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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 9445e9aaa0240a897baf464ff89255acdcc7fbc9 / . / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
Reid Spencer3921c742004-08-26 20:44:00 +0000[diff] [blame]6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
8 <meta name="description"
9 content="LLVM Assembly Language Reference Manual.">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]14
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]15<div class="doc_title"> LLVM Language Reference Manual </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a></li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]24 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]25 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]26 <li><a href="#functionstructure">Functions</a></li>
Anton 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>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]194 <li><a href="#int_general">General intrinsics</a></li>
195 <ol>
196 <li><a href="#int_var_annotation">'<tt>llvm.var.annotation</tt>'
197 Intrinsic</a></li>
198 </ol>
199 </li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]200 </ol>
201 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]202</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]203
204<div class="doc_author">
205 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
206 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]207</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]208
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]209<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]210<div class="doc_section"> <a name="abstract">Abstract </a></div>
211<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]212
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]213<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]214<p>This document is a reference manual for the LLVM assembly language.
215LLVM is an SSA based representation that provides type safety,
216low-level operations, flexibility, and the capability of representing
217'all' high-level languages cleanly. It is the common code
218representation used throughout all phases of the LLVM compilation
219strategy.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]220</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]221
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]222<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]223<div class="doc_section"> <a name="introduction">Introduction</a> </div>
224<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]225
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]226<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]227
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]228<p>The LLVM code representation is designed to be used in three
Gabor Greif04367bf2007-07-06 22:07:22 +0000[diff] [blame]229different forms: as an in-memory compiler IR, as an on-disk bitcode
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]230representation (suitable for fast loading by a Just-In-Time compiler),
231and as a human readable assembly language representation. This allows
232LLVM to provide a powerful intermediate representation for efficient
233compiler transformations and analysis, while providing a natural means
234to debug and visualize the transformations. The three different forms
235of LLVM are all equivalent. This document describes the human readable
236representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]237
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]238<p>The LLVM representation aims to be light-weight and low-level
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]239while being expressive, typed, and extensible at the same time. It
240aims to be a "universal IR" of sorts, by being at a low enough level
241that high-level ideas may be cleanly mapped to it (similar to how
242microprocessors are "universal IR's", allowing many source languages to
243be mapped to them). By providing type information, LLVM can be used as
244the target of optimizations: for example, through pointer analysis, it
245can be proven that a C automatic variable is never accessed outside of
246the current function... allowing it to be promoted to a simple SSA
247value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]248
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]249</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]250
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]251<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]252<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]253
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]254<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]255
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]256<p>It is important to note that this document describes 'well formed'
257LLVM assembly language. There is a difference between what the parser
258accepts and what is considered 'well formed'. For example, the
259following instruction is syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]260
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]261<div class="doc_code">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]262<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]263%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]264</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]265</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]266
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]267<p>...because the definition of <tt>%x</tt> does not dominate all of
268its uses. The LLVM infrastructure provides a verification pass that may
269be used to verify that an LLVM module is well formed. This pass is
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]270automatically run by the parser after parsing input assembly and by
Gabor Greif04367bf2007-07-06 22:07:22 +0000[diff] [blame]271the optimizer before it outputs bitcode. The violations pointed out
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]272by the verifier pass indicate bugs in transformation passes or input to
273the parser.</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]274</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]275
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]276<!-- Describe the typesetting conventions here. --> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]277
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]278<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]279<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]280<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]281
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]282<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]283
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]284<p>LLVM uses three different forms of identifiers, for different
285purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]286
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]287<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]288 <li>Named values are represented as a string of characters with a '%' prefix.
289 For example, %foo, %DivisionByZero, %a.really.long.identifier. The actual
290 regular expression used is '<tt>%[a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
291 Identifiers which require other characters in their names can be surrounded
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]292 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]293 in a name.</li>
294
295 <li>Unnamed values are represented as an unsigned numeric value with a '%'
296 prefix. For example, %12, %2, %44.</li>
297
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]298 <li>Constants, which are described in a <a href="#constants">section about
299 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]300</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]301
302<p>LLVM requires that values start with a '%' sign for two reasons: Compilers
303don't need to worry about name clashes with reserved words, and the set of
304reserved words may be expanded in the future without penalty. Additionally,
305unnamed identifiers allow a compiler to quickly come up with a temporary
306variable without having to avoid symbol table conflicts.</p>
307
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]308<p>Reserved words in LLVM are very similar to reserved words in other
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]309languages. There are keywords for different opcodes
310('<tt><a href="#i_add">add</a></tt>',
311 '<tt><a href="#i_bitcast">bitcast</a></tt>',
312 '<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]313href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]314and others. These reserved words cannot conflict with variable names, because
315none of them start with a '%' character.</p>
316
317<p>Here is an example of LLVM code to multiply the integer variable
318'<tt>%X</tt>' by 8:</p>
319
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]320<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]321
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]322<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]323<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]324%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]325</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]326</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]327
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]328<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]329
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]330<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]331<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]332%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]333</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]334</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]335
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]336<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]337
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]338<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]339<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]340<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
341<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
342%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]343</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]344</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]345
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]346<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
347important lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]348
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]349<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]350
351 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
352 line.</li>
353
354 <li>Unnamed temporaries are created when the result of a computation is not
355 assigned to a named value.</li>
356
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]357 <li>Unnamed temporaries are numbered sequentially</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]358
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]359</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]360
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]361<p>...and it also shows a convention that we follow in this document. When
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]362demonstrating instructions, we will follow an instruction with a comment that
363defines the type and name of value produced. Comments are shown in italic
364text.</p>
365
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]366</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]367
368<!-- *********************************************************************** -->
369<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
370<!-- *********************************************************************** -->
371
372<!-- ======================================================================= -->
373<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
374</div>
375
376<div class="doc_text">
377
378<p>LLVM programs are composed of "Module"s, each of which is a
379translation unit of the input programs. Each module consists of
380functions, global variables, and symbol table entries. Modules may be
381combined together with the LLVM linker, which merges function (and
382global variable) definitions, resolves forward declarations, and merges
383symbol table entries. Here is an example of the "hello world" module:</p>
384
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]385<div class="doc_code">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]386<pre><i>; Declare the string constant as a global constant...</i>
Chris Lattnera89e5f12007-06-12 17:00:26 +0000[diff] [blame]387<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
388 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]389
390<i>; External declaration of the puts function</i>
Chris Lattnera89e5f12007-06-12 17:00:26 +0000[diff] [blame]391<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]392
393<i>; Definition of main function</i>
Chris Lattnera89e5f12007-06-12 17:00:26 +0000[diff] [blame]394define i32 @main() { <i>; i32()* </i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]395 <i>; Convert [13x i8 ]* to i8 *...</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]396 %cast210 = <a
Chris Lattner6c0955b2007-06-12 17:01:15 +0000[diff] [blame]397 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]398
399 <i>; Call puts function to write out the string to stdout...</i>
400 <a
Chris Lattnera89e5f12007-06-12 17:00:26 +0000[diff] [blame]401 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]402 <a
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]403 href="#i_ret">ret</a> i32 0<br>}<br>
404</pre>
405</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]406
407<p>This example is made up of a <a href="#globalvars">global variable</a>
408named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
409function, and a <a href="#functionstructure">function definition</a>
410for "<tt>main</tt>".</p>
411
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]412<p>In general, a module is made up of a list of global values,
413where both functions and global variables are global values. Global values are
414represented by a pointer to a memory location (in this case, a pointer to an
415array of char, and a pointer to a function), and have one of the following <a
416href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]417
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]418</div>
419
420<!-- ======================================================================= -->
421<div class="doc_subsection">
422 <a name="linkage">Linkage Types</a>
423</div>
424
425<div class="doc_text">
426
427<p>
428All Global Variables and Functions have one of the following types of linkage:
429</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]430
431<dl>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]432
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]433 <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]434
435 <dd>Global values with internal linkage are only directly accessible by
436 objects in the current module. In particular, linking code into a module with
437 an internal global value may cause the internal to be renamed as necessary to
438 avoid collisions. Because the symbol is internal to the module, all
439 references can be updated. This corresponds to the notion of the
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]440 '<tt>static</tt>' keyword in C.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]441 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]442
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]443 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]444
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]445 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
446 the same name when linkage occurs. This is typically used to implement
447 inline functions, templates, or other code which must be generated in each
448 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
449 allowed to be discarded.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]450 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]451
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]452 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]453
454 <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage,
455 except that unreferenced <tt>weak</tt> globals may not be discarded. This is
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]456 used for globals that may be emitted in multiple translation units, but that
457 are not guaranteed to be emitted into every translation unit that uses them.
458 One example of this are common globals in C, such as "<tt>int X;</tt>" at
459 global scope.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]460 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]461
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]462 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]463
464 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
465 pointer to array type. When two global variables with appending linkage are
466 linked together, the two global arrays are appended together. This is the
467 LLVM, typesafe, equivalent of having the system linker append together
468 "sections" with identical names when .o files are linked.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]469 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]470
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]471 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
472 <dd>The semantics of this linkage follow the ELF model: the symbol is weak
473 until linked, if not linked, the symbol becomes null instead of being an
474 undefined reference.
475 </dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]476
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]477 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]478
479 <dd>If none of the above identifiers are used, the global is externally
480 visible, meaning that it participates in linkage and can be used to resolve
481 external symbol references.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]482 </dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]483</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]484
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]485 <p>
486 The next two types of linkage are targeted for Microsoft Windows platform
487 only. They are designed to support importing (exporting) symbols from (to)
488 DLLs.
489 </p>
490
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]491 <dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]492 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
493
494 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
495 or variable via a global pointer to a pointer that is set up by the DLL
496 exporting the symbol. On Microsoft Windows targets, the pointer name is
497 formed by combining <code>_imp__</code> and the function or variable name.
498 </dd>
499
500 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
501
502 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
503 pointer to a pointer in a DLL, so that it can be referenced with the
504 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
505 name is formed by combining <code>_imp__</code> and the function or variable
506 name.
507 </dd>
508
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]509</dl>
510
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]511<p><a name="linkage_external"></a>For example, since the "<tt>.LC0</tt>"
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]512variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
513variable and was linked with this one, one of the two would be renamed,
514preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
515external (i.e., lacking any linkage declarations), they are accessible
Reid Spencerac8d2762007-01-05 00:59:10 +0000[diff] [blame]516outside of the current module.</p>
517<p>It is illegal for a function <i>declaration</i>
518to have any linkage type other than "externally visible", <tt>dllimport</tt>,
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]519or <tt>extern_weak</tt>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]520<p>Aliases can have only <tt>external</tt>, <tt>internal</tt> and <tt>weak</tt>
521linkages.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]522</div>
523
524<!-- ======================================================================= -->
525<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]526 <a name="callingconv">Calling Conventions</a>
527</div>
528
529<div class="doc_text">
530
531<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
532and <a href="#i_invoke">invokes</a> can all have an optional calling convention
533specified for the call. The calling convention of any pair of dynamic
534caller/callee must match, or the behavior of the program is undefined. The
535following calling conventions are supported by LLVM, and more may be added in
536the future:</p>
537
538<dl>
539 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
540
541 <dd>This calling convention (the default if no other calling convention is
542 specified) matches the target C calling conventions. This calling convention
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]543 supports varargs function calls and tolerates some mismatch in the declared
Reid Spencerc28d2bc2006-12-31 21:30:18 +0000[diff] [blame]544 prototype and implemented declaration of the function (as does normal C).
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]545 </dd>
546
547 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
548
549 <dd>This calling convention attempts to make calls as fast as possible
550 (e.g. by passing things in registers). This calling convention allows the
551 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner8cdc5bc2005-05-06 23:08:23 +0000[diff] [blame]552 without having to conform to an externally specified ABI. Implementations of
553 this convention should allow arbitrary tail call optimization to be supported.
554 This calling convention does not support varargs and requires the prototype of
555 all callees to exactly match the prototype of the function definition.
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]556 </dd>
557
558 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
559
560 <dd>This calling convention attempts to make code in the caller as efficient
561 as possible under the assumption that the call is not commonly executed. As
562 such, these calls often preserve all registers so that the call does not break
563 any live ranges in the caller side. This calling convention does not support
564 varargs and requires the prototype of all callees to exactly match the
565 prototype of the function definition.
566 </dd>
567
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]568 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]569
570 <dd>Any calling convention may be specified by number, allowing
571 target-specific calling conventions to be used. Target specific calling
572 conventions start at 64.
573 </dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]574</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]575
576<p>More calling conventions can be added/defined on an as-needed basis, to
577support pascal conventions or any other well-known target-independent
578convention.</p>
579
580</div>
581
582<!-- ======================================================================= -->
583<div class="doc_subsection">
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]584 <a name="visibility">Visibility Styles</a>
585</div>
586
587<div class="doc_text">
588
589<p>
590All Global Variables and Functions have one of the following visibility styles:
591</p>
592
593<dl>
594 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
595
596 <dd>On ELF, default visibility means that the declaration is visible to other
597 modules and, in shared libraries, means that the declared entity may be
598 overridden. On Darwin, default visibility means that the declaration is
599 visible to other modules. Default visibility corresponds to "external
600 linkage" in the language.
601 </dd>
602
603 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
604
605 <dd>Two declarations of an object with hidden visibility refer to the same
606 object if they are in the same shared object. Usually, hidden visibility
607 indicates that the symbol will not be placed into the dynamic symbol table,
608 so no other module (executable or shared library) can reference it
609 directly.
610 </dd>
611
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]612 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
613
614 <dd>On ELF, protected visibility indicates that the symbol will be placed in
615 the dynamic symbol table, but that references within the defining module will
616 bind to the local symbol. That is, the symbol cannot be overridden by another
617 module.
618 </dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]619</dl>
620
621</div>
622
623<!-- ======================================================================= -->
624<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]625 <a name="globalvars">Global Variables</a>
626</div>
627
628<div class="doc_text">
629
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]630<p>Global variables define regions of memory allocated at compilation time
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]631instead of run-time. Global variables may optionally be initialized, may have
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]632an explicit section to be placed in, and may have an optional explicit alignment
633specified. A variable may be defined as "thread_local", which means that it
634will not be shared by threads (each thread will have a separated copy of the
635variable). A variable may be defined as a global "constant," which indicates
636that the contents of the variable will <b>never</b> be modified (enabling better
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]637optimization, allowing the global data to be placed in the read-only section of
638an executable, etc). Note that variables that need runtime initialization
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]639cannot be marked "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]640
641<p>
642LLVM explicitly allows <em>declarations</em> of global variables to be marked
643constant, even if the final definition of the global is not. This capability
644can be used to enable slightly better optimization of the program, but requires
645the language definition to guarantee that optimizations based on the
646'constantness' are valid for the translation units that do not include the
647definition.
648</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]649
650<p>As SSA values, global variables define pointer values that are in
651scope (i.e. they dominate) all basic blocks in the program. Global
652variables always define a pointer to their "content" type because they
653describe a region of memory, and all memory objects in LLVM are
654accessed through pointers.</p>
655
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]656<p>LLVM allows an explicit section to be specified for globals. If the target
657supports it, it will emit globals to the section specified.</p>
658
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]659<p>An explicit alignment may be specified for a global. If not present, or if
660the alignment is set to zero, the alignment of the global is set by the target
661to whatever it feels convenient. If an explicit alignment is specified, the
662global is forced to have at least that much alignment. All alignments must be
663a power of 2.</p>
664
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]665<p>For example, the following defines a global with an initializer, section,
666 and alignment:</p>
667
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]668<div class="doc_code">
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]669<pre>
Chris Lattner3e63a9d2007-07-13 20:01:46 +0000[diff] [blame]670@G = constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]671</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]672</div>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]673
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]674</div>
675
676
677<!-- ======================================================================= -->
678<div class="doc_subsection">
679 <a name="functionstructure">Functions</a>
680</div>
681
682<div class="doc_text">
683
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]684<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
685an optional <a href="#linkage">linkage type</a>, an optional
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]686<a href="#visibility">visibility style</a>, an optional
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]687<a href="#callingconv">calling convention</a>, a return type, an optional
688<a href="#paramattrs">parameter attribute</a> for the return type, a function
689name, a (possibly empty) argument list (each with optional
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]690<a href="#paramattrs">parameter attributes</a>), an optional section, an
691optional alignment, an opening curly brace, a list of basic blocks, and a
692closing curly brace.
693
694LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
695optional <a href="#linkage">linkage type</a>, an optional
696<a href="#visibility">visibility style</a>, an optional
697<a href="#callingconv">calling convention</a>, a return type, an optional
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]698<a href="#paramattrs">parameter attribute</a> for the return type, a function
699name, a possibly empty list of arguments, and an optional alignment.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]700
701<p>A function definition contains a list of basic blocks, forming the CFG for
702the function. Each basic block may optionally start with a label (giving the
703basic block a symbol table entry), contains a list of instructions, and ends
704with a <a href="#terminators">terminator</a> instruction (such as a branch or
705function return).</p>
706
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]707<p>The first basic block in a function is special in two ways: it is immediately
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]708executed on entrance to the function, and it is not allowed to have predecessor
709basic blocks (i.e. there can not be any branches to the entry block of a
710function). Because the block can have no predecessors, it also cannot have any
711<a href="#i_phi">PHI nodes</a>.</p>
712
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]713<p>LLVM allows an explicit section to be specified for functions. If the target
714supports it, it will emit functions to the section specified.</p>
715
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]716<p>An explicit alignment may be specified for a function. If not present, or if
717the alignment is set to zero, the alignment of the function is set by the target
718to whatever it feels convenient. If an explicit alignment is specified, the
719function is forced to have at least that much alignment. All alignments must be
720a power of 2.</p>
721
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]722</div>
723
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]724
725<!-- ======================================================================= -->
726<div class="doc_subsection">
727 <a name="aliasstructure">Aliases</a>
728</div>
729<div class="doc_text">
730 <p>Aliases act as "second name" for the aliasee value (which can be either
Anton Korobeynikova80e1182007-04-28 13:45:00 +0000[diff] [blame]731 function or global variable or bitcast of global value). Aliases may have an
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]732 optional <a href="#linkage">linkage type</a>, and an
733 optional <a href="#visibility">visibility style</a>.</p>
734
735 <h5>Syntax:</h5>
736
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]737<div class="doc_code">
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]738<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]739@&lt;Name&gt; = [Linkage] [Visibility] alias &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]740</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]741</div>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]742
743</div>
744
745
746
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]747<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]748<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
749<div class="doc_text">
750 <p>The return type and each parameter of a function type may have a set of
751 <i>parameter attributes</i> associated with them. Parameter attributes are
752 used to communicate additional information about the result or parameters of
753 a function. Parameter attributes are considered to be part of the function
754 type so two functions types that differ only by the parameter attributes
755 are different function types.</p>
756
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]757 <p>Parameter attributes are simple keywords that follow the type specified. If
758 multiple parameter attributes are needed, they are space separated. For
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]759 example:</p>
760
761<div class="doc_code">
762<pre>
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame^]763%someFunc = i16 (i8 signext %someParam) zeroext
764%someFunc = i16 (i8 zeroext %someParam) zeroext
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]765</pre>
766</div>
767
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]768 <p>Note that the two function types above are unique because the parameter has
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame^]769 a different attribute (<tt>signext</tt> in the first one, <tt>zeroext</tt> in
770 the second). Also note that the attribute for the function result
771 (<tt>zeroext</tt>) comes immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]772
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]773 <p>Currently, only the following parameter attributes are defined:</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]774 <dl>
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame^]775 <dt><tt>zeroext</tt></dt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]776 <dd>This indicates that the parameter should be zero extended just before
777 a call to this function.</dd>
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame^]778 <dt><tt>signext</tt></dt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]779 <dd>This indicates that the parameter should be sign extended just before
780 a call to this function.</dd>
Anton Korobeynikov34d6dea2007-01-28 14:30:45 +0000[diff] [blame]781 <dt><tt>inreg</tt></dt>
782 <dd>This indicates that the parameter should be placed in register (if
Anton Korobeynikov66a8c8c2007-01-28 15:27:21 +0000[diff] [blame]783 possible) during assembling function call. Support for this attribute is
784 target-specific</dd>
Anton Korobeynikov34d6dea2007-01-28 14:30:45 +0000[diff] [blame]785 <dt><tt>sret</tt></dt>
Anton Korobeynikov66a8c8c2007-01-28 15:27:21 +0000[diff] [blame]786 <dd>This indicates that the parameter specifies the address of a structure
Reid Spencer67606122007-03-22 02:02:11 +0000[diff] [blame]787 that is the return value of the function in the source program.</dd>
Zhou Shengfebca342007-06-05 05:28:26 +0000[diff] [blame]788 <dt><tt>noalias</tt></dt>
789 <dd>This indicates that the parameter not alias any other object or any
790 other "noalias" objects during the function call.
Reid Spencer2dc52012007-03-22 02:18:56 +0000[diff] [blame]791 <dt><tt>noreturn</tt></dt>
792 <dd>This function attribute indicates that the function never returns. This
793 indicates to LLVM that every call to this function should be treated as if
794 an <tt>unreachable</tt> instruction immediately followed the call.</dd>
Reid Spencer67606122007-03-22 02:02:11 +0000[diff] [blame]795 <dt><tt>nounwind</tt></dt>
796 <dd>This function attribute indicates that the function type does not use
797 the unwind instruction and does not allow stack unwinding to propagate
798 through it.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]799 </dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]800
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]801</div>
802
803<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]804<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]805 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]806</div>
807
808<div class="doc_text">
809<p>
810Modules may contain "module-level inline asm" blocks, which corresponds to the
811GCC "file scope inline asm" blocks. These blocks are internally concatenated by
812LLVM and treated as a single unit, but may be separated in the .ll file if
813desired. The syntax is very simple:
814</p>
815
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]816<div class="doc_code">
817<pre>
818module asm "inline asm code goes here"
819module asm "more can go here"
820</pre>
821</div>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]822
823<p>The strings can contain any character by escaping non-printable characters.
824 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
825 for the number.
826</p>
827
828<p>
829 The inline asm code is simply printed to the machine code .s file when
830 assembly code is generated.
831</p>
832</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]833
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]834<!-- ======================================================================= -->
835<div class="doc_subsection">
836 <a name="datalayout">Data Layout</a>
837</div>
838
839<div class="doc_text">
840<p>A module may specify a target specific data layout string that specifies how
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]841data is to be laid out in memory. The syntax for the data layout is simply:</p>
842<pre> target datalayout = "<i>layout specification</i>"</pre>
843<p>The <i>layout specification</i> consists of a list of specifications
844separated by the minus sign character ('-'). Each specification starts with a
845letter and may include other information after the letter to define some
846aspect of the data layout. The specifications accepted are as follows: </p>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]847<dl>
848 <dt><tt>E</tt></dt>
849 <dd>Specifies that the target lays out data in big-endian form. That is, the
850 bits with the most significance have the lowest address location.</dd>
851 <dt><tt>e</tt></dt>
852 <dd>Specifies that hte target lays out data in little-endian form. That is,
853 the bits with the least significance have the lowest address location.</dd>
854 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
855 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
856 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
857 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
858 too.</dd>
859 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
860 <dd>This specifies the alignment for an integer type of a given bit
861 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
862 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
863 <dd>This specifies the alignment for a vector type of a given bit
864 <i>size</i>.</dd>
865 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
866 <dd>This specifies the alignment for a floating point type of a given bit
867 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
868 (double).</dd>
869 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
870 <dd>This specifies the alignment for an aggregate type of a given bit
871 <i>size</i>.</dd>
872</dl>
873<p>When constructing the data layout for a given target, LLVM starts with a
874default set of specifications which are then (possibly) overriden by the
875specifications in the <tt>datalayout</tt> keyword. The default specifications
876are given in this list:</p>
877<ul>
878 <li><tt>E</tt> - big endian</li>
879 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
880 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
881 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
882 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
883 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
884 <li><tt>i64:32:64</tt> - i64 has abi alignment of 32-bits but preferred
885 alignment of 64-bits</li>
886 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
887 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
888 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
889 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
890 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
891</ul>
892<p>When llvm is determining the alignment for a given type, it uses the
893following rules:
894<ol>
895 <li>If the type sought is an exact match for one of the specifications, that
896 specification is used.</li>
897 <li>If no match is found, and the type sought is an integer type, then the
898 smallest integer type that is larger than the bitwidth of the sought type is
899 used. If none of the specifications are larger than the bitwidth then the the
900 largest integer type is used. For example, given the default specifications
901 above, the i7 type will use the alignment of i8 (next largest) while both
902 i65 and i256 will use the alignment of i64 (largest specified).</li>
903 <li>If no match is found, and the type sought is a vector type, then the
904 largest vector type that is smaller than the sought vector type will be used
905 as a fall back. This happens because <128 x double> can be implemented in
906 terms of 64 <2 x double>, for example.</li>
907</ol>
908</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]909
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]910<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]911<div class="doc_section"> <a name="typesystem">Type System</a> </div>
912<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]913
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]914<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]915
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]916<p>The LLVM type system is one of the most important features of the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]917intermediate representation. Being typed enables a number of
918optimizations to be performed on the IR directly, without having to do
919extra analyses on the side before the transformation. A strong type
920system makes it easier to read the generated code and enables novel
921analyses and transformations that are not feasible to perform on normal
922three address code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]923
924</div>
925
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]926<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]927<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]928<div class="doc_text">
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]929<p>The primitive types are the fundamental building blocks of the LLVM
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]930system. The current set of primitive types is as follows:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]931
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]932<table class="layout">
933 <tr class="layout">
934 <td class="left">
935 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]936 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]937 <tr><th>Type</th><th>Description</th></tr>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]938 <tr><td><tt><a name="t_void">void</a></tt></td><td>No value</td></tr>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]939 <tr><td><tt>label</tt></td><td>Branch destination</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]940 </tbody>
941 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]942 </td>
943 <td class="right">
944 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]945 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]946 <tr><th>Type</th><th>Description</th></tr>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]947 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]948 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]949 </tbody>
950 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]951 </td>
952 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]953</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]954</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]955
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]956<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]957<div class="doc_subsubsection"> <a name="t_classifications">Type
958Classifications</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]959<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]960<p>These different primitive types fall into a few useful
961classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]962
963<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]964 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]965 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]966 <tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]967 <td><a name="t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]968 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]969 </tr>
970 <tr>
971 <td><a name="t_floating">floating point</a></td>
972 <td><tt>float, double</tt></td>
973 </tr>
974 <tr>
975 <td><a name="t_firstclass">first class</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]976 <td><tt>i1, ..., float, double, <br/>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]977 <a href="#t_pointer">pointer</a>,<a href="#t_vector">vector</a></tt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]978 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]979 </tr>
980 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]981</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]982
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]983<p>The <a href="#t_firstclass">first class</a> types are perhaps the
984most important. Values of these types are the only ones which can be
985produced by instructions, passed as arguments, or used as operands to
986instructions. This means that all structures and arrays must be
987manipulated either by pointer or by component.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]988</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]989
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]990<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]991<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]992
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]993<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]994
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]995<p>The real power in LLVM comes from the derived types in the system.
996This is what allows a programmer to represent arrays, functions,
997pointers, and other useful types. Note that these derived types may be
998recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]999
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1000</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1001
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1002<!-- _______________________________________________________________________ -->
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1003<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1004
1005<div class="doc_text">
1006
1007<h5>Overview:</h5>
1008<p>The integer type is a very simple derived type that simply specifies an
1009arbitrary bit width for the integer type desired. Any bit width from 1 bit to
10102^23-1 (about 8 million) can be specified.</p>
1011
1012<h5>Syntax:</h5>
1013
1014<pre>
1015 iN
1016</pre>
1017
1018<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1019value.</p>
1020
1021<h5>Examples:</h5>
1022<table class="layout">
1023 <tr class="layout">
1024 <td class="left">
1025 <tt>i1</tt><br/>
1026 <tt>i4</tt><br/>
1027 <tt>i8</tt><br/>
1028 <tt>i16</tt><br/>
1029 <tt>i32</tt><br/>
1030 <tt>i42</tt><br/>
1031 <tt>i64</tt><br/>
1032 <tt>i1942652</tt><br/>
1033 </td>
1034 <td class="left">
1035 A boolean integer of 1 bit<br/>
1036 A nibble sized integer of 4 bits.<br/>
1037 A byte sized integer of 8 bits.<br/>
1038 A half word sized integer of 16 bits.<br/>
1039 A word sized integer of 32 bits.<br/>
1040 An integer whose bit width is the answer. <br/>
1041 A double word sized integer of 64 bits.<br/>
1042 A really big integer of over 1 million bits.<br/>
1043 </td>
1044 </tr>
1045</table>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1046</div>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1047
1048<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1049<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1050
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1051<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1052
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1053<h5>Overview:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1054
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1055<p>The array type is a very simple derived type that arranges elements
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1056sequentially in memory. The array type requires a size (number of
1057elements) and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1058
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1059<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1060
1061<pre>
1062 [&lt;# elements&gt; x &lt;elementtype&gt;]
1063</pre>
1064
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1065<p>The number of elements is a constant integer value; elementtype may
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1066be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1067
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1068<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1069<table class="layout">
1070 <tr class="layout">
1071 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1072 <tt>[40 x i32 ]</tt><br/>
1073 <tt>[41 x i32 ]</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1074 <tt>[40 x i8]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1075 </td>
1076 <td class="left">
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1077 Array of 40 32-bit integer values.<br/>
1078 Array of 41 32-bit integer values.<br/>
1079 Array of 40 8-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1080 </td>
1081 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1082</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1083<p>Here are some examples of multidimensional arrays:</p>
1084<table class="layout">
1085 <tr class="layout">
1086 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1087 <tt>[3 x [4 x i32]]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1088 <tt>[12 x [10 x float]]</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1089 <tt>[2 x [3 x [4 x i16]]]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1090 </td>
1091 <td class="left">
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1092 3x4 array of 32-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1093 12x10 array of single precision floating point values.<br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1094 2x3x4 array of 16-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1095 </td>
1096 </tr>
1097</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1098
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1099<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1100length array. Normally, accesses past the end of an array are undefined in
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1101LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1102As a special case, however, zero length arrays are recognized to be variable
1103length. This allows implementation of 'pascal style arrays' with the LLVM
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1104type "{ i32, [0 x float]}", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1105
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1106</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1107
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1108<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1109<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1110<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1111<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1112<p>The function type can be thought of as a function signature. It
1113consists of a return type and a list of formal parameter types.
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]1114Function types are usually used to build virtual function tables
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1115(which are structures of pointers to functions), for indirect function
1116calls, and when defining a function.</p>
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]1117<p>
1118The return type of a function type cannot be an aggregate type.
1119</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1120<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1121<pre> &lt;returntype&gt; (&lt;parameter list&gt;)<br></pre>
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1122<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]1123specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1124which indicates that the function takes a variable number of arguments.
1125Variable argument functions can access their arguments with the <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1126 href="#int_varargs">variable argument handling intrinsic</a> functions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1127<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1128<table class="layout">
1129 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1130 <td class="left"><tt>i32 (i32)</tt></td>
1131 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1132 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1133 </tr><tr class="layout">
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame^]1134 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1135 </tt></td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1136 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1137 an <tt>i16</tt> that should be sign extended and a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1138 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1139 <tt>float</tt>.
1140 </td>
1141 </tr><tr class="layout">
1142 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1143 <td class="left">A vararg function that takes at least one
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1144 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1145 which returns an integer. This is the signature for <tt>printf</tt> in
1146 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1147 </td>
1148 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1149</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1150
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1151</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1152<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1153<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1154<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1155<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1156<p>The structure type is used to represent a collection of data members
1157together in memory. The packing of the field types is defined to match
1158the ABI of the underlying processor. The elements of a structure may
1159be any type that has a size.</p>
1160<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1161and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1162field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1163instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1164<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1165<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1166<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1167<table class="layout">
1168 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1169 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1170 <td class="left">A triple of three <tt>i32</tt> values</td>
1171 </tr><tr class="layout">
1172 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1173 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1174 second element is a <a href="#t_pointer">pointer</a> to a
1175 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1176 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1177 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1178</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1179</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1180
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1181<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1182<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1183</div>
1184<div class="doc_text">
1185<h5>Overview:</h5>
1186<p>The packed structure type is used to represent a collection of data members
1187together in memory. There is no padding between fields. Further, the alignment
1188of a packed structure is 1 byte. The elements of a packed structure may
1189be any type that has a size.</p>
1190<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1191and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1192field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1193instruction.</p>
1194<h5>Syntax:</h5>
1195<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1196<h5>Examples:</h5>
1197<table class="layout">
1198 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1199 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1200 <td class="left">A triple of three <tt>i32</tt> values</td>
1201 </tr><tr class="layout">
1202 <td class="left"><tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}&nbsp;&gt;</tt></td>
1203 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1204 second element is a <a href="#t_pointer">pointer</a> to a
1205 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1206 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1207 </tr>
1208</table>
1209</div>
1210
1211<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1212<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1213<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1214<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1215<p>As in many languages, the pointer type represents a pointer or
1216reference to another object, which must live in memory.</p>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1217<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1218<pre> &lt;type&gt; *<br></pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1219<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1220<table class="layout">
1221 <tr class="layout">
1222 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1223 <tt>[4x i32]*</tt><br/>
1224 <tt>i32 (i32 *) *</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1225 </td>
1226 <td class="left">
1227 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]1228 four <tt>i32</tt> values<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1229 A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1230 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
1231 <tt>i32</tt>.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1232 </td>
1233 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1234</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1235</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1236
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1237<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1238<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1239<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1240
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1241<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1242
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1243<p>A vector type is a simple derived type that represents a vector
1244of elements. Vector types are used when multiple primitive data
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1245are operated in parallel using a single instruction (SIMD).
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1246A vector type requires a size (number of
Chris Lattnerb8d172f2005-11-10 01:44:22 +0000[diff] [blame]1247elements) and an underlying primitive data type. Vectors must have a power
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1248of two length (1, 2, 4, 8, 16 ...). Vector types are
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1249considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1250
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1251<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1252
1253<pre>
1254 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1255</pre>
1256
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1257<p>The number of elements is a constant integer value; elementtype may
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]1258be any integer or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1259
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1260<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1261
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1262<table class="layout">
1263 <tr class="layout">
1264 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1265 <tt>&lt;4 x i32&gt;</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1266 <tt>&lt;8 x float&gt;</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1267 <tt>&lt;2 x i64&gt;</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1268 </td>
1269 <td class="left">
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1270 Vector of 4 32-bit integer values.<br/>
1271 Vector of 8 floating-point values.<br/>
1272 Vector of 2 64-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1273 </td>
1274 </tr>
1275</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1276</div>
1277
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1278<!-- _______________________________________________________________________ -->
1279<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1280<div class="doc_text">
1281
1282<h5>Overview:</h5>
1283
1284<p>Opaque types are used to represent unknown types in the system. This
1285corresponds (for example) to the C notion of a foward declared structure type.
1286In LLVM, opaque types can eventually be resolved to any type (not just a
1287structure type).</p>
1288
1289<h5>Syntax:</h5>
1290
1291<pre>
1292 opaque
1293</pre>
1294
1295<h5>Examples:</h5>
1296
1297<table class="layout">
1298 <tr class="layout">
1299 <td class="left">
1300 <tt>opaque</tt>
1301 </td>
1302 <td class="left">
1303 An opaque type.<br/>
1304 </td>
1305 </tr>
1306</table>
1307</div>
1308
1309
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1310<!-- *********************************************************************** -->
1311<div class="doc_section"> <a name="constants">Constants</a> </div>
1312<!-- *********************************************************************** -->
1313
1314<div class="doc_text">
1315
1316<p>LLVM has several different basic types of constants. This section describes
1317them all and their syntax.</p>
1318
1319</div>
1320
1321<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1322<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1323
1324<div class="doc_text">
1325
1326<dl>
1327 <dt><b>Boolean constants</b></dt>
1328
1329 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1330 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1331 </dd>
1332
1333 <dt><b>Integer constants</b></dt>
1334
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1335 <dd>Standard integers (such as '4') are constants of the <a
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1336 href="#t_integer">integer</a> type. Negative numbers may be used with
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1337 integer types.
1338 </dd>
1339
1340 <dt><b>Floating point constants</b></dt>
1341
1342 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1343 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1344 notation (see below). Floating point constants must have a <a
1345 href="#t_floating">floating point</a> type. </dd>
1346
1347 <dt><b>Null pointer constants</b></dt>
1348
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1349 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1350 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1351
1352</dl>
1353
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1354<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1355of floating point constants. For example, the form '<tt>double
13560x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
13574.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1358(and the only time that they are generated by the disassembler) is when a
1359floating point constant must be emitted but it cannot be represented as a
1360decimal floating point number. For example, NaN's, infinities, and other
1361special values are represented in their IEEE hexadecimal format so that
1362assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1363
1364</div>
1365
1366<!-- ======================================================================= -->
1367<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1368</div>
1369
1370<div class="doc_text">
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1371<p>Aggregate constants arise from aggregation of simple constants
1372and smaller aggregate constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1373
1374<dl>
1375 <dt><b>Structure constants</b></dt>
1376
1377 <dd>Structure constants are represented with notation similar to structure
1378 type definitions (a comma separated list of elements, surrounded by braces
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1379 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* %G }</tt>",
Chris Lattner3e63a9d2007-07-13 20:01:46 +0000[diff] [blame]1380 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]1381 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1382 types of elements must match those specified by the type.
1383 </dd>
1384
1385 <dt><b>Array constants</b></dt>
1386
1387 <dd>Array constants are represented with notation similar to array type
1388 definitions (a comma separated list of elements, surrounded by square brackets
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1389 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1390 constants must have <a href="#t_array">array type</a>, and the number and
1391 types of elements must match those specified by the type.
1392 </dd>
1393
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1394 <dt><b>Vector constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1395
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1396 <dd>Vector constants are represented with notation similar to vector type
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1397 definitions (a comma separated list of elements, surrounded by
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1398 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]1399 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1400 href="#t_vector">vector type</a>, and the number and types of elements must
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1401 match those specified by the type.
1402 </dd>
1403
1404 <dt><b>Zero initialization</b></dt>
1405
1406 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1407 value to zero of <em>any</em> type, including scalar and aggregate types.
1408 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]1409 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1410 initializers.
1411 </dd>
1412</dl>
1413
1414</div>
1415
1416<!-- ======================================================================= -->
1417<div class="doc_subsection">
1418 <a name="globalconstants">Global Variable and Function Addresses</a>
1419</div>
1420
1421<div class="doc_text">
1422
1423<p>The addresses of <a href="#globalvars">global variables</a> and <a
1424href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1425constants. These constants are explicitly referenced when the <a
1426href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1427href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1428file:</p>
1429
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1430<div class="doc_code">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1431<pre>
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]1432@X = global i32 17
1433@Y = global i32 42
1434@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1435</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1436</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1437
1438</div>
1439
1440<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1441<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1442<div class="doc_text">
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1443 <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]1444 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1445 a constant is permitted.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1446
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1447 <p>Undefined values indicate to the compiler that the program is well defined
1448 no matter what value is used, giving the compiler more freedom to optimize.
1449 </p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1450</div>
1451
1452<!-- ======================================================================= -->
1453<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1454</div>
1455
1456<div class="doc_text">
1457
1458<p>Constant expressions are used to allow expressions involving other constants
1459to be used as constants. Constant expressions may be of any <a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1460href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1461that does not have side effects (e.g. load and call are not supported). The
1462following is the syntax for constant expressions:</p>
1463
1464<dl>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1465 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1466 <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]1467 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1468
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1469 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1470 <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]1471 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]1472
1473 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1474 <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]1475 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]1476
1477 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1478 <dd>Truncate a floating point constant to another floating point type. The
1479 size of CST must be larger than the size of TYPE. Both types must be
1480 floating point.</dd>
1481
1482 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1483 <dd>Floating point extend a constant to another type. The size of CST must be
1484 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1485
1486 <dt><b><tt>fp2uint ( CST to TYPE )</tt></b></dt>
1487 <dd>Convert a floating point constant to the corresponding unsigned integer
1488 constant. TYPE must be an integer type. CST must be floating point. If the
1489 value won't fit in the integer type, the results are undefined.</dd>
1490
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1491 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1492 <dd>Convert a floating point constant to the corresponding signed integer
1493 constant. TYPE must be an integer type. CST must be floating point. If the
1494 value won't fit in the integer type, the results are undefined.</dd>
1495
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1496 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1497 <dd>Convert an unsigned integer constant to the corresponding floating point
1498 constant. TYPE must be floating point. CST must be of integer type. If the
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]1499 value won't fit in the floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1500
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1501 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1502 <dd>Convert a signed integer constant to the corresponding floating point
1503 constant. TYPE must be floating point. CST must be of integer type. If the
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]1504 value won't fit in the floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1505
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]1506 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1507 <dd>Convert a pointer typed constant to the corresponding integer constant
1508 TYPE must be an integer type. CST must be of pointer type. The CST value is
1509 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1510
1511 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1512 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1513 pointer type. CST must be of integer type. The CST value is zero extended,
1514 truncated, or unchanged to make it fit in a pointer size. This one is
1515 <i>really</i> dangerous!</dd>
1516
1517 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1518 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1519 identical (same number of bits). The conversion is done as if the CST value
1520 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]1521 with this operator, just the type. This can be used for conversion of
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1522 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]1523 pointers it is only valid to cast to another pointer type.
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1524 </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1525
1526 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1527
1528 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1529 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1530 instruction, the index list may have zero or more indexes, which are required
1531 to make sense for the type of "CSTPTR".</dd>
1532
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1533 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1534
1535 <dd>Perform the <a href="#i_select">select operation</a> on
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1536 constants.</dd>
1537
1538 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1539 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1540
1541 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1542 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1543
1544 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1545
1546 <dd>Perform the <a href="#i_extractelement">extractelement
1547 operation</a> on constants.
1548
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1549 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1550
1551 <dd>Perform the <a href="#i_insertelement">insertelement
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1552 operation</a> on constants.</dd>
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1553
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1554
1555 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1556
1557 <dd>Perform the <a href="#i_shufflevector">shufflevector
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1558 operation</a> on constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1559
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1560 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1561
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1562 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1563 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1564 binary</a> operations. The constraints on operands are the same as those for
1565 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1566 values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1567</dl>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1568</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]1569
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1570<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1571<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1572<!-- *********************************************************************** -->
1573
1574<!-- ======================================================================= -->
1575<div class="doc_subsection">
1576<a name="inlineasm">Inline Assembler Expressions</a>
1577</div>
1578
1579<div class="doc_text">
1580
1581<p>
1582LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1583Module-Level Inline Assembly</a>) through the use of a special value. This
1584value represents the inline assembler as a string (containing the instructions
1585to emit), a list of operand constraints (stored as a string), and a flag that
1586indicates whether or not the inline asm expression has side effects. An example
1587inline assembler expression is:
1588</p>
1589
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1590<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1591<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1592i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1593</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1594</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1595
1596<p>
1597Inline assembler expressions may <b>only</b> be used as the callee operand of
1598a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1599</p>
1600
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1601<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1602<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1603%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]1604</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1605</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1606
1607<p>
1608Inline asms with side effects not visible in the constraint list must be marked
1609as having side effects. This is done through the use of the
1610'<tt>sideeffect</tt>' keyword, like so:
1611</p>
1612
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1613<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1614<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1615call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1616</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1617</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1618
1619<p>TODO: The format of the asm and constraints string still need to be
1620documented here. Constraints on what can be done (e.g. duplication, moving, etc
1621need to be documented).
1622</p>
1623
1624</div>
1625
1626<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1627<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1628<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1629
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1630<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1631
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1632<p>The LLVM instruction set consists of several different
1633classifications of instructions: <a href="#terminators">terminator
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1634instructions</a>, <a href="#binaryops">binary instructions</a>,
1635<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1636 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1637instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1638
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1639</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1640
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1641<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1642<div class="doc_subsection"> <a name="terminators">Terminator
1643Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1644
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1645<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1646
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1647<p>As mentioned <a href="#functionstructure">previously</a>, every
1648basic block in a program ends with a "Terminator" instruction, which
1649indicates which block should be executed after the current block is
1650finished. These terminator instructions typically yield a '<tt>void</tt>'
1651value: they produce control flow, not values (the one exception being
1652the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1653<p>There are six different terminator instructions: the '<a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1654 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1655instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1656the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1657 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1658 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1659
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1660</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1661
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1662<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1663<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1664Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1665<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1666<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1667<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]1668 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1669</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1670<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1671<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1672value) from a function back to the caller.</p>
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]1673<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1674returns a value and then causes control flow, and one that just causes
1675control flow to occur.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1676<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1677<p>The '<tt>ret</tt>' instruction may return any '<a
1678 href="#t_firstclass">first class</a>' type. Notice that a function is
1679not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
1680instruction inside of the function that returns a value that does not
1681match the return type of the function.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1682<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1683<p>When the '<tt>ret</tt>' instruction is executed, control flow
1684returns back to the calling function's context. If the caller is a "<a
John Criswellfa081872004-06-25 15:16:57 +0000[diff] [blame]1685 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1686the instruction after the call. If the caller was an "<a
1687 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1688at the beginning of the "normal" destination block. If the instruction
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1689returns a value, that value shall set the call or invoke instruction's
1690return value.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1691<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1692<pre> ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1693 ret void <i>; Return from a void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1694</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1695</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1696<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1697<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1698<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1699<h5>Syntax:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1700<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]1701</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1702<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1703<p>The '<tt>br</tt>' instruction is used to cause control flow to
1704transfer to a different basic block in the current function. There are
1705two forms of this instruction, corresponding to a conditional branch
1706and an unconditional branch.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1707<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1708<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1709single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1710unconditional form of the '<tt>br</tt>' instruction takes a single
1711'<tt>label</tt>' value as a target.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1712<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1713<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1714argument is evaluated. If the value is <tt>true</tt>, control flows
1715to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1716control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1717<h5>Example:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1718<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]1719 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]1720</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1721<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1722<div class="doc_subsubsection">
1723 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1724</div>
1725
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1726<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1727<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1728
1729<pre>
1730 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1731</pre>
1732
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1733<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1734
1735<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1736several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1737instruction, allowing a branch to occur to one of many possible
1738destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1739
1740
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1741<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1742
1743<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1744comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1745an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1746table is not allowed to contain duplicate constant entries.</p>
1747
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1748<h5>Semantics:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1749
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1750<p>The <tt>switch</tt> instruction specifies a table of values and
1751destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1752table is searched for the given value. If the value is found, control flow is
1753transfered to the corresponding destination; otherwise, control flow is
1754transfered to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1755
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1756<h5>Implementation:</h5>
1757
1758<p>Depending on properties of the target machine and the particular
1759<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1760ways. For example, it could be generated as a series of chained conditional
1761branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1762
1763<h5>Example:</h5>
1764
1765<pre>
1766 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1767 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1768 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1769
1770 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1771 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1772
1773 <i>; Implement a jump table:</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1774 switch i32 %val, label %otherwise [ i32 0, label %onzero
1775 i32 1, label %onone
1776 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1777</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1778</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1779
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1780<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1781<div class="doc_subsubsection">
1782 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1783</div>
1784
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1785<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1786
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1787<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1788
1789<pre>
1790 &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]1791 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1792</pre>
1793
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1794<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1795
1796<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1797function, with the possibility of control flow transfer to either the
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1798'<tt>normal</tt>' label or the
1799'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1800"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1801"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1802href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
1803continued at the dynamically nearest "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1804
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1805<h5>Arguments:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1806
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1807<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1808
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1809<ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1810 <li>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]1811 The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1812 convention</a> the call should use. If none is specified, the call defaults
1813 to using C calling conventions.
1814 </li>
1815 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1816 function value being invoked. In most cases, this is a direct function
1817 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1818 an arbitrary pointer to function value.
1819 </li>
1820
1821 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1822 function to be invoked. </li>
1823
1824 <li>'<tt>function args</tt>': argument list whose types match the function
1825 signature argument types. If the function signature indicates the function
1826 accepts a variable number of arguments, the extra arguments can be
1827 specified. </li>
1828
1829 <li>'<tt>normal label</tt>': the label reached when the called function
1830 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1831
1832 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1833 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1834
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1835</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1836
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1837<h5>Semantics:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1838
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1839<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1840href="#i_call">call</a></tt>' instruction in most regards. The primary
1841difference is that it establishes an association with a label, which is used by
1842the runtime library to unwind the stack.</p>
1843
1844<p>This instruction is used in languages with destructors to ensure that proper
1845cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1846exception. Additionally, this is important for implementation of
1847'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1848
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1849<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1850<pre>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1851 %retval = invoke i32 %Test(i32 15) to label %Continue
1852 unwind label %TestCleanup <i>; {i32}:retval set</i>
1853 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Test(i32 15) to label %Continue
1854 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1855</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1856</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1857
1858
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1859<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1860
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1861<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1862Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1863
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1864<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1865
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1866<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1867<pre>
1868 unwind
1869</pre>
1870
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1871<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1872
1873<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
1874at the first callee in the dynamic call stack which used an <a
1875href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
1876primarily used to implement exception handling.</p>
1877
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1878<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1879
1880<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
1881immediately halt. The dynamic call stack is then searched for the first <a
1882href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
1883execution continues at the "exceptional" destination block specified by the
1884<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
1885dynamic call chain, undefined behavior results.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1886</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1887
1888<!-- _______________________________________________________________________ -->
1889
1890<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
1891Instruction</a> </div>
1892
1893<div class="doc_text">
1894
1895<h5>Syntax:</h5>
1896<pre>
1897 unreachable
1898</pre>
1899
1900<h5>Overview:</h5>
1901
1902<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
1903instruction is used to inform the optimizer that a particular portion of the
1904code is not reachable. This can be used to indicate that the code after a
1905no-return function cannot be reached, and other facts.</p>
1906
1907<h5>Semantics:</h5>
1908
1909<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
1910</div>
1911
1912
1913
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1914<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1915<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1916<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1917<p>Binary operators are used to do most of the computation in a
1918program. They require two operands, execute an operation on them, and
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1919produce a single value. The operands might represent
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1920multiple 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]1921The result value of a binary operator is not
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1922necessarily the same type as its operands.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1923<p>There are several different binary operators:</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1924</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1925<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1926<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
1927Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1928<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1929<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1930<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]1931</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1932<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1933<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1934<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1935<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1936 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1937 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]1938Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1939<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1940<p>The value produced is the integer or floating point sum of the two
1941operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1942<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1943<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]1944</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1945</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1946<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1947<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
1948Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1949<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1950<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1951<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]1952</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1953<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1954<p>The '<tt>sub</tt>' instruction returns the difference of its two
1955operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1956<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
1957instruction present in most other intermediate representations.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1958<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1959<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1960 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1961values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1962This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1963Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1964<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1965<p>The value produced is the integer or floating point difference of
1966the two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1967<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]1968<pre>
1969 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1970 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1971</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1972</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1973<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1974<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
1975Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1976<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1977<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1978<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]1979</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1980<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1981<p>The '<tt>mul</tt>' instruction returns the product of its two
1982operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1983<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1984<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1985 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1986values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1987This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1988Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1989<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1990<p>The value produced is the integer or floating point product of the
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1991two operands.</p>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1992<p>Because the operands are the same width, the result of an integer
1993multiplication is the same whether the operands should be deemed unsigned or
1994signed.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1995<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1996<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]1997</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1998</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1999<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2000<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2001</a></div>
2002<div class="doc_text">
2003<h5>Syntax:</h5>
2004<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2005</pre>
2006<h5>Overview:</h5>
2007<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2008operands.</p>
2009<h5>Arguments:</h5>
2010<p>The two arguments to the '<tt>udiv</tt>' instruction must be
2011<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2012types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2013of the values in which case the elements must be integers.</p>
2014<h5>Semantics:</h5>
2015<p>The value produced is the unsigned integer quotient of the two operands. This
2016instruction always performs an unsigned division operation, regardless of
2017whether the arguments are unsigned or not.</p>
2018<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2019<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]2020</pre>
2021</div>
2022<!-- _______________________________________________________________________ -->
2023<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2024</a> </div>
2025<div class="doc_text">
2026<h5>Syntax:</h5>
2027<pre> &lt;result&gt; = sdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2028</pre>
2029<h5>Overview:</h5>
2030<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2031operands.</p>
2032<h5>Arguments:</h5>
2033<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2034<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2035types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2036of the values in which case the elements must be integers.</p>
2037<h5>Semantics:</h5>
2038<p>The value produced is the signed integer quotient of the two operands. This
2039instruction always performs a signed division operation, regardless of whether
2040the arguments are signed or not.</p>
2041<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2042<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]2043</pre>
2044</div>
2045<!-- _______________________________________________________________________ -->
2046<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2047Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2048<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2049<h5>Syntax:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2050<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]2051</pre>
2052<h5>Overview:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2053<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2054operands.</p>
2055<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2056<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2057<a href="#t_floating">floating point</a> values. Both arguments must have
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2058identical types. This instruction can also take <a href="#t_vector">vector</a>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2059versions of floating point values.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2060<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2061<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2062<h5>Example:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2063<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]2064</pre>
2065</div>
2066<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2067<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2068</div>
2069<div class="doc_text">
2070<h5>Syntax:</h5>
2071<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2072</pre>
2073<h5>Overview:</h5>
2074<p>The '<tt>urem</tt>' instruction returns the remainder from the
2075unsigned division of its two arguments.</p>
2076<h5>Arguments:</h5>
2077<p>The two arguments to the '<tt>urem</tt>' instruction must be
2078<a href="#t_integer">integer</a> values. Both arguments must have identical
2079types.</p>
2080<h5>Semantics:</h5>
2081<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
2082This instruction always performs an unsigned division to get the remainder,
2083regardless of whether the arguments are unsigned or not.</p>
2084<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2085<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]2086</pre>
2087
2088</div>
2089<!-- _______________________________________________________________________ -->
2090<div class="doc_subsubsection"> <a name="i_srem">'<tt>srem</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2091Instruction</a> </div>
2092<div class="doc_text">
2093<h5>Syntax:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2094<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]2095</pre>
2096<h5>Overview:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2097<p>The '<tt>srem</tt>' instruction returns the remainder from the
2098signed division of its two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2099<h5>Arguments:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2100<p>The two arguments to the '<tt>srem</tt>' instruction must be
2101<a href="#t_integer">integer</a> values. Both arguments must have identical
2102types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2103<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2104<p>This instruction returns the <i>remainder</i> of a division (where the result
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2105has the same sign as the dividend, <tt>var1</tt>), not the <i>modulo</i>
2106operator (where the result has the same sign as the divisor, <tt>var2</tt>) of
2107a value. For more information about the difference, see <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2108 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2109Math Forum</a>. For a table of how this is implemented in various languages,
Reid Spencer64f5c6c2007-03-24 22:40:44 +0000[diff] [blame]2110please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2111Wikipedia: modulo operation</a>.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2112<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2113<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]2114</pre>
2115
2116</div>
2117<!-- _______________________________________________________________________ -->
2118<div class="doc_subsubsection"> <a name="i_frem">'<tt>frem</tt>'
2119Instruction</a> </div>
2120<div class="doc_text">
2121<h5>Syntax:</h5>
2122<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2123</pre>
2124<h5>Overview:</h5>
2125<p>The '<tt>frem</tt>' instruction returns the remainder from the
2126division of its two operands.</p>
2127<h5>Arguments:</h5>
2128<p>The two arguments to the '<tt>frem</tt>' instruction must be
2129<a href="#t_floating">floating point</a> values. Both arguments must have
2130identical types.</p>
2131<h5>Semantics:</h5>
2132<p>This instruction returns the <i>remainder</i> of a division.</p>
2133<h5>Example:</h5>
2134<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]2135</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2136</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]2137
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]2138<!-- ======================================================================= -->
2139<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2140Operations</a> </div>
2141<div class="doc_text">
2142<p>Bitwise binary operators are used to do various forms of
2143bit-twiddling in a program. They are generally very efficient
2144instructions and can commonly be strength reduced from other
2145instructions. They require two operands, execute an operation on them,
2146and produce a single value. The resulting value of the bitwise binary
2147operators is always the same type as its first operand.</p>
2148</div>
2149
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2150<!-- _______________________________________________________________________ -->
2151<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2152Instruction</a> </div>
2153<div class="doc_text">
2154<h5>Syntax:</h5>
2155<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2156</pre>
2157<h5>Overview:</h5>
2158<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2159the left a specified number of bits.</p>
2160<h5>Arguments:</h5>
2161<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
2162 href="#t_integer">integer</a> type.</p>
2163<h5>Semantics:</h5>
2164<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>.</p>
2165<h5>Example:</h5><pre>
2166 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2167 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2168 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
2169</pre>
2170</div>
2171<!-- _______________________________________________________________________ -->
2172<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2173Instruction</a> </div>
2174<div class="doc_text">
2175<h5>Syntax:</h5>
2176<pre> &lt;result&gt; = lshr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2177</pre>
2178
2179<h5>Overview:</h5>
2180<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2181operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2182
2183<h5>Arguments:</h5>
2184<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
2185<a href="#t_integer">integer</a> type.</p>
2186
2187<h5>Semantics:</h5>
2188<p>This instruction always performs a logical shift right operation. The most
2189significant bits of the result will be filled with zero bits after the
2190shift.</p>
2191
2192<h5>Example:</h5>
2193<pre>
2194 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2195 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2196 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2197 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
2198</pre>
2199</div>
2200
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]2201<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2202<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2203Instruction</a> </div>
2204<div class="doc_text">
2205
2206<h5>Syntax:</h5>
2207<pre> &lt;result&gt; = ashr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2208</pre>
2209
2210<h5>Overview:</h5>
2211<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2212operand shifted to the right a specified number of bits with sign extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2213
2214<h5>Arguments:</h5>
2215<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
2216<a href="#t_integer">integer</a> type.</p>
2217
2218<h5>Semantics:</h5>
2219<p>This instruction always performs an arithmetic shift right operation,
2220The most significant bits of the result will be filled with the sign bit
2221of <tt>var1</tt>.</p>
2222
2223<h5>Example:</h5>
2224<pre>
2225 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2226 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2227 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2228 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
2229</pre>
2230</div>
2231
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2232<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2233<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2234Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2235<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2236<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2237<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]2238</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2239<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2240<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2241its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2242<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2243<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2244 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2245identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2246<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2247<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2248<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2249<div style="align: center">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2250<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2251 <tbody>
2252 <tr>
2253 <td>In0</td>
2254 <td>In1</td>
2255 <td>Out</td>
2256 </tr>
2257 <tr>
2258 <td>0</td>
2259 <td>0</td>
2260 <td>0</td>
2261 </tr>
2262 <tr>
2263 <td>0</td>
2264 <td>1</td>
2265 <td>0</td>
2266 </tr>
2267 <tr>
2268 <td>1</td>
2269 <td>0</td>
2270 <td>0</td>
2271 </tr>
2272 <tr>
2273 <td>1</td>
2274 <td>1</td>
2275 <td>1</td>
2276 </tr>
2277 </tbody>
2278</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2279</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2280<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2281<pre> &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
2282 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2283 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2284</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2285</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2286<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2287<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2288<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2289<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2290<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]2291</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2292<h5>Overview:</h5>
2293<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2294or of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2295<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2296<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2297 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2298identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2299<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2300<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2301<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2302<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2303<table border="1" cellspacing="0" cellpadding="4">
2304 <tbody>
2305 <tr>
2306 <td>In0</td>
2307 <td>In1</td>
2308 <td>Out</td>
2309 </tr>
2310 <tr>
2311 <td>0</td>
2312 <td>0</td>
2313 <td>0</td>
2314 </tr>
2315 <tr>
2316 <td>0</td>
2317 <td>1</td>
2318 <td>1</td>
2319 </tr>
2320 <tr>
2321 <td>1</td>
2322 <td>0</td>
2323 <td>1</td>
2324 </tr>
2325 <tr>
2326 <td>1</td>
2327 <td>1</td>
2328 <td>1</td>
2329 </tr>
2330 </tbody>
2331</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2332</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2333<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2334<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2335 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2336 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2337</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2338</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2339<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2340<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2341Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2342<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2343<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2344<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]2345</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2346<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2347<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2348or of its two operands. The <tt>xor</tt> is used to implement the
2349"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2350<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2351<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2352 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2353identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2354<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2355<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2356<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2357<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2358<table border="1" cellspacing="0" cellpadding="4">
2359 <tbody>
2360 <tr>
2361 <td>In0</td>
2362 <td>In1</td>
2363 <td>Out</td>
2364 </tr>
2365 <tr>
2366 <td>0</td>
2367 <td>0</td>
2368 <td>0</td>
2369 </tr>
2370 <tr>
2371 <td>0</td>
2372 <td>1</td>
2373 <td>1</td>
2374 </tr>
2375 <tr>
2376 <td>1</td>
2377 <td>0</td>
2378 <td>1</td>
2379 </tr>
2380 <tr>
2381 <td>1</td>
2382 <td>1</td>
2383 <td>0</td>
2384 </tr>
2385 </tbody>
2386</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2387</div>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2388<p> </p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2389<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2390<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2391 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2392 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2393 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2394</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2395</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2396
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2397<!-- ======================================================================= -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2398<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2399 <a name="vectorops">Vector Operations</a>
2400</div>
2401
2402<div class="doc_text">
2403
2404<p>LLVM supports several instructions to represent vector operations in a
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2405target-independent manner. These instructions cover the element-access and
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2406vector-specific operations needed to process vectors effectively. While LLVM
2407does directly support these vector operations, many sophisticated algorithms
2408will want to use target-specific intrinsics to take full advantage of a specific
2409target.</p>
2410
2411</div>
2412
2413<!-- _______________________________________________________________________ -->
2414<div class="doc_subsubsection">
2415 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2416</div>
2417
2418<div class="doc_text">
2419
2420<h5>Syntax:</h5>
2421
2422<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2423 &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]2424</pre>
2425
2426<h5>Overview:</h5>
2427
2428<p>
2429The '<tt>extractelement</tt>' instruction extracts a single scalar
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2430element from a vector at a specified index.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2431</p>
2432
2433
2434<h5>Arguments:</h5>
2435
2436<p>
2437The first operand of an '<tt>extractelement</tt>' instruction is a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2438value of <a href="#t_vector">vector</a> type. The second operand is
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2439an index indicating the position from which to extract the element.
2440The index may be a variable.</p>
2441
2442<h5>Semantics:</h5>
2443
2444<p>
2445The result is a scalar of the same type as the element type of
2446<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2447<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2448results are undefined.
2449</p>
2450
2451<h5>Example:</h5>
2452
2453<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2454 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2455</pre>
2456</div>
2457
2458
2459<!-- _______________________________________________________________________ -->
2460<div class="doc_subsubsection">
2461 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2462</div>
2463
2464<div class="doc_text">
2465
2466<h5>Syntax:</h5>
2467
2468<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2469 &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]2470</pre>
2471
2472<h5>Overview:</h5>
2473
2474<p>
2475The '<tt>insertelement</tt>' instruction inserts a scalar
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2476element into a vector at a specified index.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2477</p>
2478
2479
2480<h5>Arguments:</h5>
2481
2482<p>
2483The first operand of an '<tt>insertelement</tt>' instruction is a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2484value of <a href="#t_vector">vector</a> type. The second operand is a
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2485scalar value whose type must equal the element type of the first
2486operand. The third operand is an index indicating the position at
2487which to insert the value. The index may be a variable.</p>
2488
2489<h5>Semantics:</h5>
2490
2491<p>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2492The result is a vector of the same type as <tt>val</tt>. Its
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2493element values are those of <tt>val</tt> except at position
2494<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2495exceeds the length of <tt>val</tt>, the results are undefined.
2496</p>
2497
2498<h5>Example:</h5>
2499
2500<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2501 %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]2502</pre>
2503</div>
2504
2505<!-- _______________________________________________________________________ -->
2506<div class="doc_subsubsection">
2507 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2508</div>
2509
2510<div class="doc_text">
2511
2512<h5>Syntax:</h5>
2513
2514<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2515 &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]2516</pre>
2517
2518<h5>Overview:</h5>
2519
2520<p>
2521The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2522from two input vectors, returning a vector of the same type.
2523</p>
2524
2525<h5>Arguments:</h5>
2526
2527<p>
2528The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2529with types that match each other and types that match the result of the
2530instruction. The third argument is a shuffle mask, which has the same number
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2531of elements as the other vector type, but whose element type is always 'i32'.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2532</p>
2533
2534<p>
2535The shuffle mask operand is required to be a constant vector with either
2536constant integer or undef values.
2537</p>
2538
2539<h5>Semantics:</h5>
2540
2541<p>
2542The elements of the two input vectors are numbered from left to right across
2543both of the vectors. The shuffle mask operand specifies, for each element of
2544the result vector, which element of the two input registers the result element
2545gets. The element selector may be undef (meaning "don't care") and the second
2546operand may be undef if performing a shuffle from only one vector.
2547</p>
2548
2549<h5>Example:</h5>
2550
2551<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2552 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2553 &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]2554 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2555 &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]2556</pre>
2557</div>
2558
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]2559
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2560<!-- ======================================================================= -->
2561<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2562 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2563</div>
2564
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2565<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2566
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2567<p>A key design point of an SSA-based representation is how it
2568represents memory. In LLVM, no memory locations are in SSA form, which
2569makes things very simple. This section describes how to read, write,
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2570allocate, and free memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2571
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2572</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2573
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2574<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2575<div class="doc_subsubsection">
2576 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2577</div>
2578
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2579<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2580
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2581<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2582
2583<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2584 &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]2585</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2586
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2587<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2588
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2589<p>The '<tt>malloc</tt>' instruction allocates memory from the system
2590heap and returns a pointer to it.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2591
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2592<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2593
2594<p>The '<tt>malloc</tt>' instruction allocates
2595<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswell6e4ca612004-02-24 16:13:56 +0000[diff] [blame]2596bytes of memory from the operating system and returns a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2597appropriate type to the program. If "NumElements" is specified, it is the
2598number of elements allocated. If an alignment is specified, the value result
2599of the allocation is guaranteed to be aligned to at least that boundary. If
2600not specified, or if zero, the target can choose to align the allocation on any
2601convenient boundary.</p>
2602
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2603<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2604
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2605<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2606
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2607<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
2608a pointer is returned.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2609
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2610<h5>Example:</h5>
2611
2612<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2613 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2614
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]2615 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
2616 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
2617 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
2618 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
2619 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2620</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2621</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2622
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2623<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2624<div class="doc_subsubsection">
2625 <a name="i_free">'<tt>free</tt>' Instruction</a>
2626</div>
2627
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2628<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2629
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2630<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2631
2632<pre>
2633 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2634</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2635
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2636<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2637
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2638<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2639memory heap to be reallocated in the future.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2640
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2641<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2642
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2643<p>'<tt>value</tt>' shall be a pointer value that points to a value
2644that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
2645instruction.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2646
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2647<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2648
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2649<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2650after this instruction executes.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2651
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2652<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2653
2654<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2655 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
2656 free [4 x i8]* %array
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2657</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2658</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2659
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2660<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2661<div class="doc_subsubsection">
2662 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
2663</div>
2664
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2665<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2666
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2667<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2668
2669<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2670 &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]2671</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2672
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2673<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2674
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2675<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
2676currently executing function, to be automatically released when this function
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2677returns to its caller.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2678
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2679<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2680
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2681<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2682bytes of memory on the runtime stack, returning a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2683appropriate type to the program. If "NumElements" is specified, it is the
2684number of elements allocated. If an alignment is specified, the value result
2685of the allocation is guaranteed to be aligned to at least that boundary. If
2686not specified, or if zero, the target can choose to align the allocation on any
2687convenient boundary.</p>
2688
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2689<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2690
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2691<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2692
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2693<p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2694memory is automatically released when the function returns. The '<tt>alloca</tt>'
2695instruction is commonly used to represent automatic variables that must
2696have an address available. When the function returns (either with the <tt><a
John Criswelldae2e932005-05-12 16:55:34 +0000[diff] [blame]2697 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]2698instructions), the memory is reclaimed.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2699
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2700<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2701
2702<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2703 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2704 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
2705 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2706 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2707</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2708</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2709
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2710<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2711<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
2712Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2713<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2714<h5>Syntax:</h5>
Christopher Lamb2330e4d2007-04-21 08:16:25 +0000[diff] [blame]2715<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]2716<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2717<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2718<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2719<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2720address from which to load. The pointer must point to a <a
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]2721 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2722marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2723the number or order of execution of this <tt>load</tt> with other
2724volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
2725instructions. </p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2726<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2727<p>The location of memory pointed to is loaded.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2728<h5>Examples:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2729<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2730 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2731 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2732 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2733</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2734</div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2735<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2736<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
2737Instruction</a> </div>
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]2738<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2739<h5>Syntax:</h5>
Christopher Lamb2330e4d2007-04-21 08:16:25 +0000[diff] [blame]2740<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
2741 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]2742</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2743<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2744<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2745<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2746<p>There are two arguments to the '<tt>store</tt>' instruction: a value
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2747to 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]2748operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2749operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2750optimizer is not allowed to modify the number or order of execution of
2751this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
2752 href="#i_store">store</a></tt> instructions.</p>
2753<h5>Semantics:</h5>
2754<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
2755at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2756<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2757<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2758 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2759 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2760 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2761</pre>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2762</div>
2763
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2764<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2765<div class="doc_subsubsection">
2766 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
2767</div>
2768
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2769<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2770<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2771<pre>
2772 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
2773</pre>
2774
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2775<h5>Overview:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2776
2777<p>
2778The '<tt>getelementptr</tt>' instruction is used to get the address of a
2779subelement of an aggregate data structure.</p>
2780
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2781<h5>Arguments:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2782
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2783<p>This instruction takes a list of integer operands that indicate what
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2784elements of the aggregate object to index to. The actual types of the arguments
2785provided depend on the type of the first pointer argument. The
2786'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2787levels 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]2788structure, only <tt>i32</tt> integer constants are allowed. When indexing
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2789into an array or pointer, only integers of 32 or 64 bits are allowed, and will
2790be sign extended to 64-bit values.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2791
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2792<p>For example, let's consider a C code fragment and how it gets
2793compiled to LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2794
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2795<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2796<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2797struct RT {
2798 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]2799 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2800 char C;
2801};
2802struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]2803 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2804 double Y;
2805 struct RT Z;
2806};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2807
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]2808int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2809 return &amp;s[1].Z.B[5][13];
2810}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2811</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2812</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2813
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2814<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2815
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2816<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2817<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2818%RT = type { i8 , [10 x [20 x i32]], i8 }
2819%ST = type { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2820
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2821define i32* %foo(%ST* %s) {
2822entry:
2823 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
2824 ret i32* %reg
2825}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2826</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2827</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2828
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2829<h5>Semantics:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2830
2831<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2832on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2833and <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]2834<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]2835to 64-bits. <a href="#t_struct">Structure</a> types require <tt>i32</tt>
Reid Spencer42ddd842006-12-03 16:53:48 +0000[diff] [blame]2836<b>constants</b>.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2837
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2838<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]2839type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2840}</tt>' type, a structure. The second index indexes into the third element of
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2841the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
2842i8 }</tt>' type, another structure. The third index indexes into the second
2843element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2844array. The two dimensions of the array are subscripted into, yielding an
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2845'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
2846to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2847
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2848<p>Note that it is perfectly legal to index partially through a
2849structure, returning a pointer to an inner element. Because of this,
2850the LLVM code for the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2851
2852<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2853 define i32* %foo(%ST* %s) {
2854 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2855 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
2856 %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]2857 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
2858 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
2859 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2860 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2861</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2862
2863<p>Note that it is undefined to access an array out of bounds: array and
2864pointer indexes must always be within the defined bounds of the array type.
2865The one exception for this rules is zero length arrays. These arrays are
2866defined to be accessible as variable length arrays, which requires access
2867beyond the zero'th element.</p>
2868
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2869<p>The getelementptr instruction is often confusing. For some more insight
2870into how it works, see <a href="GetElementPtr.html">the getelementptr
2871FAQ</a>.</p>
2872
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2873<h5>Example:</h5>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2874
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2875<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2876 <i>; yields [12 x i8]*:aptr</i>
2877 %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2878</pre>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2879</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2880
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2881<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]2882<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2883</div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2884<div class="doc_text">
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]2885<p>The instructions in this category are the conversion instructions (casting)
2886which all take a single operand and a type. They perform various bit conversions
2887on the operand.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2888</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2889
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2890<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2891<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2892 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
2893</div>
2894<div class="doc_text">
2895
2896<h5>Syntax:</h5>
2897<pre>
2898 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2899</pre>
2900
2901<h5>Overview:</h5>
2902<p>
2903The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
2904</p>
2905
2906<h5>Arguments:</h5>
2907<p>
2908The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
2909be 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]2910and type of the result, which must be an <a href="#t_integer">integer</a>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2911type. The bit size of <tt>value</tt> must be larger than the bit size of
2912<tt>ty2</tt>. Equal sized types are not allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2913
2914<h5>Semantics:</h5>
2915<p>
2916The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2917and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
2918larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
2919It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2920
2921<h5>Example:</h5>
2922<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2923 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2924 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
2925 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2926</pre>
2927</div>
2928
2929<!-- _______________________________________________________________________ -->
2930<div class="doc_subsubsection">
2931 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
2932</div>
2933<div class="doc_text">
2934
2935<h5>Syntax:</h5>
2936<pre>
2937 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2938</pre>
2939
2940<h5>Overview:</h5>
2941<p>The '<tt>zext</tt>' instruction zero extends its operand to type
2942<tt>ty2</tt>.</p>
2943
2944
2945<h5>Arguments:</h5>
2946<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]2947<a href="#t_integer">integer</a> type, and a type to cast it to, which must
2948also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2949<tt>value</tt> must be smaller than the bit size of the destination type,
2950<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2951
2952<h5>Semantics:</h5>
2953<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
Chris Lattnerd1d25172007-05-24 19:13:27 +0000[diff] [blame]2954bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2955
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]2956<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]2957
2958<h5>Example:</h5>
2959<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2960 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2961 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2962</pre>
2963</div>
2964
2965<!-- _______________________________________________________________________ -->
2966<div class="doc_subsubsection">
2967 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
2968</div>
2969<div class="doc_text">
2970
2971<h5>Syntax:</h5>
2972<pre>
2973 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2974</pre>
2975
2976<h5>Overview:</h5>
2977<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
2978
2979<h5>Arguments:</h5>
2980<p>
2981The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2982<a href="#t_integer">integer</a> type, and a type to cast it to, which must
2983also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2984<tt>value</tt> must be smaller than the bit size of the destination type,
2985<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2986
2987<h5>Semantics:</h5>
2988<p>
2989The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
2990bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
Chris Lattnerd1d25172007-05-24 19:13:27 +0000[diff] [blame]2991the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2992
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2993<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]2994
2995<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2996<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2997 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2998 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2999</pre>
3000</div>
3001
3002<!-- _______________________________________________________________________ -->
3003<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]3004 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3005</div>
3006
3007<div class="doc_text">
3008
3009<h5>Syntax:</h5>
3010
3011<pre>
3012 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3013</pre>
3014
3015<h5>Overview:</h5>
3016<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3017<tt>ty2</tt>.</p>
3018
3019
3020<h5>Arguments:</h5>
3021<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
3022 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
3023cast it to. The size of <tt>value</tt> must be larger than the size of
3024<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
3025<i>no-op cast</i>.</p>
3026
3027<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3028<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
3029<a href="#t_floating">floating point</a> type to a smaller
3030<a href="#t_floating">floating point</a> type. If the value cannot fit within
3031the destination type, <tt>ty2</tt>, then the results are undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]3032
3033<h5>Example:</h5>
3034<pre>
3035 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
3036 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
3037</pre>
3038</div>
3039
3040<!-- _______________________________________________________________________ -->
3041<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3042 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3043</div>
3044<div class="doc_text">
3045
3046<h5>Syntax:</h5>
3047<pre>
3048 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3049</pre>
3050
3051<h5>Overview:</h5>
3052<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3053floating point value.</p>
3054
3055<h5>Arguments:</h5>
3056<p>The '<tt>fpext</tt>' instruction takes a
3057<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3058and a <a href="#t_floating">floating point</a> type to cast it to. The source
3059type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3060
3061<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3062<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3063<a href="#t_floating">floating point</a> type to a larger
3064<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3065used to make a <i>no-op cast</i> because it always changes bits. Use
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3066<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]3067
3068<h5>Example:</h5>
3069<pre>
3070 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3071 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3072</pre>
3073</div>
3074
3075<!-- _______________________________________________________________________ -->
3076<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]3077 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3078</div>
3079<div class="doc_text">
3080
3081<h5>Syntax:</h5>
3082<pre>
3083 &lt;result&gt; = fp2uint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3084</pre>
3085
3086<h5>Overview:</h5>
3087<p>The '<tt>fp2uint</tt>' converts a floating point <tt>value</tt> to its
3088unsigned integer equivalent of type <tt>ty2</tt>.
3089</p>
3090
3091<h5>Arguments:</h5>
3092<p>The '<tt>fp2uint</tt>' instruction takes a value to cast, which must be a
3093<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]3094must be an <a href="#t_integer">integer</a> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3095
3096<h5>Semantics:</h5>
3097<p> The '<tt>fp2uint</tt>' instruction converts its
3098<a href="#t_floating">floating point</a> operand into the nearest (rounding
3099towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3100the results are undefined.</p>
3101
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3102<p>When converting to i1, the conversion is done as a comparison against
3103zero. If the <tt>value</tt> was zero, the i1 result will be <tt>false</tt>.
3104If 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]3105
3106<h5>Example:</h5>
3107<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3108 %X = fp2uint double 123.0 to i32 <i>; yields i32:123</i>
3109 %Y = fp2uint float 1.0E+300 to i1 <i>; yields i1:true</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3110 %X = fp2uint float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3111</pre>
3112</div>
3113
3114<!-- _______________________________________________________________________ -->
3115<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3116 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3117</div>
3118<div class="doc_text">
3119
3120<h5>Syntax:</h5>
3121<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3122 &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]3123</pre>
3124
3125<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3126<p>The '<tt>fptosi</tt>' instruction converts
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3127<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]3128</p>
3129
3130
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3131<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3132<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]3133<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]3134must also be an <a href="#t_integer">integer</a> type.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3135
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3136<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3137<p>The '<tt>fptosi</tt>' instruction converts its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3138<a href="#t_floating">floating point</a> operand into the nearest (rounding
3139towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3140the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3141
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3142<p>When converting to i1, the conversion is done as a comparison against
3143zero. If the <tt>value</tt> was zero, the i1 result will be <tt>false</tt>.
3144If 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]3145
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3146<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3147<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3148 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
3149 %Y = fptosi float 1.0E-247 to i1 <i>; yields i1:true</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3150 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3151</pre>
3152</div>
3153
3154<!-- _______________________________________________________________________ -->
3155<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3156 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3157</div>
3158<div class="doc_text">
3159
3160<h5>Syntax:</h5>
3161<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3162 &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]3163</pre>
3164
3165<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3166<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3167integer and converts that value to the <tt>ty2</tt> type.</p>
3168
3169
3170<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3171<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]3172<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]3173be a <a href="#t_floating">floating point</a> type.</p>
3174
3175<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3176<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3177integer quantity and converts it to the corresponding floating point value. If
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]3178the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3179
3180
3181<h5>Example:</h5>
3182<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3183 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3184 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3185</pre>
3186</div>
3187
3188<!-- _______________________________________________________________________ -->
3189<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3190 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3191</div>
3192<div class="doc_text">
3193
3194<h5>Syntax:</h5>
3195<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3196 &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]3197</pre>
3198
3199<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3200<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3201integer and converts that value to the <tt>ty2</tt> type.</p>
3202
3203<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3204<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]3205<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]3206a <a href="#t_floating">floating point</a> type.</p>
3207
3208<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3209<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3210integer quantity and converts it to the corresponding floating point value. If
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]3211the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3212
3213<h5>Example:</h5>
3214<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3215 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3216 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3217</pre>
3218</div>
3219
3220<!-- _______________________________________________________________________ -->
3221<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3222 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3223</div>
3224<div class="doc_text">
3225
3226<h5>Syntax:</h5>
3227<pre>
3228 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3229</pre>
3230
3231<h5>Overview:</h5>
3232<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3233the integer type <tt>ty2</tt>.</p>
3234
3235<h5>Arguments:</h5>
3236<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3237must 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]3238<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
3239
3240<h5>Semantics:</h5>
3241<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3242<tt>ty2</tt> by interpreting the pointer value as an integer and either
3243truncating or zero extending that value to the size of the integer type. If
3244<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3245<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]3246are the same size, then nothing is done (<i>no-op cast</i>) other than a type
3247change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3248
3249<h5>Example:</h5>
3250<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3251 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
3252 %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]3253</pre>
3254</div>
3255
3256<!-- _______________________________________________________________________ -->
3257<div class="doc_subsubsection">
3258 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3259</div>
3260<div class="doc_text">
3261
3262<h5>Syntax:</h5>
3263<pre>
3264 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3265</pre>
3266
3267<h5>Overview:</h5>
3268<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3269a pointer type, <tt>ty2</tt>.</p>
3270
3271<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3272<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3273value to cast, and a type to cast it to, which must be a
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]3274<a href="#t_pointer">pointer</a> type.
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3275
3276<h5>Semantics:</h5>
3277<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3278<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3279the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3280size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3281the size of a pointer then a zero extension is done. If they are the same size,
3282nothing is done (<i>no-op cast</i>).</p>
3283
3284<h5>Example:</h5>
3285<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3286 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
3287 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
3288 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3289</pre>
3290</div>
3291
3292<!-- _______________________________________________________________________ -->
3293<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3294 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3295</div>
3296<div class="doc_text">
3297
3298<h5>Syntax:</h5>
3299<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3300 &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]3301</pre>
3302
3303<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3304<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3305<tt>ty2</tt> without changing any bits.</p>
3306
3307<h5>Arguments:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3308<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3309a first class value, and a type to cast it to, which must also be a <a
3310 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
Reid Spencer19b569f2007-01-09 20:08:58 +0000[diff] [blame]3311and the destination type, <tt>ty2</tt>, must be identical. If the source
3312type is a pointer, the destination type must also be a pointer.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3313
3314<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3315<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3316<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3317this conversion. The conversion is done as if the <tt>value</tt> had been
3318stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3319converted to other pointer types with this instruction. To convert pointers to
3320other types, use the <a href="#i_inttoptr">inttoptr</a> or
3321<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3322
3323<h5>Example:</h5>
3324<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3325 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3326 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
3327 %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3328</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3329</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3330
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3331<!-- ======================================================================= -->
3332<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3333<div class="doc_text">
3334<p>The instructions in this category are the "miscellaneous"
3335instructions, which defy better classification.</p>
3336</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3337
3338<!-- _______________________________________________________________________ -->
3339<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3340</div>
3341<div class="doc_text">
3342<h5>Syntax:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3343<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]3344</pre>
3345<h5>Overview:</h5>
3346<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
3347of its two integer operands.</p>
3348<h5>Arguments:</h5>
3349<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3350the condition code indicating the kind of comparison to perform. It is not
3351a value, just a keyword. The possible condition code are:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3352<ol>
3353 <li><tt>eq</tt>: equal</li>
3354 <li><tt>ne</tt>: not equal </li>
3355 <li><tt>ugt</tt>: unsigned greater than</li>
3356 <li><tt>uge</tt>: unsigned greater or equal</li>
3357 <li><tt>ult</tt>: unsigned less than</li>
3358 <li><tt>ule</tt>: unsigned less or equal</li>
3359 <li><tt>sgt</tt>: signed greater than</li>
3360 <li><tt>sge</tt>: signed greater or equal</li>
3361 <li><tt>slt</tt>: signed less than</li>
3362 <li><tt>sle</tt>: signed less or equal</li>
3363</ol>
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3364<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3365<a href="#t_pointer">pointer</a> typed. They must also be identical types.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3366<h5>Semantics:</h5>
3367<p>The '<tt>icmp</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>eq</tt>: yields <tt>true</tt> if the operands are equal,
3372 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3373 </li>
3374 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3375 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3376 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3377 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3378 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3379 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3380 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3381 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3382 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3383 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3384 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3385 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3386 <li><tt>sge</tt>: interprets the operands as signed values and yields
3387 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3388 <li><tt>slt</tt>: interprets the operands as signed values and yields
3389 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3390 <li><tt>sle</tt>: interprets the operands as signed values and yields
3391 <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]3392</ol>
3393<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3394values are compared as if they were integers.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3395
3396<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3397<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3398 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3399 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3400 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3401 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3402 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3403</pre>
3404</div>
3405
3406<!-- _______________________________________________________________________ -->
3407<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3408</div>
3409<div class="doc_text">
3410<h5>Syntax:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3411<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]3412</pre>
3413<h5>Overview:</h5>
3414<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3415of its floating point operands.</p>
3416<h5>Arguments:</h5>
3417<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3418the condition code indicating the kind of comparison to perform. It is not
3419a value, just a keyword. The possible condition code are:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3420<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3421 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3422 <li><tt>oeq</tt>: ordered and equal</li>
3423 <li><tt>ogt</tt>: ordered and greater than </li>
3424 <li><tt>oge</tt>: ordered and greater than or equal</li>
3425 <li><tt>olt</tt>: ordered and less than </li>
3426 <li><tt>ole</tt>: ordered and less than or equal</li>
3427 <li><tt>one</tt>: ordered and not equal</li>
3428 <li><tt>ord</tt>: ordered (no nans)</li>
3429 <li><tt>ueq</tt>: unordered or equal</li>
3430 <li><tt>ugt</tt>: unordered or greater than </li>
3431 <li><tt>uge</tt>: unordered or greater than or equal</li>
3432 <li><tt>ult</tt>: unordered or less than </li>
3433 <li><tt>ule</tt>: unordered or less than or equal</li>
3434 <li><tt>une</tt>: unordered or not equal</li>
3435 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3436 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3437</ol>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3438<p><i>Ordered</i> means that neither operand is a QNAN while
Reid Spencer93a49852006-12-06 07:08:07 +0000[diff] [blame]3439<i>unordered</i> means that either operand may be a QNAN.</p>
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3440<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be
3441<a href="#t_floating">floating point</a> typed. They must have identical
3442types.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3443<h5>Semantics:</h5>
3444<p>The '<tt>fcmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3445the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3446yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3447<ol>
3448 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3449 <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]3450 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3451 <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]3452 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3453 <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]3454 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3455 <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]3456 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3457 <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]3458 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3459 <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]3460 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3461 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3462 <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]3463 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3464 <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]3465 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3466 <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]3467 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3468 <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]3469 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3470 <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]3471 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3472 <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]3473 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3474 <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]3475 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3476</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3477
3478<h5>Example:</h5>
3479<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3480 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3481 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3482 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3483</pre>
3484</div>
3485
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3486<!-- _______________________________________________________________________ -->
3487<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
3488Instruction</a> </div>
3489<div class="doc_text">
3490<h5>Syntax:</h5>
3491<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
3492<h5>Overview:</h5>
3493<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
3494the SSA graph representing the function.</p>
3495<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3496<p>The type of the incoming values is specified with the first type
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3497field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
3498as arguments, with one pair for each predecessor basic block of the
3499current block. Only values of <a href="#t_firstclass">first class</a>
3500type may be used as the value arguments to the PHI node. Only labels
3501may be used as the label arguments.</p>
3502<p>There must be no non-phi instructions between the start of a basic
3503block and the PHI instructions: i.e. PHI instructions must be first in
3504a basic block.</p>
3505<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3506<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
3507specified by the pair corresponding to the predecessor basic block that executed
3508just prior to the current block.</p>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3509<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3510<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]3511</div>
3512
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3513<!-- _______________________________________________________________________ -->
3514<div class="doc_subsubsection">
3515 <a name="i_select">'<tt>select</tt>' Instruction</a>
3516</div>
3517
3518<div class="doc_text">
3519
3520<h5>Syntax:</h5>
3521
3522<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3523 &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]3524</pre>
3525
3526<h5>Overview:</h5>
3527
3528<p>
3529The '<tt>select</tt>' instruction is used to choose one value based on a
3530condition, without branching.
3531</p>
3532
3533
3534<h5>Arguments:</h5>
3535
3536<p>
3537The '<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.
3538</p>
3539
3540<h5>Semantics:</h5>
3541
3542<p>
3543If the boolean condition evaluates to true, the instruction returns the first
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3544value argument; otherwise, it returns the second value argument.
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3545</p>
3546
3547<h5>Example:</h5>
3548
3549<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3550 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3551</pre>
3552</div>
3553
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]3554
3555<!-- _______________________________________________________________________ -->
3556<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3557 <a name="i_call">'<tt>call</tt>' Instruction</a>
3558</div>
3559
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3560<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3561
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3562<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3563<pre>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3564 &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]3565</pre>
3566
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3567<h5>Overview:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3568
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3569<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3570
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3571<h5>Arguments:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3572
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3573<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3574
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3575<ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3576 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3577 <p>The optional "tail" marker indicates whether the callee function accesses
3578 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3579 function call is eligible for tail call optimization. Note that calls may
3580 be marked "tail" even if they do not occur before a <a
3581 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3582 </li>
3583 <li>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3584 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3585 convention</a> the call should use. If none is specified, the call defaults
3586 to using C calling conventions.
3587 </li>
3588 <li>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3589 <p>'<tt>ty</tt>': shall be the signature of the pointer to function value
3590 being invoked. The argument types must match the types implied by this
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3591 signature. This type can be omitted if the function is not varargs and
3592 if the function type does not return a pointer to a function.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3593 </li>
3594 <li>
3595 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
3596 be invoked. In most cases, this is a direct function invocation, but
3597 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3598 to function value.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3599 </li>
3600 <li>
3601 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencera7e302a2005-05-01 22:22:57 +0000[diff] [blame]3602 function signature argument types. All arguments must be of
3603 <a href="#t_firstclass">first class</a> type. If the function signature
3604 indicates the function accepts a variable number of arguments, the extra
3605 arguments can be specified.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3606 </li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3607</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3608
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3609<h5>Semantics:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3610
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3611<p>The '<tt>call</tt>' instruction is used to cause control flow to
3612transfer to a specified function, with its incoming arguments bound to
3613the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
3614instruction in the called function, control flow continues with the
3615instruction after the function call, and the return value of the
3616function is bound to the result argument. This is a simpler case of
3617the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3618
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3619<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3620
3621<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3622 %retval = call i32 %test(i32 %argc)
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3623 call i32(i8 *, ...) *%printf(i8 * %msg, i32 12, i8 42);
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3624 %X = tail call i32 %foo()
3625 %Y = tail call <a href="#callingconv">fastcc</a> i32 %foo()
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3626</pre>
3627
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3628</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3629
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3630<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3631<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3632 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3633</div>
3634
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3635<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3636
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3637<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3638
3639<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3640 &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]3641</pre>
3642
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3643<h5>Overview:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3644
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3645<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3646the "variable argument" area of a function call. It is used to implement the
3647<tt>va_arg</tt> macro in C.</p>
3648
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3649<h5>Arguments:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3650
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3651<p>This instruction takes a <tt>va_list*</tt> value and the type of
3652the argument. It returns a value of the specified argument type and
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3653increments the <tt>va_list</tt> to point to the next argument. The
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3654actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3655
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3656<h5>Semantics:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3657
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3658<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
3659type from the specified <tt>va_list</tt> and causes the
3660<tt>va_list</tt> to point to the next argument. For more information,
3661see the variable argument handling <a href="#int_varargs">Intrinsic
3662Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3663
3664<p>It is legal for this instruction to be called in a function which does not
3665take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3666function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3667
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3668<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3669href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3670argument.</p>
3671
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3672<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3673
3674<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
3675
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3676</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3677
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3678<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3679<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
3680<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3681
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3682<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3683
3684<p>LLVM supports the notion of an "intrinsic function". These functions have
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]3685well known names and semantics and are required to follow certain restrictions.
3686Overall, these intrinsics represent an extension mechanism for the LLVM
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3687language that does not require changing all of the transformations in LLVM when
Gabor Greif04367bf2007-07-06 22:07:22 +0000[diff] [blame]3688adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3689
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3690<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3691prefix is reserved in LLVM for intrinsic names; thus, function names may not
3692begin with this prefix. Intrinsic functions must always be external functions:
3693you cannot define the body of intrinsic functions. Intrinsic functions may
3694only be used in call or invoke instructions: it is illegal to take the address
3695of an intrinsic function. Additionally, because intrinsic functions are part
3696of the LLVM language, it is required if any are added that they be documented
3697here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3698
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3699<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]3700a family of functions that perform the same operation but on different data
3701types. This is most frequent with the integer types. Since LLVM can represent
3702over 8 million different integer types, there is a way to declare an intrinsic
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3703that can be overloaded based on its arguments. Such an intrinsic will have the
3704names of its argument types encoded into its function name, each
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]3705preceded by a period. For example, the <tt>llvm.ctpop</tt> function can take an
3706integer of any width. This leads to a family of functions such as
3707<tt>i32 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i32 @llvm.ctpop.i29(i29 %val)</tt>.
3708</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3709
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]3710
3711<p>To learn how to add an intrinsic function, please see the
3712<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3713</p>
3714
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3715</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3716
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3717<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3718<div class="doc_subsection">
3719 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
3720</div>
3721
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3722<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3723
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3724<p>Variable argument support is defined in LLVM with the <a
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3725 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3726intrinsic functions. These functions are related to the similarly
3727named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3728
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3729<p>All of these functions operate on arguments that use a
3730target-specific value type "<tt>va_list</tt>". The LLVM assembly
3731language reference manual does not define what this type is, so all
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3732transformations should be prepared to handle these functions regardless of
3733the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3734
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]3735<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]3736instruction and the variable argument handling intrinsic functions are
3737used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3738
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3739<div class="doc_code">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3740<pre>
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3741define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3742 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3743 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3744 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3745 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3746
3747 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3748 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3749
3750 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3751 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3752 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3753 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3754 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3755
3756 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3757 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3758 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3759}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3760
3761declare void @llvm.va_start(i8*)
3762declare void @llvm.va_copy(i8*, i8*)
3763declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3764</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3765</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3766
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3767</div>
3768
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3769<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3770<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3771 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3772</div>
3773
3774
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3775<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3776<h5>Syntax:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3777<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3778<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3779<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
3780<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
3781href="#i_va_arg">va_arg</a></tt>.</p>
3782
3783<h5>Arguments:</h5>
3784
3785<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
3786
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3787<h5>Semantics:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3788
3789<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
3790macro available in C. In a target-dependent way, it initializes the
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3791<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]3792<tt>va_arg</tt> will produce the first variable argument passed to the function.
3793Unlike 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]3794last argument of the function as the compiler can figure that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3795
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3796</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3797
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3798<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3799<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3800 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3801</div>
3802
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3803<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3804<h5>Syntax:</h5>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3805<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3806<h5>Overview:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3807
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3808<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3809which 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]3810or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3811
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3812<h5>Arguments:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3813
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3814<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]3815
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3816<h5>Semantics:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3817
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3818<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]3819macro available in C. In a target-dependent way, it destroys the
3820<tt>va_list</tt> element to which the argument points. Calls to <a
3821href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
3822<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
3823<tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3824
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3825</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3826
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3827<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3828<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3829 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3830</div>
3831
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3832<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3833
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3834<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3835
3836<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3837 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3838</pre>
3839
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3840<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3841
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3842<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
3843from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3844
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3845<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3846
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3847<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]3848The 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]3849
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3850
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3851<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3852
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3853<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
3854macro available in C. In a target-dependent way, it copies the source
3855<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
3856intrinsic is necessary because the <tt><a href="#int_va_start">
3857llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
3858example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3859
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3860</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3861
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3862<!-- ======================================================================= -->
3863<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3864 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
3865</div>
3866
3867<div class="doc_text">
3868
3869<p>
3870LLVM support for <a href="GarbageCollection.html">Accurate Garbage
3871Collection</a> requires the implementation and generation of these intrinsics.
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3872These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3873stack</a>, as well as garbage collector implementations that require <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3874href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3875Front-ends for type-safe garbage collected languages should generate these
3876intrinsics to make use of the LLVM garbage collectors. For more details, see <a
3877href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
3878</p>
3879</div>
3880
3881<!-- _______________________________________________________________________ -->
3882<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3883 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3884</div>
3885
3886<div class="doc_text">
3887
3888<h5>Syntax:</h5>
3889
3890<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3891 declare void @llvm.gcroot(&lt;ty&gt;** %ptrloc, &lt;ty2&gt;* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3892</pre>
3893
3894<h5>Overview:</h5>
3895
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]3896<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]3897the code generator, and allows some metadata to be associated with it.</p>
3898
3899<h5>Arguments:</h5>
3900
3901<p>The first argument specifies the address of a stack object that contains the
3902root pointer. The second pointer (which must be either a constant or a global
3903value address) contains the meta-data to be associated with the root.</p>
3904
3905<h5>Semantics:</h5>
3906
3907<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
3908location. At compile-time, the code generator generates information to allow
3909the runtime to find the pointer at GC safe points.
3910</p>
3911
3912</div>
3913
3914
3915<!-- _______________________________________________________________________ -->
3916<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3917 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3918</div>
3919
3920<div class="doc_text">
3921
3922<h5>Syntax:</h5>
3923
3924<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3925 declare i8 * @llvm.gcread(i8 * %ObjPtr, i8 ** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3926</pre>
3927
3928<h5>Overview:</h5>
3929
3930<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
3931locations, allowing garbage collector implementations that require read
3932barriers.</p>
3933
3934<h5>Arguments:</h5>
3935
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3936<p>The second argument is the address to read from, which should be an address
3937allocated from the garbage collector. The first object is a pointer to the
3938start of the referenced object, if needed by the language runtime (otherwise
3939null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3940
3941<h5>Semantics:</h5>
3942
3943<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
3944instruction, but may be replaced with substantially more complex code by the
3945garbage collector runtime, as needed.</p>
3946
3947</div>
3948
3949
3950<!-- _______________________________________________________________________ -->
3951<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3952 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3953</div>
3954
3955<div class="doc_text">
3956
3957<h5>Syntax:</h5>
3958
3959<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3960 declare void @llvm.gcwrite(i8 * %P1, i8 * %Obj, i8 ** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3961</pre>
3962
3963<h5>Overview:</h5>
3964
3965<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
3966locations, allowing garbage collector implementations that require write
3967barriers (such as generational or reference counting collectors).</p>
3968
3969<h5>Arguments:</h5>
3970
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3971<p>The first argument is the reference to store, the second is the start of the
3972object to store it to, and the third is the address of the field of Obj to
3973store to. If the runtime does not require a pointer to the object, Obj may be
3974null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3975
3976<h5>Semantics:</h5>
3977
3978<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
3979instruction, but may be replaced with substantially more complex code by the
3980garbage collector runtime, as needed.</p>
3981
3982</div>
3983
3984
3985
3986<!-- ======================================================================= -->
3987<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3988 <a name="int_codegen">Code Generator Intrinsics</a>
3989</div>
3990
3991<div class="doc_text">
3992<p>
3993These intrinsics are provided by LLVM to expose special features that may only
3994be implemented with code generator support.
3995</p>
3996
3997</div>
3998
3999<!-- _______________________________________________________________________ -->
4000<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4001 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4002</div>
4003
4004<div class="doc_text">
4005
4006<h5>Syntax:</h5>
4007<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4008 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4009</pre>
4010
4011<h5>Overview:</h5>
4012
4013<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]4014The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
4015target-specific value indicating the return address of the current function
4016or one of its callers.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4017</p>
4018
4019<h5>Arguments:</h5>
4020
4021<p>
4022The argument to this intrinsic indicates which function to return the address
4023for. Zero indicates the calling function, one indicates its caller, etc. The
4024argument is <b>required</b> to be a constant integer value.
4025</p>
4026
4027<h5>Semantics:</h5>
4028
4029<p>
4030The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
4031the return address of the specified call frame, or zero if it cannot be
4032identified. The value returned by this intrinsic is likely to be incorrect or 0
4033for arguments other than zero, so it should only be used for debugging purposes.
4034</p>
4035
4036<p>
4037Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]4038aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4039source-language caller.
4040</p>
4041</div>
4042
4043
4044<!-- _______________________________________________________________________ -->
4045<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4046 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4047</div>
4048
4049<div class="doc_text">
4050
4051<h5>Syntax:</h5>
4052<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4053 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4054</pre>
4055
4056<h5>Overview:</h5>
4057
4058<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]4059The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
4060target-specific frame pointer value for the specified stack frame.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4061</p>
4062
4063<h5>Arguments:</h5>
4064
4065<p>
4066The argument to this intrinsic indicates which function to return the frame
4067pointer for. Zero indicates the calling function, one indicates its caller,
4068etc. The argument is <b>required</b> to be a constant integer value.
4069</p>
4070
4071<h5>Semantics:</h5>
4072
4073<p>
4074The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
4075the frame address of the specified call frame, or zero if it cannot be
4076identified. The value returned by this intrinsic is likely to be incorrect or 0
4077for arguments other than zero, so it should only be used for debugging purposes.
4078</p>
4079
4080<p>
4081Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]4082aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4083source-language caller.
4084</p>
4085</div>
4086
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4087<!-- _______________________________________________________________________ -->
4088<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4089 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4090</div>
4091
4092<div class="doc_text">
4093
4094<h5>Syntax:</h5>
4095<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4096 declare i8 *@llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4097</pre>
4098
4099<h5>Overview:</h5>
4100
4101<p>
4102The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4103the function stack, for use with <a href="#int_stackrestore">
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4104<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
4105features like scoped automatic variable sized arrays in C99.
4106</p>
4107
4108<h5>Semantics:</h5>
4109
4110<p>
4111This intrinsic returns a opaque pointer value that can be passed to <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4112href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4113<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
4114<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
4115state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
4116practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
4117that were allocated after the <tt>llvm.stacksave</tt> was executed.
4118</p>
4119
4120</div>
4121
4122<!-- _______________________________________________________________________ -->
4123<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4124 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4125</div>
4126
4127<div class="doc_text">
4128
4129<h5>Syntax:</h5>
4130<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4131 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4132</pre>
4133
4134<h5>Overview:</h5>
4135
4136<p>
4137The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
4138the function stack to the state it was in when the corresponding <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4139href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4140useful for implementing language features like scoped automatic variable sized
4141arrays in C99.
4142</p>
4143
4144<h5>Semantics:</h5>
4145
4146<p>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4147See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4148</p>
4149
4150</div>
4151
4152
4153<!-- _______________________________________________________________________ -->
4154<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4155 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4156</div>
4157
4158<div class="doc_text">
4159
4160<h5>Syntax:</h5>
4161<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4162 declare void @llvm.prefetch(i8 * &lt;address&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4163 i32 &lt;rw&gt;, i32 &lt;locality&gt;)
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4164</pre>
4165
4166<h5>Overview:</h5>
4167
4168
4169<p>
4170The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4171a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
4172no
4173effect on the behavior of the program but can change its performance
Chris Lattner2a615362005-02-28 19:47:14 +0000[diff] [blame]4174characteristics.
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4175</p>
4176
4177<h5>Arguments:</h5>
4178
4179<p>
4180<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
4181determining if the fetch should be for a read (0) or write (1), and
4182<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattneraeffb4a2005-03-07 20:31:38 +0000[diff] [blame]4183locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4184<tt>locality</tt> arguments must be constant integers.
4185</p>
4186
4187<h5>Semantics:</h5>
4188
4189<p>
4190This intrinsic does not modify the behavior of the program. In particular,
4191prefetches cannot trap and do not produce a value. On targets that support this
4192intrinsic, the prefetch can provide hints to the processor cache for better
4193performance.
4194</p>
4195
4196</div>
4197
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4198<!-- _______________________________________________________________________ -->
4199<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4200 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4201</div>
4202
4203<div class="doc_text">
4204
4205<h5>Syntax:</h5>
4206<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4207 declare void @llvm.pcmarker( i32 &lt;id&gt; )
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4208</pre>
4209
4210<h5>Overview:</h5>
4211
4212
4213<p>
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4214The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
4215(PC) in a region of
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4216code to simulators and other tools. The method is target specific, but it is
4217expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]4218The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnerd07c3f42005-11-15 06:07:55 +0000[diff] [blame]4219after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb3e7afd2006-03-24 07:16:10 +0000[diff] [blame]4220optimizations. The intended use is to be inserted after optimizations to allow
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4221correlations of simulation runs.
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4222</p>
4223
4224<h5>Arguments:</h5>
4225
4226<p>
4227<tt>id</tt> is a numerical id identifying the marker.
4228</p>
4229
4230<h5>Semantics:</h5>
4231
4232<p>
4233This intrinsic does not modify the behavior of the program. Backends that do not
4234support this intrinisic may ignore it.
4235</p>
4236
4237</div>
4238
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4239<!-- _______________________________________________________________________ -->
4240<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4241 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4242</div>
4243
4244<div class="doc_text">
4245
4246<h5>Syntax:</h5>
4247<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4248 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4249</pre>
4250
4251<h5>Overview:</h5>
4252
4253
4254<p>
4255The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
4256counter register (or similar low latency, high accuracy clocks) on those targets
4257that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
4258As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
4259should only be used for small timings.
4260</p>
4261
4262<h5>Semantics:</h5>
4263
4264<p>
4265When directly supported, reading the cycle counter should not modify any memory.
4266Implementations are allowed to either return a application specific value or a
4267system wide value. On backends without support, this is lowered to a constant 0.
4268</p>
4269
4270</div>
4271
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4272<!-- ======================================================================= -->
4273<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4274 <a name="int_libc">Standard C Library Intrinsics</a>
4275</div>
4276
4277<div class="doc_text">
4278<p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4279LLVM provides intrinsics for a few important standard C library functions.
4280These intrinsics allow source-language front-ends to pass information about the
4281alignment of the pointer arguments to the code generator, providing opportunity
4282for more efficient code generation.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4283</p>
4284
4285</div>
4286
4287<!-- _______________________________________________________________________ -->
4288<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4289 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4290</div>
4291
4292<div class="doc_text">
4293
4294<h5>Syntax:</h5>
4295<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4296 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4297 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4298 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4299 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4300</pre>
4301
4302<h5>Overview:</h5>
4303
4304<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4305The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4306location to the destination location.
4307</p>
4308
4309<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4310Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4311intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4312</p>
4313
4314<h5>Arguments:</h5>
4315
4316<p>
4317The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4318the source. The third argument is an integer argument
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4319specifying the number of bytes to copy, and the fourth argument is the alignment
4320of the source and destination locations.
4321</p>
4322
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4323<p>
4324If 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]4325the caller guarantees that both the source and destination pointers are aligned
4326to that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4327</p>
4328
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4329<h5>Semantics:</h5>
4330
4331<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4332The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4333location to the destination location, which are not allowed to overlap. It
4334copies "len" bytes of memory over. If the argument is known to be aligned to
4335some boundary, this can be specified as the fourth argument, otherwise it should
4336be set to 0 or 1.
4337</p>
4338</div>
4339
4340
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4341<!-- _______________________________________________________________________ -->
4342<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4343 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4344</div>
4345
4346<div class="doc_text">
4347
4348<h5>Syntax:</h5>
4349<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4350 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4351 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4352 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4353 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4354</pre>
4355
4356<h5>Overview:</h5>
4357
4358<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4359The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
4360location to the destination location. It is similar to the
4361'<tt>llvm.memcmp</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4362</p>
4363
4364<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4365Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
4366intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4367</p>
4368
4369<h5>Arguments:</h5>
4370
4371<p>
4372The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4373the source. The third argument is an integer argument
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4374specifying the number of bytes to copy, and the fourth argument is the alignment
4375of the source and destination locations.
4376</p>
4377
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4378<p>
4379If 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]4380the caller guarantees that the source and destination pointers are aligned to
4381that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4382</p>
4383
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4384<h5>Semantics:</h5>
4385
4386<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4387The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4388location to the destination location, which may overlap. It
4389copies "len" bytes of memory over. If the argument is known to be aligned to
4390some boundary, this can be specified as the fourth argument, otherwise it should
4391be set to 0 or 1.
4392</p>
4393</div>
4394
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4395
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4396<!-- _______________________________________________________________________ -->
4397<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4398 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4399</div>
4400
4401<div class="doc_text">
4402
4403<h5>Syntax:</h5>
4404<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4405 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4406 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4407 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4408 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4409</pre>
4410
4411<h5>Overview:</h5>
4412
4413<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4414The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4415byte value.
4416</p>
4417
4418<p>
4419Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
4420does not return a value, and takes an extra alignment argument.
4421</p>
4422
4423<h5>Arguments:</h5>
4424
4425<p>
4426The first argument is a pointer to the destination to fill, the second is the
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4427byte value to fill it with, the third argument is an integer
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4428argument specifying the number of bytes to fill, and the fourth argument is the
4429known alignment of destination location.
4430</p>
4431
4432<p>
4433If 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]4434the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4435</p>
4436
4437<h5>Semantics:</h5>
4438
4439<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4440The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
4441the
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4442destination location. If the argument is known to be aligned to some boundary,
4443this can be specified as the fourth argument, otherwise it should be set to 0 or
44441.
4445</p>
4446</div>
4447
4448
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4449<!-- _______________________________________________________________________ -->
4450<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4451 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4452</div>
4453
4454<div class="doc_text">
4455
4456<h5>Syntax:</h5>
4457<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4458 declare float @llvm.sqrt.f32(float %Val)
4459 declare double @llvm.sqrt.f64(double %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4460</pre>
4461
4462<h5>Overview:</h5>
4463
4464<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4465The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4466returning the same value as the libm '<tt>sqrt</tt>' function would. Unlike
4467<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
4468negative numbers (which allows for better optimization).
4469</p>
4470
4471<h5>Arguments:</h5>
4472
4473<p>
4474The argument and return value are floating point numbers of the same type.
4475</p>
4476
4477<h5>Semantics:</h5>
4478
4479<p>
Dan Gohmand6257fe2007-07-16 14:37:41 +0000[diff] [blame]4480This function returns the sqrt of the specified operand if it is a nonnegative
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4481floating point number.
4482</p>
4483</div>
4484
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4485<!-- _______________________________________________________________________ -->
4486<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4487 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4488</div>
4489
4490<div class="doc_text">
4491
4492<h5>Syntax:</h5>
4493<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4494 declare float @llvm.powi.f32(float %Val, i32 %power)
4495 declare double @llvm.powi.f64(double %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4496</pre>
4497
4498<h5>Overview:</h5>
4499
4500<p>
4501The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
4502specified (positive or negative) power. The order of evaluation of
4503multiplications is not defined.
4504</p>
4505
4506<h5>Arguments:</h5>
4507
4508<p>
4509The second argument is an integer power, and the first is a value to raise to
4510that power.
4511</p>
4512
4513<h5>Semantics:</h5>
4514
4515<p>
4516This function returns the first value raised to the second power with an
4517unspecified sequence of rounding operations.</p>
4518</div>
4519
4520
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4521<!-- ======================================================================= -->
4522<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4523 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4524</div>
4525
4526<div class="doc_text">
4527<p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4528LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4529These allow efficient code generation for some algorithms.
4530</p>
4531
4532</div>
4533
4534<!-- _______________________________________________________________________ -->
4535<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4536 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4537</div>
4538
4539<div class="doc_text">
4540
4541<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4542<p>This is an overloaded intrinsic function. You can use bswap on any integer
4543type that is an even number of bytes (i.e. BitWidth % 16 == 0). Note the suffix
4544that includes the type for the result and the operand.
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4545<pre>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4546 declare i16 @llvm.bswap.i16.i16(i16 &lt;id&gt;)
4547 declare i32 @llvm.bswap.i32.i32(i32 &lt;id&gt;)
Reid Spencer543ab1d2007-04-02 00:19:52 +0000[diff] [blame]4548 declare i64 @llvm.bswap.i64.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4549</pre>
4550
4551<h5>Overview:</h5>
4552
4553<p>
Reid Spencer338ea092007-04-02 02:25:19 +0000[diff] [blame]4554The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4555values with an even number of bytes (positive multiple of 16 bits). These are
4556useful for performing operations on data that is not in the target's native
4557byte order.
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4558</p>
4559
4560<h5>Semantics:</h5>
4561
4562<p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4563The <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]4564and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
4565intrinsic returns an i32 value that has the four bytes of the input i32
4566swapped, 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]4567i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48.i48</tt>,
4568<tt>llvm.bswap.i64.i64</tt> and other intrinsics extend this concept to
4569additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4570</p>
4571
4572</div>
4573
4574<!-- _______________________________________________________________________ -->
4575<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4576 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4577</div>
4578
4579<div class="doc_text">
4580
4581<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4582<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
4583width. Not all targets support all bit widths however.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4584<pre>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4585 declare i32 @llvm.ctpop.i8 (i8 &lt;src&gt;)
4586 declare i32 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4587 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4588 declare i32 @llvm.ctpop.i64(i64 &lt;src&gt;)
4589 declare i32 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4590</pre>
4591
4592<h5>Overview:</h5>
4593
4594<p>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4595The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
4596value.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4597</p>
4598
4599<h5>Arguments:</h5>
4600
4601<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]4602The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4603integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4604</p>
4605
4606<h5>Semantics:</h5>
4607
4608<p>
4609The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
4610</p>
4611</div>
4612
4613<!-- _______________________________________________________________________ -->
4614<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]4615 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4616</div>
4617
4618<div class="doc_text">
4619
4620<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4621<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
4622integer bit width. Not all targets support all bit widths however.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4623<pre>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4624 declare i32 @llvm.ctlz.i8 (i8 &lt;src&gt;)
4625 declare i32 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4626 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4627 declare i32 @llvm.ctlz.i64(i64 &lt;src&gt;)
4628 declare i32 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4629</pre>
4630
4631<h5>Overview:</h5>
4632
4633<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4634The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
4635leading zeros in a variable.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4636</p>
4637
4638<h5>Arguments:</h5>
4639
4640<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]4641The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4642integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4643</p>
4644
4645<h5>Semantics:</h5>
4646
4647<p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4648The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
4649in 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]4650of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4651</p>
4652</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4653
4654
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4655
4656<!-- _______________________________________________________________________ -->
4657<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]4658 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4659</div>
4660
4661<div class="doc_text">
4662
4663<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4664<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
4665integer bit width. Not all targets support all bit widths however.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4666<pre>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4667 declare i32 @llvm.cttz.i8 (i8 &lt;src&gt;)
4668 declare i32 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4669 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4670 declare i32 @llvm.cttz.i64(i64 &lt;src&gt;)
4671 declare i32 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4672</pre>
4673
4674<h5>Overview:</h5>
4675
4676<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4677The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
4678trailing zeros.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4679</p>
4680
4681<h5>Arguments:</h5>
4682
4683<p>
4684The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4685integer type. The return type must match the argument type.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4686</p>
4687
4688<h5>Semantics:</h5>
4689
4690<p>
4691The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
4692in a variable. If the src == 0 then the result is the size in bits of the type
4693of src. For example, <tt>llvm.cttz(2) = 1</tt>.
4694</p>
4695</div>
4696
Reid Spencer497d93e2007-04-01 08:27:01 +0000[diff] [blame]4697<!-- _______________________________________________________________________ -->
4698<div class="doc_subsubsection">
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]4699 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4700</div>
4701
4702<div class="doc_text">
4703
4704<h5>Syntax:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]4705<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4706on any integer bit width.
4707<pre>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]4708 declare i17 @llvm.part.select.i17.i17 (i17 %val, i32 %loBit, i32 %hiBit)
4709 declare i29 @llvm.part.select.i29.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4710</pre>
4711
4712<h5>Overview:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]4713<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4714range of bits from an integer value and returns them in the same bit width as
4715the original value.</p>
4716
4717<h5>Arguments:</h5>
4718<p>The first argument, <tt>%val</tt> and the result may be integer types of
4719any bit width but they must have the same bit width. The second and third
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4720arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4721
4722<h5>Semantics:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]4723<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4724of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
4725<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
4726operates in forward mode.</p>
4727<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
4728right by <tt>%loBit</tt> bits and then ANDing it with a mask with
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4729only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
4730<ol>
4731 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
4732 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
4733 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
4734 to determine the number of bits to retain.</li>
4735 <li>A mask of the retained bits is created by shifting a -1 value.</li>
4736 <li>The mask is ANDed with <tt>%val</tt> to produce the result.
4737</ol>
Reid Spencerd6a85b52007-05-14 16:14:57 +0000[diff] [blame]4738<p>In reverse mode, a similar computation is made except that the bits are
4739returned in the reverse order. So, for example, if <tt>X</tt> has the value
4740<tt>i16 0x0ACF (101011001111)</tt> and we apply
4741<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
4742<tt>i16 0x0026 (000000100110)</tt>.</p>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4743</div>
4744
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]4745<div class="doc_subsubsection">
4746 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
4747</div>
4748
4749<div class="doc_text">
4750
4751<h5>Syntax:</h5>
4752<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
4753on any integer bit width.
4754<pre>
4755 declare i17 @llvm.part.set.i17.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
4756 declare i29 @llvm.part.set.i29.i29.i9 (i29 %val, i9 %repl, i32 %lo, i32 %hi)
4757</pre>
4758
4759<h5>Overview:</h5>
4760<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
4761of bits in an integer value with another integer value. It returns the integer
4762with the replaced bits.</p>
4763
4764<h5>Arguments:</h5>
4765<p>The first argument, <tt>%val</tt> and the result may be integer types of
4766any bit width but they must have the same bit width. <tt>%val</tt> is the value
4767whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
4768integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
4769type since they specify only a bit index.</p>
4770
4771<h5>Semantics:</h5>
4772<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
4773of operation: forwards and reverse. If <tt>%lo</tt> is greater than
4774<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
4775operates in forward mode.</p>
4776<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
4777truncating it down to the size of the replacement area or zero extending it
4778up to that size.</p>
4779<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
4780are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
4781in <tt>%repl</tt> replaces the <tt>%lo</tt>th bit in <tt>%val</tt> and etc. up
4782to the <tt>%hi</tt>th bit.
Reid Spencerc6749c42007-05-14 16:50:20 +0000[diff] [blame]4783<p>In reverse mode, a similar computation is made except that the bits are
4784reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
4785<tt>%hi</tt> bit in <tt>%val</tt> and etc. down to the <tt>%lo</tt>th bit.
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]4786<h5>Examples:</h5>
4787<pre>
Reid Spencerf0dbf642007-04-12 01:03:03 +0000[diff] [blame]4788 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
Reid Spencerc6749c42007-05-14 16:50:20 +0000[diff] [blame]4789 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
4790 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
4791 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
Reid Spencerf0dbf642007-04-12 01:03:03 +0000[diff] [blame]4792 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]4793</pre>
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]4794</div>
4795
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4796<!-- ======================================================================= -->
4797<div class="doc_subsection">
4798 <a name="int_debugger">Debugger Intrinsics</a>
4799</div>
4800
4801<div class="doc_text">
4802<p>
4803The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
4804are described in the <a
4805href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
4806Debugging</a> document.
4807</p>
4808</div>
4809
4810
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]4811<!-- ======================================================================= -->
4812<div class="doc_subsection">
4813 <a name="int_eh">Exception Handling Intrinsics</a>
4814</div>
4815
4816<div class="doc_text">
4817<p> The LLVM exception handling intrinsics (which all start with
4818<tt>llvm.eh.</tt> prefix), are described in the <a
4819href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
4820Handling</a> document. </p>
4821</div>
4822
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]4823<!-- ======================================================================= -->
4824<div class="doc_subsection">
4825 <a name="int_general">General Intrinsics</a>
4826</div>
4827
4828<div class="doc_text">
4829<p> This class of intrinsics is designed to be generic and has
4830no specific purpose. </p>
4831</div>
4832
4833<!-- _______________________________________________________________________ -->
4834<div class="doc_subsubsection">
4835 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
4836</div>
4837
4838<div class="doc_text">
4839
4840<h5>Syntax:</h5>
4841<pre>
Tanya Lattnerd2e84422007-06-18 23:42:37 +0000[diff] [blame]4842 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]4843</pre>
4844
4845<h5>Overview:</h5>
4846
4847<p>
4848The '<tt>llvm.var.annotation</tt>' intrinsic
4849</p>
4850
4851<h5>Arguments:</h5>
4852
4853<p>
Tanya Lattnerd2e84422007-06-18 23:42:37 +0000[diff] [blame]4854The first argument is a pointer to a value, the second is a pointer to a
4855global string, the third is a pointer to a global string which is the source
4856file name, and the last argument is the line number.
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]4857</p>
4858
4859<h5>Semantics:</h5>
4860
4861<p>
4862This intrinsic allows annotation of local variables with arbitrary strings.
4863This can be useful for special purpose optimizations that want to look for these
4864 annotations. These have no other defined use, they are ignored by code
4865 generation and optimization.
4866</div>
4867
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]4868
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4869<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4870<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]4871<address>
4872 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
4873 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
4874 <a href="http://validator.w3.org/check/referer"><img
4875 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!" /></a>
4876
4877 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]4878 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]4879 Last modified: $Date$
4880</address>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4881</body>
4882</html>