690<p>The first argument, <tt>%val</tt> and the result may be integer types of
4691any bit width but they must have the same bit width. <tt>%val</tt> is the value
4692whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
4693integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
4694type since they specify only a bit index.</p>
4695
4696<h5>Semantics:</h5>
4697<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
4698of operation: forwards and reverse. If <tt>%lo</tt> is greater than
4699<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
4700operates in forward mode.</p>
4701<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
4702truncating it down to the size of the replacement area or zero extending it
4703up to that size.</p>
4704<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
4705are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
4706in <tt>%repl</tt> replaces the <tt>%lo</tt>th bit in <tt>%val</tt> and etc. up
4707to the <tt>%hi</tt>th bit.
4708<p>In reverse mode, a similar computation is made except that the bits replaced
4709wrap around to include both the highest and lowest bits. For example, if a
471016 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]4711cause these bits to be set: <tt>0xFF1F</tt>.</p>
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]4712<h5>Examples:</h5>
4713<pre>
Reid Spencerf0dbf642007-04-12 01:03:03 +0000[diff] [blame]4714 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
4715 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0x0060
4716 llvm.part.set(0xFFFF, 0, 8, 3) -&gt; 0x00F0
4717 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]4718</pre>
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]4719</div>
4720
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4721<!-- ======================================================================= -->
4722<div class="doc_subsection">
4723 <a name="int_debugger">Debugger Intrinsics</a>
4724</div>
4725
4726<div class="doc_text">
4727<p>
4728The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
4729are described in the <a
4730href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
4731Debugging</a> document.
4732</p>
4733</div>
4734
4735
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]4736<!-- ======================================================================= -->
4737<div class="doc_subsection">
4738 <a name="int_eh">Exception Handling Intrinsics</a>
4739</div>
4740
4741<div class="doc_text">
4742<p> The LLVM exception handling intrinsics (which all start with
4743<tt>llvm.eh.</tt> prefix), are described in the <a
4744href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
4745Handling</a> document. </p>
4746</div>
4747
4748
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4749<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4750<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]4751<address>
4752 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
4753 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
4754 <a href="http://validator.w3.org/check/referer"><img
4755 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!" /></a>
4756
4757 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]4758 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]4759 Last modified: $Date$
4760</address>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4761</body>
4762</html>