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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
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7 <meta name="author" content="Chris Lattner">
8 <meta name="description"
9 content="LLVM Assembly Language Reference Manual.">
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11</head>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]14
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]15<div class="doc_title"> LLVM Language Reference Manual </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a></li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]24 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]25 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]26 <li><a href="#functionstructure">Functions</a></li>
27 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]28 </ol>
29 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]30 <li><a href="#typesystem">Type System</a>
31 <ol>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]32 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]33 <ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]34 <li><a href="#t_classifications">Type Classifications</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]35 </ol>
36 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]37 <li><a href="#t_derived">Derived Types</a>
38 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]39 <li><a href="#t_array">Array Type</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]40 <li><a href="#t_function">Function Type</a></li>
41 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]42 <li><a href="#t_struct">Structure Type</a></li>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]43 <li><a href="#t_packed">Packed Type</a></li>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]44 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]45 </ol>
46 </li>
47 </ol>
48 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]49 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]50 <ol>
51 <li><a href="#simpleconstants">Simple Constants</a>
52 <li><a href="#aggregateconstants">Aggregate Constants</a>
53 <li><a href="#globalconstants">Global Variable and Function Addresses</a>
54 <li><a href="#undefvalues">Undefined Values</a>
55 <li><a href="#constantexprs">Constant Expressions</a>
56 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]57 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]58 <li><a href="#othervalues">Other Values</a>
59 <ol>
60 <li><a href="#inlineasm">Inline Assembler Expressions</a>
61 </ol>
62 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]63 <li><a href="#instref">Instruction Reference</a>
64 <ol>
65 <li><a href="#terminators">Terminator Instructions</a>
66 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]67 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
68 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]69 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
70 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]71 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]72 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]73 </ol>
74 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]75 <li><a href="#binaryops">Binary Operations</a>
76 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]77 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
78 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
79 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
80 <li><a href="#i_div">'<tt>div</tt>' Instruction</a></li>
81 <li><a href="#i_rem">'<tt>rem</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]82 <li><a href="#i_setcc">'<tt>set<i>cc</i></tt>' Instructions</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]83 </ol>
84 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]85 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
86 <ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]87 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]88 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]89 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
90 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
91 <li><a href="#i_shr">'<tt>shr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]92 </ol>
93 </li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]94 <li><a href="#vectorops">Vector Operations</a>
95 <ol>
96 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
97 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
98 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]99 <li><a href="#i_vsetint">'<tt>vsetint</tt>' Instruction</a></li>
100 <li><a href="#i_vsetfp">'<tt>vsetfp</tt>' Instruction</a></li>
101 <li><a href="#i_vselect">'<tt>vselect</tt>' Instruction</a></li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]102 </ol>
103 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]104 <li><a href="#memoryops">Memory Access Operations</a>
105 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]106 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
107 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
108 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]109 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
110 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
111 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]112 </ol>
113 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]114 <li><a href="#otherops">Other Operations</a>
115 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]116 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]117 <li><a href="#i_cast">'<tt>cast .. to</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]118 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]119 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]120 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]121 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]122 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]123 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]124 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]125 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]126 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]127 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
128 <ol>
129 <li><a href="#i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
130 <li><a href="#i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
131 <li><a href="#i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
132 </ol>
133 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]134 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
135 <ol>
136 <li><a href="#i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
137 <li><a href="#i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
138 <li><a href="#i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
139 </ol>
140 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]141 <li><a href="#int_codegen">Code Generator Intrinsics</a>
142 <ol>
143 <li><a href="#i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
144 <li><a href="#i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]145 <li><a href="#i_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
146 <li><a href="#i_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]147 <li><a href="#i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]148 <li><a href="#i_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]149 <li><a href="#i_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]150 </ol>
151 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]152 <li><a href="#int_libc">Standard C Library Intrinsics</a>
153 <ol>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]154 <li><a href="#i_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
155 <li><a href="#i_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
156 <li><a href="#i_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]157 <li><a href="#i_isunordered">'<tt>llvm.isunordered.*</tt>' Intrinsic</a></li>
158 <li><a href="#i_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]159
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]160 </ol>
161 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]162 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]163 <ol>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]164 <li><a href="#i_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]165 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
166 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
167 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]168 </ol>
169 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]170 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]171 </ol>
172 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]173</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]174
175<div class="doc_author">
176 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
177 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]178</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]179
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]180<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]181<div class="doc_section"> <a name="abstract">Abstract </a></div>
182<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]183
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]184<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]185<p>This document is a reference manual for the LLVM assembly language.
186LLVM is an SSA based representation that provides type safety,
187low-level operations, flexibility, and the capability of representing
188'all' high-level languages cleanly. It is the common code
189representation used throughout all phases of the LLVM compilation
190strategy.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]191</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]192
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]193<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]194<div class="doc_section"> <a name="introduction">Introduction</a> </div>
195<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]196
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]197<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]198
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]199<p>The LLVM code representation is designed to be used in three
200different forms: as an in-memory compiler IR, as an on-disk bytecode
201representation (suitable for fast loading by a Just-In-Time compiler),
202and as a human readable assembly language representation. This allows
203LLVM to provide a powerful intermediate representation for efficient
204compiler transformations and analysis, while providing a natural means
205to debug and visualize the transformations. The three different forms
206of LLVM are all equivalent. This document describes the human readable
207representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]208
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]209<p>The LLVM representation aims to be light-weight and low-level
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]210while being expressive, typed, and extensible at the same time. It
211aims to be a "universal IR" of sorts, by being at a low enough level
212that high-level ideas may be cleanly mapped to it (similar to how
213microprocessors are "universal IR's", allowing many source languages to
214be mapped to them). By providing type information, LLVM can be used as
215the target of optimizations: for example, through pointer analysis, it
216can be proven that a C automatic variable is never accessed outside of
217the current function... allowing it to be promoted to a simple SSA
218value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]219
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_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]224
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]225<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]226
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]227<p>It is important to note that this document describes 'well formed'
228LLVM assembly language. There is a difference between what the parser
229accepts and what is considered 'well formed'. For example, the
230following instruction is syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]231
232<pre>
233 %x = <a href="#i_add">add</a> int 1, %x
234</pre>
235
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]236<p>...because the definition of <tt>%x</tt> does not dominate all of
237its uses. The LLVM infrastructure provides a verification pass that may
238be used to verify that an LLVM module is well formed. This pass is
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]239automatically run by the parser after parsing input assembly and by
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]240the optimizer before it outputs bytecode. The violations pointed out
241by the verifier pass indicate bugs in transformation passes or input to
242the parser.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]243
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]244<!-- Describe the typesetting conventions here. --> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]245
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]246<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]247<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]248<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]249
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]250<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]251
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]252<p>LLVM uses three different forms of identifiers, for different
253purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]254
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]255<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]256 <li>Named values are represented as a string of characters with a '%' prefix.
257 For example, %foo, %DivisionByZero, %a.really.long.identifier. The actual
258 regular expression used is '<tt>%[a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
259 Identifiers which require other characters in their names can be surrounded
260 with quotes. In this way, anything except a <tt>"</tt> character can be used
261 in a name.</li>
262
263 <li>Unnamed values are represented as an unsigned numeric value with a '%'
264 prefix. For example, %12, %2, %44.</li>
265
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]266 <li>Constants, which are described in a <a href="#constants">section about
267 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]268</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]269
270<p>LLVM requires that values start with a '%' sign for two reasons: Compilers
271don't need to worry about name clashes with reserved words, and the set of
272reserved words may be expanded in the future without penalty. Additionally,
273unnamed identifiers allow a compiler to quickly come up with a temporary
274variable without having to avoid symbol table conflicts.</p>
275
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]276<p>Reserved words in LLVM are very similar to reserved words in other
277languages. There are keywords for different opcodes ('<tt><a
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]278href="#i_add">add</a></tt>', '<tt><a href="#i_cast">cast</a></tt>', '<tt><a
279href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a
280href="#t_void">void</a></tt>', '<tt><a href="#t_uint">uint</a></tt>', etc...),
281and others. These reserved words cannot conflict with variable names, because
282none of them start with a '%' character.</p>
283
284<p>Here is an example of LLVM code to multiply the integer variable
285'<tt>%X</tt>' by 8:</p>
286
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]287<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]288
289<pre>
290 %result = <a href="#i_mul">mul</a> uint %X, 8
291</pre>
292
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]293<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]294
295<pre>
296 %result = <a href="#i_shl">shl</a> uint %X, ubyte 3
297</pre>
298
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]299<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]300
301<pre>
302 <a href="#i_add">add</a> uint %X, %X <i>; yields {uint}:%0</i>
303 <a href="#i_add">add</a> uint %0, %0 <i>; yields {uint}:%1</i>
304 %result = <a href="#i_add">add</a> uint %1, %1
305</pre>
306
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]307<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
308important lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]309
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]310<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]311
312 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
313 line.</li>
314
315 <li>Unnamed temporaries are created when the result of a computation is not
316 assigned to a named value.</li>
317
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]318 <li>Unnamed temporaries are numbered sequentially</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]319
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]320</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]321
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]322<p>...and it also shows a convention that we follow in this document. When
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]323demonstrating instructions, we will follow an instruction with a comment that
324defines the type and name of value produced. Comments are shown in italic
325text.</p>
326
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]327</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]328
329<!-- *********************************************************************** -->
330<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
331<!-- *********************************************************************** -->
332
333<!-- ======================================================================= -->
334<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
335</div>
336
337<div class="doc_text">
338
339<p>LLVM programs are composed of "Module"s, each of which is a
340translation unit of the input programs. Each module consists of
341functions, global variables, and symbol table entries. Modules may be
342combined together with the LLVM linker, which merges function (and
343global variable) definitions, resolves forward declarations, and merges
344symbol table entries. Here is an example of the "hello world" module:</p>
345
346<pre><i>; Declare the string constant as a global constant...</i>
347<a href="#identifiers">%.LC0</a> = <a href="#linkage_internal">internal</a> <a
348 href="#globalvars">constant</a> <a href="#t_array">[13 x sbyte]</a> c"hello world\0A\00" <i>; [13 x sbyte]*</i>
349
350<i>; External declaration of the puts function</i>
351<a href="#functionstructure">declare</a> int %puts(sbyte*) <i>; int(sbyte*)* </i>
352
353<i>; Definition of main function</i>
354int %main() { <i>; int()* </i>
355 <i>; Convert [13x sbyte]* to sbyte *...</i>
356 %cast210 = <a
357 href="#i_getelementptr">getelementptr</a> [13 x sbyte]* %.LC0, long 0, long 0 <i>; sbyte*</i>
358
359 <i>; Call puts function to write out the string to stdout...</i>
360 <a
361 href="#i_call">call</a> int %puts(sbyte* %cast210) <i>; int</i>
362 <a
363 href="#i_ret">ret</a> int 0<br>}<br></pre>
364
365<p>This example is made up of a <a href="#globalvars">global variable</a>
366named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
367function, and a <a href="#functionstructure">function definition</a>
368for "<tt>main</tt>".</p>
369
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]370<p>In general, a module is made up of a list of global values,
371where both functions and global variables are global values. Global values are
372represented by a pointer to a memory location (in this case, a pointer to an
373array of char, and a pointer to a function), and have one of the following <a
374href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]375
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]376</div>
377
378<!-- ======================================================================= -->
379<div class="doc_subsection">
380 <a name="linkage">Linkage Types</a>
381</div>
382
383<div class="doc_text">
384
385<p>
386All Global Variables and Functions have one of the following types of linkage:
387</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]388
389<dl>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]390
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]391 <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]392
393 <dd>Global values with internal linkage are only directly accessible by
394 objects in the current module. In particular, linking code into a module with
395 an internal global value may cause the internal to be renamed as necessary to
396 avoid collisions. Because the symbol is internal to the module, all
397 references can be updated. This corresponds to the notion of the
398 '<tt>static</tt>' keyword in C, or the idea of "anonymous namespaces" in C++.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]399 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]400
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]401 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]402
403 <dd>"<tt>linkonce</tt>" linkage is similar to <tt>internal</tt> linkage, with
404 the twist that linking together two modules defining the same
405 <tt>linkonce</tt> globals will cause one of the globals to be discarded. This
406 is typically used to implement inline functions. Unreferenced
407 <tt>linkonce</tt> globals are allowed to be discarded.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]408 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]409
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]410 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]411
412 <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage,
413 except that unreferenced <tt>weak</tt> globals may not be discarded. This is
414 used to implement constructs in C such as "<tt>int X;</tt>" at global scope.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]415 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]416
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]417 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]418
419 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
420 pointer to array type. When two global variables with appending linkage are
421 linked together, the two global arrays are appended together. This is the
422 LLVM, typesafe, equivalent of having the system linker append together
423 "sections" with identical names when .o files are linked.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]424 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]425
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]426 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]427
428 <dd>If none of the above identifiers are used, the global is externally
429 visible, meaning that it participates in linkage and can be used to resolve
430 external symbol references.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]431 </dd>
432</dl>
433
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]434<p><a name="linkage_external">For example, since the "<tt>.LC0</tt>"
435variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
436variable and was linked with this one, one of the two would be renamed,
437preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
438external (i.e., lacking any linkage declarations), they are accessible
439outside of the current module. It is illegal for a function <i>declaration</i>
440to have any linkage type other than "externally visible".</a></p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]441
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]442</div>
443
444<!-- ======================================================================= -->
445<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]446 <a name="callingconv">Calling Conventions</a>
447</div>
448
449<div class="doc_text">
450
451<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
452and <a href="#i_invoke">invokes</a> can all have an optional calling convention
453specified for the call. The calling convention of any pair of dynamic
454caller/callee must match, or the behavior of the program is undefined. The
455following calling conventions are supported by LLVM, and more may be added in
456the future:</p>
457
458<dl>
459 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
460
461 <dd>This calling convention (the default if no other calling convention is
462 specified) matches the target C calling conventions. This calling convention
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]463 supports varargs function calls and tolerates some mismatch in the declared
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]464 prototype and implemented declaration of the function (as does normal C).
465 </dd>
466
467 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
468
469 <dd>This calling convention attempts to make calls as fast as possible
470 (e.g. by passing things in registers). This calling convention allows the
471 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner8cdc5bc2005-05-06 23:08:23 +0000[diff] [blame]472 without having to conform to an externally specified ABI. Implementations of
473 this convention should allow arbitrary tail call optimization to be supported.
474 This calling convention does not support varargs and requires the prototype of
475 all callees to exactly match the prototype of the function definition.
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]476 </dd>
477
478 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
479
480 <dd>This calling convention attempts to make code in the caller as efficient
481 as possible under the assumption that the call is not commonly executed. As
482 such, these calls often preserve all registers so that the call does not break
483 any live ranges in the caller side. This calling convention does not support
484 varargs and requires the prototype of all callees to exactly match the
485 prototype of the function definition.
486 </dd>
487
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]488 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]489
490 <dd>Any calling convention may be specified by number, allowing
491 target-specific calling conventions to be used. Target specific calling
492 conventions start at 64.
493 </dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]494</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]495
496<p>More calling conventions can be added/defined on an as-needed basis, to
497support pascal conventions or any other well-known target-independent
498convention.</p>
499
500</div>
501
502<!-- ======================================================================= -->
503<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]504 <a name="globalvars">Global Variables</a>
505</div>
506
507<div class="doc_text">
508
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]509<p>Global variables define regions of memory allocated at compilation time
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]510instead of run-time. Global variables may optionally be initialized, may have
511an explicit section to be placed in, and may
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]512have an optional explicit alignment specified. A
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]513variable may be defined as a global "constant," which indicates that the
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]514contents of the variable will <b>never</b> be modified (enabling better
515optimization, allowing the global data to be placed in the read-only section of
516an executable, etc). Note that variables that need runtime initialization
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]517cannot be marked "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]518
519<p>
520LLVM explicitly allows <em>declarations</em> of global variables to be marked
521constant, even if the final definition of the global is not. This capability
522can be used to enable slightly better optimization of the program, but requires
523the language definition to guarantee that optimizations based on the
524'constantness' are valid for the translation units that do not include the
525definition.
526</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]527
528<p>As SSA values, global variables define pointer values that are in
529scope (i.e. they dominate) all basic blocks in the program. Global
530variables always define a pointer to their "content" type because they
531describe a region of memory, and all memory objects in LLVM are
532accessed through pointers.</p>
533
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]534<p>LLVM allows an explicit section to be specified for globals. If the target
535supports it, it will emit globals to the section specified.</p>
536
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]537<p>An explicit alignment may be specified for a global. If not present, or if
538the alignment is set to zero, the alignment of the global is set by the target
539to whatever it feels convenient. If an explicit alignment is specified, the
540global is forced to have at least that much alignment. All alignments must be
541a power of 2.</p>
542
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]543</div>
544
545
546<!-- ======================================================================= -->
547<div class="doc_subsection">
548 <a name="functionstructure">Functions</a>
549</div>
550
551<div class="doc_text">
552
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]553<p>LLVM function definitions consist of an optional <a href="#linkage">linkage
554type</a>, an optional <a href="#callingconv">calling convention</a>, a return
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]555type, a function name, a (possibly empty) argument list, an optional section,
556an optional alignment, an opening curly brace,
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]557a list of basic blocks, and a closing curly brace. LLVM function declarations
558are defined with the "<tt>declare</tt>" keyword, an optional <a
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]559href="#callingconv">calling convention</a>, a return type, a function name,
560a possibly empty list of arguments, and an optional alignment.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]561
562<p>A function definition contains a list of basic blocks, forming the CFG for
563the function. Each basic block may optionally start with a label (giving the
564basic block a symbol table entry), contains a list of instructions, and ends
565with a <a href="#terminators">terminator</a> instruction (such as a branch or
566function return).</p>
567
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]568<p>The first basic block in a program is special in two ways: it is immediately
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]569executed on entrance to the function, and it is not allowed to have predecessor
570basic blocks (i.e. there can not be any branches to the entry block of a
571function). Because the block can have no predecessors, it also cannot have any
572<a href="#i_phi">PHI nodes</a>.</p>
573
574<p>LLVM functions are identified by their name and type signature. Hence, two
575functions with the same name but different parameter lists or return values are
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]576considered different functions, and LLVM will resolve references to each
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]577appropriately.</p>
578
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]579<p>LLVM allows an explicit section to be specified for functions. If the target
580supports it, it will emit functions to the section specified.</p>
581
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]582<p>An explicit alignment may be specified for a function. If not present, or if
583the alignment is set to zero, the alignment of the function is set by the target
584to whatever it feels convenient. If an explicit alignment is specified, the
585function is forced to have at least that much alignment. All alignments must be
586a power of 2.</p>
587
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]588</div>
589
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]590<!-- ======================================================================= -->
591<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]592 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]593</div>
594
595<div class="doc_text">
596<p>
597Modules may contain "module-level inline asm" blocks, which corresponds to the
598GCC "file scope inline asm" blocks. These blocks are internally concatenated by
599LLVM and treated as a single unit, but may be separated in the .ll file if
600desired. The syntax is very simple:
601</p>
602
603<div class="doc_code"><pre>
Chris Lattner52599e12006-01-24 00:37:20 +0000[diff] [blame]604 module asm "inline asm code goes here"
605 module asm "more can go here"
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]606</pre></div>
607
608<p>The strings can contain any character by escaping non-printable characters.
609 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
610 for the number.
611</p>
612
613<p>
614 The inline asm code is simply printed to the machine code .s file when
615 assembly code is generated.
616</p>
617</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]618
619
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]620<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]621<div class="doc_section"> <a name="typesystem">Type System</a> </div>
622<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]623
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]624<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]625
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]626<p>The LLVM type system is one of the most important features of the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]627intermediate representation. Being typed enables a number of
628optimizations to be performed on the IR directly, without having to do
629extra analyses on the side before the transformation. A strong type
630system makes it easier to read the generated code and enables novel
631analyses and transformations that are not feasible to perform on normal
632three address code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]633
634</div>
635
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]636<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]637<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]638<div class="doc_text">
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]639<p>The primitive types are the fundamental building blocks of the LLVM
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]640system. The current set of primitive types is as follows:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]641
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]642<table class="layout">
643 <tr class="layout">
644 <td class="left">
645 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]646 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]647 <tr><th>Type</th><th>Description</th></tr>
648 <tr><td><tt>void</tt></td><td>No value</td></tr>
Misha Brukmancfa87bc2005-04-22 18:02:52 +0000[diff] [blame]649 <tr><td><tt>ubyte</tt></td><td>Unsigned 8-bit value</td></tr>
650 <tr><td><tt>ushort</tt></td><td>Unsigned 16-bit value</td></tr>
651 <tr><td><tt>uint</tt></td><td>Unsigned 32-bit value</td></tr>
652 <tr><td><tt>ulong</tt></td><td>Unsigned 64-bit value</td></tr>
653 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]654 <tr><td><tt>label</tt></td><td>Branch destination</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]655 </tbody>
656 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]657 </td>
658 <td class="right">
659 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]660 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]661 <tr><th>Type</th><th>Description</th></tr>
662 <tr><td><tt>bool</tt></td><td>True or False value</td></tr>
Misha Brukmancfa87bc2005-04-22 18:02:52 +0000[diff] [blame]663 <tr><td><tt>sbyte</tt></td><td>Signed 8-bit value</td></tr>
664 <tr><td><tt>short</tt></td><td>Signed 16-bit value</td></tr>
665 <tr><td><tt>int</tt></td><td>Signed 32-bit value</td></tr>
666 <tr><td><tt>long</tt></td><td>Signed 64-bit value</td></tr>
667 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]668 </tbody>
669 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]670 </td>
671 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]672</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]673</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]674
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]675<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]676<div class="doc_subsubsection"> <a name="t_classifications">Type
677Classifications</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]678<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]679<p>These different primitive types fall into a few useful
680classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]681
682<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]683 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]684 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]685 <tr>
686 <td><a name="t_signed">signed</a></td>
687 <td><tt>sbyte, short, int, long, float, double</tt></td>
688 </tr>
689 <tr>
690 <td><a name="t_unsigned">unsigned</a></td>
691 <td><tt>ubyte, ushort, uint, ulong</tt></td>
692 </tr>
693 <tr>
694 <td><a name="t_integer">integer</a></td>
695 <td><tt>ubyte, sbyte, ushort, short, uint, int, ulong, long</tt></td>
696 </tr>
697 <tr>
698 <td><a name="t_integral">integral</a></td>
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]699 <td><tt>bool, ubyte, sbyte, ushort, short, uint, int, ulong, long</tt>
700 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]701 </tr>
702 <tr>
703 <td><a name="t_floating">floating point</a></td>
704 <td><tt>float, double</tt></td>
705 </tr>
706 <tr>
707 <td><a name="t_firstclass">first class</a></td>
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]708 <td><tt>bool, ubyte, sbyte, ushort, short, uint, int, ulong, long,<br>
709 float, double, <a href="#t_pointer">pointer</a>,
710 <a href="#t_packed">packed</a></tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]711 </tr>
712 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]713</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]714
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]715<p>The <a href="#t_firstclass">first class</a> types are perhaps the
716most important. Values of these types are the only ones which can be
717produced by instructions, passed as arguments, or used as operands to
718instructions. This means that all structures and arrays must be
719manipulated either by pointer or by component.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]720</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]721
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]722<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]723<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]724
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]725<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]726
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]727<p>The real power in LLVM comes from the derived types in the system.
728This is what allows a programmer to represent arrays, functions,
729pointers, and other useful types. Note that these derived types may be
730recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]731
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]732</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]733
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]734<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]735<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]736
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]737<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]738
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]739<h5>Overview:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]740
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]741<p>The array type is a very simple derived type that arranges elements
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]742sequentially in memory. The array type requires a size (number of
743elements) and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]744
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]745<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]746
747<pre>
748 [&lt;# elements&gt; x &lt;elementtype&gt;]
749</pre>
750
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]751<p>The number of elements is a constant integer value; elementtype may
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]752be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]753
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]754<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]755<table class="layout">
756 <tr class="layout">
757 <td class="left">
758 <tt>[40 x int ]</tt><br/>
759 <tt>[41 x int ]</tt><br/>
760 <tt>[40 x uint]</tt><br/>
761 </td>
762 <td class="left">
763 Array of 40 integer values.<br/>
764 Array of 41 integer values.<br/>
765 Array of 40 unsigned integer values.<br/>
766 </td>
767 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]768</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]769<p>Here are some examples of multidimensional arrays:</p>
770<table class="layout">
771 <tr class="layout">
772 <td class="left">
773 <tt>[3 x [4 x int]]</tt><br/>
774 <tt>[12 x [10 x float]]</tt><br/>
775 <tt>[2 x [3 x [4 x uint]]]</tt><br/>
776 </td>
777 <td class="left">
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]778 3x4 array of integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]779 12x10 array of single precision floating point values.<br/>
780 2x3x4 array of unsigned integer values.<br/>
781 </td>
782 </tr>
783</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]784
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]785<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
786length array. Normally, accesses past the end of an array are undefined in
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]787LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
788As a special case, however, zero length arrays are recognized to be variable
789length. This allows implementation of 'pascal style arrays' with the LLVM
790type "{ int, [0 x float]}", for example.</p>
791
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]792</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]793
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]794<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]795<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]796<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]797<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]798<p>The function type can be thought of as a function signature. It
799consists of a return type and a list of formal parameter types.
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]800Function types are usually used to build virtual function tables
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]801(which are structures of pointers to functions), for indirect function
802calls, and when defining a function.</p>
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]803<p>
804The return type of a function type cannot be an aggregate type.
805</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]806<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]807<pre> &lt;returntype&gt; (&lt;parameter list&gt;)<br></pre>
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]808<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]809specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]810which indicates that the function takes a variable number of arguments.
811Variable argument functions can access their arguments with the <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]812 href="#int_varargs">variable argument handling intrinsic</a> functions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]813<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]814<table class="layout">
815 <tr class="layout">
816 <td class="left">
817 <tt>int (int)</tt> <br/>
818 <tt>float (int, int *) *</tt><br/>
819 <tt>int (sbyte *, ...)</tt><br/>
820 </td>
821 <td class="left">
822 function taking an <tt>int</tt>, returning an <tt>int</tt><br/>
823 <a href="#t_pointer">Pointer</a> to a function that takes an
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]824 <tt>int</tt> and a <a href="#t_pointer">pointer</a> to <tt>int</tt>,
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]825 returning <tt>float</tt>.<br/>
826 A vararg function that takes at least one <a href="#t_pointer">pointer</a>
827 to <tt>sbyte</tt> (signed char in C), which returns an integer. This is
828 the signature for <tt>printf</tt> in LLVM.<br/>
829 </td>
830 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]831</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]832
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]833</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]834<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]835<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]836<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]837<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]838<p>The structure type is used to represent a collection of data members
839together in memory. The packing of the field types is defined to match
840the ABI of the underlying processor. The elements of a structure may
841be any type that has a size.</p>
842<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
843and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
844field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
845instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]846<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]847<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]848<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]849<table class="layout">
850 <tr class="layout">
851 <td class="left">
852 <tt>{ int, int, int }</tt><br/>
853 <tt>{ float, int (int) * }</tt><br/>
854 </td>
855 <td class="left">
856 a triple of three <tt>int</tt> values<br/>
857 A pair, where the first element is a <tt>float</tt> and the second element
858 is a <a href="#t_pointer">pointer</a> to a <a href="#t_function">function</a>
859 that takes an <tt>int</tt>, returning an <tt>int</tt>.<br/>
860 </td>
861 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]862</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]863</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]864
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]865<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]866<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]867<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]868<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]869<p>As in many languages, the pointer type represents a pointer or
870reference to another object, which must live in memory.</p>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]871<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]872<pre> &lt;type&gt; *<br></pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]873<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]874<table class="layout">
875 <tr class="layout">
876 <td class="left">
877 <tt>[4x int]*</tt><br/>
878 <tt>int (int *) *</tt><br/>
879 </td>
880 <td class="left">
881 A <a href="#t_pointer">pointer</a> to <a href="#t_array">array</a> of
882 four <tt>int</tt> values<br/>
883 A <a href="#t_pointer">pointer</a> to a <a
Chris Lattnera977c482005-02-19 02:22:14 +0000[diff] [blame]884 href="#t_function">function</a> that takes an <tt>int*</tt>, returning an
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]885 <tt>int</tt>.<br/>
886 </td>
887 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]888</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]889</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]890
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]891<!-- _______________________________________________________________________ -->
892<div class="doc_subsubsection"> <a name="t_packed">Packed Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]893<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]894
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]895<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]896
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]897<p>A packed type is a simple derived type that represents a vector
898of elements. Packed types are used when multiple primitive data
899are operated in parallel using a single instruction (SIMD).
900A packed type requires a size (number of
Chris Lattnerb8d172f2005-11-10 01:44:22 +0000[diff] [blame]901elements) and an underlying primitive data type. Vectors must have a power
902of two length (1, 2, 4, 8, 16 ...). Packed types are
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]903considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]904
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]905<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]906
907<pre>
908 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
909</pre>
910
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]911<p>The number of elements is a constant integer value; elementtype may
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]912be any integral or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]913
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]914<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]915
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]916<table class="layout">
917 <tr class="layout">
918 <td class="left">
919 <tt>&lt;4 x int&gt;</tt><br/>
920 <tt>&lt;8 x float&gt;</tt><br/>
921 <tt>&lt;2 x uint&gt;</tt><br/>
922 </td>
923 <td class="left">
924 Packed vector of 4 integer values.<br/>
925 Packed vector of 8 floating-point values.<br/>
926 Packed vector of 2 unsigned integer values.<br/>
927 </td>
928 </tr>
929</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]930</div>
931
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]932<!-- _______________________________________________________________________ -->
933<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
934<div class="doc_text">
935
936<h5>Overview:</h5>
937
938<p>Opaque types are used to represent unknown types in the system. This
939corresponds (for example) to the C notion of a foward declared structure type.
940In LLVM, opaque types can eventually be resolved to any type (not just a
941structure type).</p>
942
943<h5>Syntax:</h5>
944
945<pre>
946 opaque
947</pre>
948
949<h5>Examples:</h5>
950
951<table class="layout">
952 <tr class="layout">
953 <td class="left">
954 <tt>opaque</tt>
955 </td>
956 <td class="left">
957 An opaque type.<br/>
958 </td>
959 </tr>
960</table>
961</div>
962
963
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]964<!-- *********************************************************************** -->
965<div class="doc_section"> <a name="constants">Constants</a> </div>
966<!-- *********************************************************************** -->
967
968<div class="doc_text">
969
970<p>LLVM has several different basic types of constants. This section describes
971them all and their syntax.</p>
972
973</div>
974
975<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]976<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]977
978<div class="doc_text">
979
980<dl>
981 <dt><b>Boolean constants</b></dt>
982
983 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
984 constants of the <tt><a href="#t_primitive">bool</a></tt> type.
985 </dd>
986
987 <dt><b>Integer constants</b></dt>
988
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]989 <dd>Standard integers (such as '4') are constants of the <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]990 href="#t_integer">integer</a> type. Negative numbers may be used with signed
991 integer types.
992 </dd>
993
994 <dt><b>Floating point constants</b></dt>
995
996 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
997 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]998 notation (see below). Floating point constants must have a <a
999 href="#t_floating">floating point</a> type. </dd>
1000
1001 <dt><b>Null pointer constants</b></dt>
1002
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1003 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1004 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1005
1006</dl>
1007
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1008<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1009of floating point constants. For example, the form '<tt>double
10100x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
10114.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1012(and the only time that they are generated by the disassembler) is when a
1013floating point constant must be emitted but it cannot be represented as a
1014decimal floating point number. For example, NaN's, infinities, and other
1015special values are represented in their IEEE hexadecimal format so that
1016assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1017
1018</div>
1019
1020<!-- ======================================================================= -->
1021<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1022</div>
1023
1024<div class="doc_text">
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1025<p>Aggregate constants arise from aggregation of simple constants
1026and smaller aggregate constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1027
1028<dl>
1029 <dt><b>Structure constants</b></dt>
1030
1031 <dd>Structure constants are represented with notation similar to structure
1032 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1033 (<tt>{}</tt>)). For example: "<tt>{ int 4, float 17.0, int* %G }</tt>",
1034 where "<tt>%G</tt>" is declared as "<tt>%G = external global int</tt>". Structure constants
1035 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1036 types of elements must match those specified by the type.
1037 </dd>
1038
1039 <dt><b>Array constants</b></dt>
1040
1041 <dd>Array constants are represented with notation similar to array type
1042 definitions (a comma separated list of elements, surrounded by square brackets
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1043 (<tt>[]</tt>)). For example: "<tt>[ int 42, int 11, int 74 ]</tt>". Array
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1044 constants must have <a href="#t_array">array type</a>, and the number and
1045 types of elements must match those specified by the type.
1046 </dd>
1047
1048 <dt><b>Packed constants</b></dt>
1049
1050 <dd>Packed constants are represented with notation similar to packed type
1051 definitions (a comma separated list of elements, surrounded by
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1052 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; int 42,
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1053 int 11, int 74, int 100 &gt;</tt>". Packed constants must have <a
1054 href="#t_packed">packed type</a>, and the number and types of elements must
1055 match those specified by the type.
1056 </dd>
1057
1058 <dt><b>Zero initialization</b></dt>
1059
1060 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1061 value to zero of <em>any</em> type, including scalar and aggregate types.
1062 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]1063 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1064 initializers.
1065 </dd>
1066</dl>
1067
1068</div>
1069
1070<!-- ======================================================================= -->
1071<div class="doc_subsection">
1072 <a name="globalconstants">Global Variable and Function Addresses</a>
1073</div>
1074
1075<div class="doc_text">
1076
1077<p>The addresses of <a href="#globalvars">global variables</a> and <a
1078href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1079constants. These constants are explicitly referenced when the <a
1080href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1081href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1082file:</p>
1083
1084<pre>
1085 %X = global int 17
1086 %Y = global int 42
1087 %Z = global [2 x int*] [ int* %X, int* %Y ]
1088</pre>
1089
1090</div>
1091
1092<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1093<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1094<div class="doc_text">
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1095 <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]1096 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1097 a constant is permitted.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1098
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1099 <p>Undefined values indicate to the compiler that the program is well defined
1100 no matter what value is used, giving the compiler more freedom to optimize.
1101 </p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1102</div>
1103
1104<!-- ======================================================================= -->
1105<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1106</div>
1107
1108<div class="doc_text">
1109
1110<p>Constant expressions are used to allow expressions involving other constants
1111to be used as constants. Constant expressions may be of any <a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1112href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1113that does not have side effects (e.g. load and call are not supported). The
1114following is the syntax for constant expressions:</p>
1115
1116<dl>
1117 <dt><b><tt>cast ( CST to TYPE )</tt></b></dt>
1118
1119 <dd>Cast a constant to another type.</dd>
1120
1121 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1122
1123 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1124 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1125 instruction, the index list may have zero or more indexes, which are required
1126 to make sense for the type of "CSTPTR".</dd>
1127
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1128 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1129
1130 <dd>Perform the <a href="#i_select">select operation</a> on
1131 constants.
1132
1133 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1134
1135 <dd>Perform the <a href="#i_extractelement">extractelement
1136 operation</a> on constants.
1137
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1138 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1139
1140 <dd>Perform the <a href="#i_insertelement">insertelement
1141 operation</a> on constants.
1142
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1143
1144 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1145
1146 <dd>Perform the <a href="#i_shufflevector">shufflevector
1147 operation</a> on constants.
1148
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1149 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1150
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1151 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1152 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1153 binary</a> operations. The constraints on operands are the same as those for
1154 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1155 values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1156</dl>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1157</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]1158
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1159<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1160<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1161<!-- *********************************************************************** -->
1162
1163<!-- ======================================================================= -->
1164<div class="doc_subsection">
1165<a name="inlineasm">Inline Assembler Expressions</a>
1166</div>
1167
1168<div class="doc_text">
1169
1170<p>
1171LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1172Module-Level Inline Assembly</a>) through the use of a special value. This
1173value represents the inline assembler as a string (containing the instructions
1174to emit), a list of operand constraints (stored as a string), and a flag that
1175indicates whether or not the inline asm expression has side effects. An example
1176inline assembler expression is:
1177</p>
1178
1179<pre>
1180 int(int) asm "bswap $0", "=r,r"
1181</pre>
1182
1183<p>
1184Inline assembler expressions may <b>only</b> be used as the callee operand of
1185a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1186</p>
1187
1188<pre>
1189 %X = call int asm "<a href="#i_bswap">bswap</a> $0", "=r,r"(int %Y)
1190</pre>
1191
1192<p>
1193Inline asms with side effects not visible in the constraint list must be marked
1194as having side effects. This is done through the use of the
1195'<tt>sideeffect</tt>' keyword, like so:
1196</p>
1197
1198<pre>
1199 call void asm sideeffect "eieio", ""()
1200</pre>
1201
1202<p>TODO: The format of the asm and constraints string still need to be
1203documented here. Constraints on what can be done (e.g. duplication, moving, etc
1204need to be documented).
1205</p>
1206
1207</div>
1208
1209<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1210<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1211<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1212
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1213<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1214
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1215<p>The LLVM instruction set consists of several different
1216classifications of instructions: <a href="#terminators">terminator
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1217instructions</a>, <a href="#binaryops">binary instructions</a>,
1218<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1219 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1220instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1221
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1222</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1223
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1224<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1225<div class="doc_subsection"> <a name="terminators">Terminator
1226Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1227
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1228<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1229
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1230<p>As mentioned <a href="#functionstructure">previously</a>, every
1231basic block in a program ends with a "Terminator" instruction, which
1232indicates which block should be executed after the current block is
1233finished. These terminator instructions typically yield a '<tt>void</tt>'
1234value: they produce control flow, not values (the one exception being
1235the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1236<p>There are six different terminator instructions: the '<a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1237 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1238instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1239the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1240 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1241 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1242
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1243</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1244
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1245<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1246<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1247Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1248<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1249<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1250<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]1251 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1252</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1253<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1254<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1255value) from a function back to the caller.</p>
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]1256<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1257returns a value and then causes control flow, and one that just causes
1258control flow to occur.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1259<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1260<p>The '<tt>ret</tt>' instruction may return any '<a
1261 href="#t_firstclass">first class</a>' type. Notice that a function is
1262not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
1263instruction inside of the function that returns a value that does not
1264match the return type of the function.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1265<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1266<p>When the '<tt>ret</tt>' instruction is executed, control flow
1267returns back to the calling function's context. If the caller is a "<a
John Criswellfa081872004-06-25 15:16:57 +0000[diff] [blame]1268 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1269the instruction after the call. If the caller was an "<a
1270 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1271at the beginning of the "normal" destination block. If the instruction
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1272returns a value, that value shall set the call or invoke instruction's
1273return value.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1274<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1275<pre> ret int 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1276 ret void <i>; Return from a void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1277</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1278</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1279<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1280<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1281<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1282<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1283<pre> br bool &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]1284</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1285<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1286<p>The '<tt>br</tt>' instruction is used to cause control flow to
1287transfer to a different basic block in the current function. There are
1288two forms of this instruction, corresponding to a conditional branch
1289and an unconditional branch.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1290<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1291<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
1292single '<tt>bool</tt>' value and two '<tt>label</tt>' values. The
1293unconditional form of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>'
1294value as a target.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1295<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1296<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>bool</tt>'
1297argument is evaluated. If the value is <tt>true</tt>, control flows
1298to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1299control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1300<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1301<pre>Test:<br> %cond = <a href="#i_setcc">seteq</a> int %a, %b<br> br bool %cond, label %IfEqual, label %IfUnequal<br>IfEqual:<br> <a
1302 href="#i_ret">ret</a> int 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> int 0<br></pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1303</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1304<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1305<div class="doc_subsubsection">
1306 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1307</div>
1308
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1309<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1310<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1311
1312<pre>
1313 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1314</pre>
1315
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1316<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1317
1318<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1319several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1320instruction, allowing a branch to occur to one of many possible
1321destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1322
1323
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1324<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1325
1326<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1327comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1328an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1329table is not allowed to contain duplicate constant entries.</p>
1330
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1331<h5>Semantics:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1332
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1333<p>The <tt>switch</tt> instruction specifies a table of values and
1334destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1335table is searched for the given value. If the value is found, control flow is
1336transfered to the corresponding destination; otherwise, control flow is
1337transfered to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1338
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1339<h5>Implementation:</h5>
1340
1341<p>Depending on properties of the target machine and the particular
1342<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1343ways. For example, it could be generated as a series of chained conditional
1344branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1345
1346<h5>Example:</h5>
1347
1348<pre>
1349 <i>; Emulate a conditional br instruction</i>
1350 %Val = <a href="#i_cast">cast</a> bool %value to int
1351 switch int %Val, label %truedest [int 0, label %falsedest ]
1352
1353 <i>; Emulate an unconditional br instruction</i>
1354 switch uint 0, label %dest [ ]
1355
1356 <i>; Implement a jump table:</i>
1357 switch uint %val, label %otherwise [ uint 0, label %onzero
1358 uint 1, label %onone
1359 uint 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1360</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1361</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1362
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1363<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1364<div class="doc_subsubsection">
1365 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1366</div>
1367
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1368<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1369
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1370<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1371
1372<pre>
1373 &lt;result&gt; = invoke [<a href="#callingconv">cconv</a>] &lt;ptr to function ty&gt; %&lt;function ptr val&gt;(&lt;function args&gt;)
1374 to label &lt;normal label&gt; except label &lt;exception label&gt;
1375</pre>
1376
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1377<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1378
1379<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1380function, with the possibility of control flow transfer to either the
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1381'<tt>normal</tt>' label or the
1382'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1383"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1384"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1385href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
1386continued at the dynamically nearest "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1387
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1388<h5>Arguments:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1389
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1390<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1391
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1392<ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1393 <li>
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1394 The optional "cconv" marker indicates which <a href="callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1395 convention</a> the call should use. If none is specified, the call defaults
1396 to using C calling conventions.
1397 </li>
1398 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1399 function value being invoked. In most cases, this is a direct function
1400 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1401 an arbitrary pointer to function value.
1402 </li>
1403
1404 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1405 function to be invoked. </li>
1406
1407 <li>'<tt>function args</tt>': argument list whose types match the function
1408 signature argument types. If the function signature indicates the function
1409 accepts a variable number of arguments, the extra arguments can be
1410 specified. </li>
1411
1412 <li>'<tt>normal label</tt>': the label reached when the called function
1413 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1414
1415 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1416 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1417
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1418</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1419
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1420<h5>Semantics:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1421
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1422<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1423href="#i_call">call</a></tt>' instruction in most regards. The primary
1424difference is that it establishes an association with a label, which is used by
1425the runtime library to unwind the stack.</p>
1426
1427<p>This instruction is used in languages with destructors to ensure that proper
1428cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1429exception. Additionally, this is important for implementation of
1430'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1431
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1432<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1433<pre>
1434 %retval = invoke int %Test(int 15) to label %Continue
1435 except label %TestCleanup <i>; {int}:retval set</i>
1436 %retval = invoke <a href="#callingconv">coldcc</a> int %Test(int 15) to label %Continue
1437 except label %TestCleanup <i>; {int}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1438</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1439</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1440
1441
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1442<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1443
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1444<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1445Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1446
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1447<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1448
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1449<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1450<pre>
1451 unwind
1452</pre>
1453
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1454<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1455
1456<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
1457at the first callee in the dynamic call stack which used an <a
1458href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
1459primarily used to implement exception handling.</p>
1460
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1461<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1462
1463<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
1464immediately halt. The dynamic call stack is then searched for the first <a
1465href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
1466execution continues at the "exceptional" destination block specified by the
1467<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
1468dynamic call chain, undefined behavior results.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1469</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1470
1471<!-- _______________________________________________________________________ -->
1472
1473<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
1474Instruction</a> </div>
1475
1476<div class="doc_text">
1477
1478<h5>Syntax:</h5>
1479<pre>
1480 unreachable
1481</pre>
1482
1483<h5>Overview:</h5>
1484
1485<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
1486instruction is used to inform the optimizer that a particular portion of the
1487code is not reachable. This can be used to indicate that the code after a
1488no-return function cannot be reached, and other facts.</p>
1489
1490<h5>Semantics:</h5>
1491
1492<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
1493</div>
1494
1495
1496
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1497<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1498<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1499<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1500<p>Binary operators are used to do most of the computation in a
1501program. They require two operands, execute an operation on them, and
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1502produce a single value. The operands might represent
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1503multiple data, as is the case with the <a href="#t_packed">packed</a> data type.
1504The result value of a binary operator is not
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1505necessarily the same type as its operands.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1506<p>There are several different binary operators:</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1507</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1508<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1509<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
1510Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1511<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1512<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1513<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]1514</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1515<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1516<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1517<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1518<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1519 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
1520 This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1521Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1522<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1523<p>The value produced is the integer or floating point sum of the two
1524operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1525<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1526<pre> &lt;result&gt; = add int 4, %var <i>; yields {int}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1527</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1528</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1529<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1530<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
1531Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1532<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1533<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1534<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]1535</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1536<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1537<p>The '<tt>sub</tt>' instruction returns the difference of its two
1538operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1539<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
1540instruction present in most other intermediate representations.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1541<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1542<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1543 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1544values.
1545This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1546Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1547<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1548<p>The value produced is the integer or floating point difference of
1549the two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1550<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1551<pre> &lt;result&gt; = sub int 4, %var <i>; yields {int}:result = 4 - %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1552 &lt;result&gt; = sub int 0, %val <i>; yields {int}:result = -%var</i>
1553</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1554</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1555<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1556<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
1557Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1558<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1559<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1560<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]1561</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1562<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1563<p>The '<tt>mul</tt>' instruction returns the product of its two
1564operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1565<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1566<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1567 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1568values.
1569This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1570Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1571<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1572<p>The value produced is the integer or floating point product of the
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1573two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1574<p>There is no signed vs unsigned multiplication. The appropriate
1575action is taken based on the type of the operand.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1576<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1577<pre> &lt;result&gt; = mul int 4, %var <i>; yields {int}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1578</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1579</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1580<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1581<div class="doc_subsubsection"> <a name="i_div">'<tt>div</tt>'
1582Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1583<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1584<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1585<pre> &lt;result&gt; = div &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1586</pre>
1587<h5>Overview:</h5>
1588<p>The '<tt>div</tt>' instruction returns the quotient of its two
1589operands.</p>
1590<h5>Arguments:</h5>
1591<p>The two arguments to the '<tt>div</tt>' instruction must be either <a
1592 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1593values.
1594This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1595Both arguments must have identical types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1596<h5>Semantics:</h5>
1597<p>The value produced is the integer or floating point quotient of the
1598two operands.</p>
1599<h5>Example:</h5>
1600<pre> &lt;result&gt; = div int 4, %var <i>; yields {int}:result = 4 / %var</i>
1601</pre>
1602</div>
1603<!-- _______________________________________________________________________ -->
1604<div class="doc_subsubsection"> <a name="i_rem">'<tt>rem</tt>'
1605Instruction</a> </div>
1606<div class="doc_text">
1607<h5>Syntax:</h5>
1608<pre> &lt;result&gt; = rem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1609</pre>
1610<h5>Overview:</h5>
1611<p>The '<tt>rem</tt>' instruction returns the remainder from the
1612division of its two operands.</p>
1613<h5>Arguments:</h5>
1614<p>The two arguments to the '<tt>rem</tt>' instruction must be either <a
1615 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1616values.
1617This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1618Both arguments must have identical types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1619<h5>Semantics:</h5>
1620<p>This returns the <i>remainder</i> of a division (where the result
1621has the same sign as the divisor), not the <i>modulus</i> (where the
1622result has the same sign as the dividend) of a value. For more
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1623information about the difference, see <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1624 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
1625Math Forum</a>.</p>
1626<h5>Example:</h5>
1627<pre> &lt;result&gt; = rem int 4, %var <i>; yields {int}:result = 4 % %var</i>
1628</pre>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]1629
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1630</div>
1631<!-- _______________________________________________________________________ -->
1632<div class="doc_subsubsection"> <a name="i_setcc">'<tt>set<i>cc</i></tt>'
1633Instructions</a> </div>
1634<div class="doc_text">
1635<h5>Syntax:</h5>
1636<pre> &lt;result&gt; = seteq &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1637 &lt;result&gt; = setne &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1638 &lt;result&gt; = setlt &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1639 &lt;result&gt; = setgt &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1640 &lt;result&gt; = setle &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1641 &lt;result&gt; = setge &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1642</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1643<h5>Overview:</h5>
1644<p>The '<tt>set<i>cc</i></tt>' family of instructions returns a boolean
1645value based on a comparison of their two operands.</p>
1646<h5>Arguments:</h5>
1647<p>The two arguments to the '<tt>set<i>cc</i></tt>' instructions must
1648be of <a href="#t_firstclass">first class</a> type (it is not possible
1649to compare '<tt>label</tt>'s, '<tt>array</tt>'s, '<tt>structure</tt>'
1650or '<tt>void</tt>' values, etc...). Both arguments must have identical
1651types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1652<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1653<p>The '<tt>seteq</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1654value if both operands are equal.<br>
1655The '<tt>setne</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1656value if both operands are unequal.<br>
1657The '<tt>setlt</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1658value if the first operand is less than the second operand.<br>
1659The '<tt>setgt</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1660value if the first operand is greater than the second operand.<br>
1661The '<tt>setle</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1662value if the first operand is less than or equal to the second operand.<br>
1663The '<tt>setge</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1664value if the first operand is greater than or equal to the second
1665operand.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1666<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1667<pre> &lt;result&gt; = seteq int 4, 5 <i>; yields {bool}:result = false</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1668 &lt;result&gt; = setne float 4, 5 <i>; yields {bool}:result = true</i>
1669 &lt;result&gt; = setlt uint 4, 5 <i>; yields {bool}:result = true</i>
1670 &lt;result&gt; = setgt sbyte 4, 5 <i>; yields {bool}:result = false</i>
1671 &lt;result&gt; = setle sbyte 4, 5 <i>; yields {bool}:result = true</i>
1672 &lt;result&gt; = setge sbyte 4, 5 <i>; yields {bool}:result = false</i>
1673</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1674</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]1675
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1676<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1677<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
1678Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1679<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1680<p>Bitwise binary operators are used to do various forms of
1681bit-twiddling in a program. They are generally very efficient
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1682instructions and can commonly be strength reduced from other
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1683instructions. They require two operands, execute an operation on them,
1684and produce a single value. The resulting value of the bitwise binary
1685operators is always the same type as its first operand.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1686</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1687<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1688<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
1689Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1690<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1691<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1692<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]1693</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1694<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1695<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
1696its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1697<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1698<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1699 href="#t_integral">integral</a> values. Both arguments must have
1700identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1701<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1702<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1703<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1704<div style="align: center">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1705<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1706 <tbody>
1707 <tr>
1708 <td>In0</td>
1709 <td>In1</td>
1710 <td>Out</td>
1711 </tr>
1712 <tr>
1713 <td>0</td>
1714 <td>0</td>
1715 <td>0</td>
1716 </tr>
1717 <tr>
1718 <td>0</td>
1719 <td>1</td>
1720 <td>0</td>
1721 </tr>
1722 <tr>
1723 <td>1</td>
1724 <td>0</td>
1725 <td>0</td>
1726 </tr>
1727 <tr>
1728 <td>1</td>
1729 <td>1</td>
1730 <td>1</td>
1731 </tr>
1732 </tbody>
1733</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1734</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1735<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1736<pre> &lt;result&gt; = and int 4, %var <i>; yields {int}:result = 4 &amp; %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1737 &lt;result&gt; = and int 15, 40 <i>; yields {int}:result = 8</i>
1738 &lt;result&gt; = and int 4, 8 <i>; yields {int}:result = 0</i>
1739</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1740</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1741<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1742<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1743<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1744<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1745<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]1746</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1747<h5>Overview:</h5>
1748<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
1749or of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1750<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1751<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1752 href="#t_integral">integral</a> values. Both arguments must have
1753identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1754<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1755<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1756<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1757<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1758<table border="1" cellspacing="0" cellpadding="4">
1759 <tbody>
1760 <tr>
1761 <td>In0</td>
1762 <td>In1</td>
1763 <td>Out</td>
1764 </tr>
1765 <tr>
1766 <td>0</td>
1767 <td>0</td>
1768 <td>0</td>
1769 </tr>
1770 <tr>
1771 <td>0</td>
1772 <td>1</td>
1773 <td>1</td>
1774 </tr>
1775 <tr>
1776 <td>1</td>
1777 <td>0</td>
1778 <td>1</td>
1779 </tr>
1780 <tr>
1781 <td>1</td>
1782 <td>1</td>
1783 <td>1</td>
1784 </tr>
1785 </tbody>
1786</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1787</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1788<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1789<pre> &lt;result&gt; = or int 4, %var <i>; yields {int}:result = 4 | %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1790 &lt;result&gt; = or int 15, 40 <i>; yields {int}:result = 47</i>
1791 &lt;result&gt; = or int 4, 8 <i>; yields {int}:result = 12</i>
1792</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1793</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1794<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1795<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
1796Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1797<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1798<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1799<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]1800</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1801<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1802<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
1803or of its two operands. The <tt>xor</tt> is used to implement the
1804"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1805<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1806<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1807 href="#t_integral">integral</a> values. Both arguments must have
1808identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1809<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1810<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1811<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1812<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1813<table border="1" cellspacing="0" cellpadding="4">
1814 <tbody>
1815 <tr>
1816 <td>In0</td>
1817 <td>In1</td>
1818 <td>Out</td>
1819 </tr>
1820 <tr>
1821 <td>0</td>
1822 <td>0</td>
1823 <td>0</td>
1824 </tr>
1825 <tr>
1826 <td>0</td>
1827 <td>1</td>
1828 <td>1</td>
1829 </tr>
1830 <tr>
1831 <td>1</td>
1832 <td>0</td>
1833 <td>1</td>
1834 </tr>
1835 <tr>
1836 <td>1</td>
1837 <td>1</td>
1838 <td>0</td>
1839 </tr>
1840 </tbody>
1841</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1842</div>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1843<p> </p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1844<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1845<pre> &lt;result&gt; = xor int 4, %var <i>; yields {int}:result = 4 ^ %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1846 &lt;result&gt; = xor int 15, 40 <i>; yields {int}:result = 39</i>
1847 &lt;result&gt; = xor int 4, 8 <i>; yields {int}:result = 12</i>
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1848 &lt;result&gt; = xor int %V, -1 <i>; yields {int}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1849</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1850</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1851<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1852<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
1853Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1854<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1855<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1856<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, ubyte &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1857</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1858<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1859<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
1860the left a specified number of bits.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1861<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1862<p>The first argument to the '<tt>shl</tt>' instruction must be an <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1863 href="#t_integer">integer</a> type. The second argument must be an '<tt>ubyte</tt>'
1864type.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1865<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1866<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1867<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1868<pre> &lt;result&gt; = shl int 4, ubyte %var <i>; yields {int}:result = 4 &lt;&lt; %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1869 &lt;result&gt; = shl int 4, ubyte 2 <i>; yields {int}:result = 16</i>
1870 &lt;result&gt; = shl int 1, ubyte 10 <i>; yields {int}:result = 1024</i>
1871</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1872</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1873<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1874<div class="doc_subsubsection"> <a name="i_shr">'<tt>shr</tt>'
1875Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1876<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1877<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1878<pre> &lt;result&gt; = shr &lt;ty&gt; &lt;var1&gt;, ubyte &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1879</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1880<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1881<p>The '<tt>shr</tt>' instruction returns the first operand shifted to
1882the right a specified number of bits.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1883<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1884<p>The first argument to the '<tt>shr</tt>' instruction must be an <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1885 href="#t_integer">integer</a> type. The second argument must be an '<tt>ubyte</tt>'
1886type.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1887<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1888<p>If the first argument is a <a href="#t_signed">signed</a> type, the
1889most significant bit is duplicated in the newly free'd bit positions.
1890If the first argument is unsigned, zero bits shall fill the empty
1891positions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1892<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1893<pre> &lt;result&gt; = shr int 4, ubyte %var <i>; yields {int}:result = 4 &gt;&gt; %var</i>
Chris Lattner8c6bb902003-06-18 21:30:51 +0000[diff] [blame]1894 &lt;result&gt; = shr uint 4, ubyte 1 <i>; yields {uint}:result = 2</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1895 &lt;result&gt; = shr int 4, ubyte 2 <i>; yields {int}:result = 1</i>
Chris Lattner8c6bb902003-06-18 21:30:51 +0000[diff] [blame]1896 &lt;result&gt; = shr sbyte 4, ubyte 3 <i>; yields {sbyte}:result = 0</i>
1897 &lt;result&gt; = shr sbyte -2, ubyte 1 <i>; yields {sbyte}:result = -1</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1898</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1899</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]1900
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1901<!-- ======================================================================= -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]1902<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]1903 <a name="vectorops">Vector Operations</a>
1904</div>
1905
1906<div class="doc_text">
1907
1908<p>LLVM supports several instructions to represent vector operations in a
1909target-independent manner. This instructions cover the element-access and
1910vector-specific operations needed to process vectors effectively. While LLVM
1911does directly support these vector operations, many sophisticated algorithms
1912will want to use target-specific intrinsics to take full advantage of a specific
1913target.</p>
1914
1915</div>
1916
1917<!-- _______________________________________________________________________ -->
1918<div class="doc_subsubsection">
1919 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
1920</div>
1921
1922<div class="doc_text">
1923
1924<h5>Syntax:</h5>
1925
1926<pre>
1927 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, uint &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
1928</pre>
1929
1930<h5>Overview:</h5>
1931
1932<p>
1933The '<tt>extractelement</tt>' instruction extracts a single scalar
1934element from a packed vector at a specified index.
1935</p>
1936
1937
1938<h5>Arguments:</h5>
1939
1940<p>
1941The first operand of an '<tt>extractelement</tt>' instruction is a
1942value of <a href="#t_packed">packed</a> type. The second operand is
1943an index indicating the position from which to extract the element.
1944The index may be a variable.</p>
1945
1946<h5>Semantics:</h5>
1947
1948<p>
1949The result is a scalar of the same type as the element type of
1950<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
1951<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
1952results are undefined.
1953</p>
1954
1955<h5>Example:</h5>
1956
1957<pre>
1958 %result = extractelement &lt;4 x int&gt; %vec, uint 0 <i>; yields int</i>
1959</pre>
1960</div>
1961
1962
1963<!-- _______________________________________________________________________ -->
1964<div class="doc_subsubsection">
1965 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
1966</div>
1967
1968<div class="doc_text">
1969
1970<h5>Syntax:</h5>
1971
1972<pre>
1973 &lt;result&gt; = insertelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, &lt;ty&gt; &lt;elt&gt, uint &lt;idx&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
1974</pre>
1975
1976<h5>Overview:</h5>
1977
1978<p>
1979The '<tt>insertelement</tt>' instruction inserts a scalar
1980element into a packed vector at a specified index.
1981</p>
1982
1983
1984<h5>Arguments:</h5>
1985
1986<p>
1987The first operand of an '<tt>insertelement</tt>' instruction is a
1988value of <a href="#t_packed">packed</a> type. The second operand is a
1989scalar value whose type must equal the element type of the first
1990operand. The third operand is an index indicating the position at
1991which to insert the value. The index may be a variable.</p>
1992
1993<h5>Semantics:</h5>
1994
1995<p>
1996The result is a packed vector of the same type as <tt>val</tt>. Its
1997element values are those of <tt>val</tt> except at position
1998<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
1999exceeds the length of <tt>val</tt>, the results are undefined.
2000</p>
2001
2002<h5>Example:</h5>
2003
2004<pre>
2005 %result = insertelement &lt;4 x int&gt; %vec, int 1, uint 0 <i>; yields &lt;4 x int&gt;</i>
2006</pre>
2007</div>
2008
2009<!-- _______________________________________________________________________ -->
2010<div class="doc_subsubsection">
2011 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2012</div>
2013
2014<div class="doc_text">
2015
2016<h5>Syntax:</h5>
2017
2018<pre>
2019 &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 uint&gt; &lt;mask&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
2020</pre>
2021
2022<h5>Overview:</h5>
2023
2024<p>
2025The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2026from two input vectors, returning a vector of the same type.
2027</p>
2028
2029<h5>Arguments:</h5>
2030
2031<p>
2032The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2033with types that match each other and types that match the result of the
2034instruction. The third argument is a shuffle mask, which has the same number
2035of elements as the other vector type, but whose element type is always 'uint'.
2036</p>
2037
2038<p>
2039The shuffle mask operand is required to be a constant vector with either
2040constant integer or undef values.
2041</p>
2042
2043<h5>Semantics:</h5>
2044
2045<p>
2046The elements of the two input vectors are numbered from left to right across
2047both of the vectors. The shuffle mask operand specifies, for each element of
2048the result vector, which element of the two input registers the result element
2049gets. The element selector may be undef (meaning "don't care") and the second
2050operand may be undef if performing a shuffle from only one vector.
2051</p>
2052
2053<h5>Example:</h5>
2054
2055<pre>
2056 %result = shufflevector &lt;4 x int&gt; %v1, &lt;4 x int&gt; %v2,
2057 &lt;4 x uint&gt; &lt;uint 0, uint 4, uint 1, uint 5&gt; <i>; yields &lt;4 x int&gt;</i>
2058 %result = shufflevector &lt;4 x int&gt; %v1, &lt;4 x int&gt; undef,
2059 &lt;4 x uint&gt; &lt;uint 0, uint 1, uint 2, uint 3&gt; <i>; yields &lt;4 x int&gt;</i> - Identity shuffle.
2060</pre>
2061</div>
2062
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]2063
2064<!-- _______________________________________________________________________ -->
2065<div class="doc_subsubsection"> <a name="i_vsetint">'<tt>vsetint</tt>'
2066Instruction</a> </div>
2067<div class="doc_text">
2068<h5>Syntax:</h5>
2069<pre>&lt;result&gt; = vsetint &lt;op&gt;, &lt;n x &lt;ty&gt;&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields &lt;n x bool&gt;</i>
2070</pre>
2071
2072<h5>Overview:</h5>
2073
2074<p>The '<tt>vsetint</tt>' instruction takes two integer vectors and
2075returns a vector of boolean values representing, at each position, the
2076result of the comparison between the values at that position in the
2077two operands.</p>
2078
2079<h5>Arguments:</h5>
2080
2081<p>The arguments to a '<tt>vsetint</tt>' instruction are a comparison
2082operation and two value arguments. The value arguments must be of <a
2083href="#t_integral">integral</a> <a href="#t_packed">packed</a> type,
2084and they must have identical types. The operation argument must be
2085one of <tt>eq</tt>, <tt>ne</tt>, <tt>slt</tt>, <tt>sgt</tt>,
2086<tt>sle</tt>, <tt>sge</tt>, <tt>ult</tt>, <tt>ugt</tt>, <tt>ule</tt>,
2087<tt>uge</tt>, <tt>true</tt>, and <tt>false</tt>. The result is a
2088packed <tt>bool</tt> value with the same length as each operand.</p>
2089
2090<h5>Semantics:</h5>
2091
2092<p>The following table shows the semantics of '<tt>vsetint</tt>'. For
2093each position of the result, the comparison is done on the
2094corresponding positions of the two value arguments. Note that the
2095signedness of the comparison depends on the comparison opcode and
2096<i>not</i> on the signedness of the value operands. E.g., <tt>vsetint
2097slt <4 x unsigned> %x, %y</tt> does an elementwise <i>signed</i>
2098comparison of <tt>%x</tt> and <tt>%y</tt>.</p>
2099
2100<table border="1" cellspacing="0" cellpadding="4">
2101 <tbody>
2102 <tr><th>Operation</th><th>Result is true iff</th><th>Comparison is</th></tr>
2103 <tr><td><tt>eq</tt></td><td>var1 == var2</td><td>--</td></tr>
2104 <tr><td><tt>ne</tt></td><td>var1 != var2</td><td>--</td></tr>
2105 <tr><td><tt>slt</tt></td><td>var1 &lt; var2</td><td>signed</td></tr>
2106 <tr><td><tt>sgt</tt></td><td>var1 &gt; var2</td><td>signed</td></tr>
2107 <tr><td><tt>sle</tt></td><td>var1 &lt;= var2</td><td>signed</td></tr>
2108 <tr><td><tt>sge</tt></td><td>var1 &gt;= var2</td><td>signed</td></tr>
2109 <tr><td><tt>ult</tt></td><td>var1 &lt; var2</td><td>unsigned</td></tr>
2110 <tr><td><tt>ugt</tt></td><td>var1 &gt; var2</td><td>unsigned</td></tr>
2111 <tr><td><tt>ule</tt></td><td>var1 &lt;= var2</td><td>unsigned</td></tr>
2112 <tr><td><tt>uge</tt></td><td>var1 &gt;= var2</td><td>unsigned</td></tr>
2113 <tr><td><tt>true</tt></td><td>always</td><td>--</td></tr>
2114 <tr><td><tt>false</tt></td><td>never</td><td>--</td></tr>
2115 </tbody>
2116</table>
2117
2118<h5>Example:</h5>
2119<pre> &lt;result&gt; = vsetint eq &lt;2 x int&gt; &lt;int 0, int 1&gt;, &lt;int 1, int 0&gt; <i>; yields {&lt;2 x bool&gt;}:result = false, false</i>
2120 &lt;result&gt; = vsetint ne &lt;2 x int&gt; &lt;int 0, int 1&gt;, &lt;int 1, int 0&gt; <i>; yields {&lt;2 x bool&gt;}:result = true, true</i>
2121 &lt;result&gt; = vsetint slt &lt;2 x int&gt; &lt;int 0, int 1&gt;, &lt;int 1, int 0&gt; <i>; yields {&lt;2 x bool&gt;}:result = true, false</i>
2122 &lt;result&gt; = vsetint sgt &lt;2 x int&gt; &lt;int 0, int 1&gt;, &lt;int 1, int 0&gt; <i>; yields {&lt;2 x bool&gt;}:result = false, true</i>
2123 &lt;result&gt; = vsetint sle &lt;2 x int&gt; &lt;int 0, int 1&gt;, &lt;int 1, int 0&gt; <i>; yields {&lt;2 x bool&gt;}:result = true, false</i>
2124 &lt;result&gt; = vsetint sge &lt;2 x int&gt; &lt;int 0, int 1&gt;, &lt;int 1, int 0&gt; <i>; yields {&lt;2 x bool&gt;}:result = false, true</i>
2125</pre>
2126</div>
2127
2128<!-- _______________________________________________________________________ -->
2129<div class="doc_subsubsection"> <a name="i_vsetfp">'<tt>vsetfp</tt>'
2130Instruction</a> </div>
2131<div class="doc_text">
2132<h5>Syntax:</h5>
2133<pre>&lt;result&gt; = vsetfp &lt;op&gt;, &lt;n x &lt;ty&gt;&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields &lt;n x bool&gt;</i>
2134</pre>
2135
2136<h5>Overview:</h5>
2137
2138<p>The '<tt>vsetfp</tt>' instruction takes two floating point vector
2139arguments and returns a vector of boolean values representing, at each
2140position, the result of the comparison between the values at that
2141position in the two operands.</p>
2142
2143<h5>Arguments:</h5>
2144
2145<p>The arguments to a '<tt>vsetfp</tt>' instruction are a comparison
2146operation and two value arguments. The value arguments must be of <a
2147href="t_floating">floating point</a> <a href="#t_packed">packed</a>
2148type, and they must have identical types. The operation argument must
2149be one of <tt>eq</tt>, <tt>ne</tt>, <tt>lt</tt>, <tt>gt</tt>,
2150<tt>le</tt>, <tt>ge</tt>, <tt>oeq</tt>, <tt>one</tt>, <tt>olt</tt>,
2151<tt>ogt</tt>, <tt>ole</tt>, <tt>oge</tt>, <tt>ueq</tt>, <tt>une</tt>,
2152<tt>ult</tt>, <tt>ugt</tt>, <tt>ule</tt>, <tt>uge</tt>, <tt>o</tt>,
2153<tt>u</tt>, <tt>true</tt>, and <tt>false</tt>. The result is a packed
2154<tt>bool</tt> value with the same length as each operand.</p>
2155
2156<h5>Semantics:</h5>
2157
2158<p>The following table shows the semantics of '<tt>vsetfp</tt>' for
2159floating point types. If either operand is a floating point Not a
2160Number (NaN) value, the operation is unordered, and the value in the
2161first column below is produced at that position. Otherwise, the
2162operation is ordered, and the value in the second column is
2163produced.</p>
2164
2165<table border="1" cellspacing="0" cellpadding="4">
2166 <tbody>
2167 <tr><th>Operation</th><th>If unordered<th>Otherwise true iff</th></tr>
2168 <tr><td><tt>eq</tt></td><td>undefined</td><td>var1 == var2</td></tr>
2169 <tr><td><tt>ne</tt></td><td>undefined</td><td>var1 != var2</td></tr>
2170 <tr><td><tt>lt</tt></td><td>undefined</td><td>var1 &lt; var2</td></tr>
2171 <tr><td><tt>gt</tt></td><td>undefined</td><td>var1 &gt; var2</td></tr>
2172 <tr><td><tt>le</tt></td><td>undefined</td><td>var1 &lt;= var2</td></tr>
2173 <tr><td><tt>ge</tt></td><td>undefined</td><td>var1 &gt;= var2</td></tr>
2174 <tr><td><tt>oeq</tt></td><td>false</td><td>var1 == var2</td></tr>
2175 <tr><td><tt>one</tt></td><td>false</td><td>var1 != var2</td></tr>
2176 <tr><td><tt>olt</tt></td><td>false</td><td>var1 &lt; var2</td></tr>
2177 <tr><td><tt>ogt</tt></td><td>false</td><td>var1 &gt; var2</td></tr>
2178 <tr><td><tt>ole</tt></td><td>false</td><td>var1 &lt;= var2</td></tr>
2179 <tr><td><tt>oge</tt></td><td>false</td><td>var1 &gt;= var2</td></tr>
2180 <tr><td><tt>ueq</tt></td><td>true</td><td>var1 == var2</td></tr>
2181 <tr><td><tt>une</tt></td><td>true</td><td>var1 != var2</td></tr>
2182 <tr><td><tt>ult</tt></td><td>true</td><td>var1 &lt; var2</td></tr>
2183 <tr><td><tt>ugt</tt></td><td>true</td><td>var1 &gt; var2</td></tr>
2184 <tr><td><tt>ule</tt></td><td>true</td><td>var1 &lt;= var2</td></tr>
2185 <tr><td><tt>uge</tt></td><td>true</td><td>var1 &gt;= var2</td></tr>
2186 <tr><td><tt>o</tt></td><td>false</td><td>always</td></tr>
2187 <tr><td><tt>u</tt></td><td>true</td><td>never</td></tr>
2188 <tr><td><tt>true</tt></td><td>true</td><td>always</td></tr>
2189 <tr><td><tt>false</tt></td><td>false</td><td>never</td></tr>
2190 </tbody>
2191</table>
2192
2193<h5>Example:</h5>
2194<pre> &lt;result&gt; = vsetfp eq &lt;2 x float&gt; &lt;float 0.0, float 1.0&gt;, &lt;float 1.0, float 0.0&gt; <i>; yields {&lt;2 x bool&gt;}:result = false, false</i>
2195 &lt;result&gt; = vsetfp ne &lt;2 x float&gt; &lt;float 0.0, float 1.0&gt;, &lt;float 1.0, float 0.0&gt; <i>; yields {&lt;2 x bool&gt;}:result = true, true</i>
2196 &lt;result&gt; = vsetfp lt &lt;2 x float&gt; &lt;float 0.0, float 1.0&gt;, &lt;float 1.0, float 0.0&gt; <i>; yields {&lt;2 x bool&gt;}:result = true, false</i>
2197 &lt;result&gt; = vsetfp gt &lt;2 x float&gt; &lt;float 0.0, float 1.0&gt;, &lt;float 1.0, float 0.0&gt; <i>; yields {&lt;2 x bool&gt;}:result = false, true</i>
2198 &lt;result&gt; = vsetfp le &lt;2 x float&gt; &lt;float 0.0, float 1.0&gt;, &lt;float 1.0, float 0.0&gt; <i>; yields {&lt;2 x bool&gt;}:result = true, false</i>
2199 &lt;result&gt; = vsetfp ge &lt;2 x float&gt; &lt;float 0.0, float 1.0&gt;, &lt;float 1.0, float 0.0&gt; <i>; yields {&lt;2 x bool&gt;}:result = false, true</i>
2200</pre>
2201</div>
2202
2203<!-- _______________________________________________________________________ -->
2204<div class="doc_subsubsection">
2205 <a name="i_vselect">'<tt>vselect</tt>' Instruction</a>
2206</div>
2207
2208<div class="doc_text">
2209
2210<h5>Syntax:</h5>
2211
2212<pre>
2213 &lt;result&gt; = vselect &lt;n x bool&gt; &lt;cond&gt;, &lt;n x &lt;ty&gt;&gt; &lt;val1&gt;, &lt;n x &lt;ty&gt;&gt; &lt;val2&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
2214</pre>
2215
2216<h5>Overview:</h5>
2217
2218<p>
2219The '<tt>vselect</tt>' instruction chooses one value at each position
2220of a vector based on a condition.
2221</p>
2222
2223
2224<h5>Arguments:</h5>
2225
2226<p>
2227The '<tt>vselect</tt>' instruction requires a <a
2228href="#t_packed">packed</a> <tt>bool</tt> value indicating the
2229condition at each vector position, and two values of the same packed
2230type. All three operands must have the same length. The type of the
2231result is the same as the type of the two value operands.</p>
2232
2233<h5>Semantics:</h5>
2234
2235<p>
2236At each position where the <tt>bool</tt> vector is true, that position
2237of the result gets its value from the first value argument; otherwise,
2238it gets its value from the second value argument.
2239</p>
2240
2241<h5>Example:</h5>
2242
2243<pre>
2244 %X = vselect bool &lt;2 x bool&gt; &lt;bool true, bool false&gt;, &lt;2 x ubyte&gt; &lt;ubyte 17, ubyte 17&gt;,
2245 &lt;2 x ubyte&gt; &lt;ubyte 42, ubyte 42&gt; <i>; yields &lt;2 x ubyte&gt;:17, 42</i>
2246</pre>
2247</div>
2248
2249
2250
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2251<!-- ======================================================================= -->
2252<div class="doc_subsection">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2253 <a name="memoryops">Memory Access Operations</a>
2254</div>
2255
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2256<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2257
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2258<p>A key design point of an SSA-based representation is how it
2259represents memory. In LLVM, no memory locations are in SSA form, which
2260makes things very simple. This section describes how to read, write,
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2261allocate, and free memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2262
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2263</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2264
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2265<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2266<div class="doc_subsubsection">
2267 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2268</div>
2269
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2270<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2271
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2272<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2273
2274<pre>
2275 &lt;result&gt; = malloc &lt;type&gt;[, uint &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2276</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2277
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2278<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2279
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2280<p>The '<tt>malloc</tt>' instruction allocates memory from the system
2281heap and returns a pointer to it.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2282
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2283<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2284
2285<p>The '<tt>malloc</tt>' instruction allocates
2286<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswell6e4ca612004-02-24 16:13:56 +0000[diff] [blame]2287bytes of memory from the operating system and returns a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2288appropriate type to the program. If "NumElements" is specified, it is the
2289number of elements allocated. If an alignment is specified, the value result
2290of the allocation is guaranteed to be aligned to at least that boundary. If
2291not specified, or if zero, the target can choose to align the allocation on any
2292convenient boundary.</p>
2293
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2294<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2295
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2296<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2297
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2298<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
2299a pointer is returned.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2300
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2301<h5>Example:</h5>
2302
2303<pre>
2304 %array = malloc [4 x ubyte ] <i>; yields {[%4 x ubyte]*}:array</i>
2305
2306 %size = <a href="#i_add">add</a> uint 2, 2 <i>; yields {uint}:size = uint 4</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2307 %array1 = malloc ubyte, uint 4 <i>; yields {ubyte*}:array1</i>
2308 %array2 = malloc [12 x ubyte], uint %size <i>; yields {[12 x ubyte]*}:array2</i>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2309 %array3 = malloc int, uint 4, align 1024 <i>; yields {int*}:array3</i>
2310 %array4 = malloc int, align 1024 <i>; yields {int*}:array4</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2311</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2312</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2313
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2314<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2315<div class="doc_subsubsection">
2316 <a name="i_free">'<tt>free</tt>' Instruction</a>
2317</div>
2318
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2319<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2320
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2321<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2322
2323<pre>
2324 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2325</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2326
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2327<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2328
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2329<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2330memory heap to be reallocated in the future.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2331
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2332<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2333
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2334<p>'<tt>value</tt>' shall be a pointer value that points to a value
2335that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
2336instruction.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2337
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2338<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2339
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2340<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2341after this instruction executes.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2342
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2343<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2344
2345<pre>
2346 %array = <a href="#i_malloc">malloc</a> [4 x ubyte] <i>; yields {[4 x ubyte]*}:array</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2347 free [4 x ubyte]* %array
2348</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2349</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2350
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2351<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2352<div class="doc_subsubsection">
2353 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
2354</div>
2355
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2356<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2357
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2358<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2359
2360<pre>
2361 &lt;result&gt; = alloca &lt;type&gt;[, uint &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2362</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2363
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2364<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2365
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2366<p>The '<tt>alloca</tt>' instruction allocates memory on the current
2367stack frame of the procedure that is live until the current function
2368returns to its caller.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2369
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2370<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2371
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2372<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2373bytes of memory on the runtime stack, returning a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2374appropriate type to the program. If "NumElements" is specified, it is the
2375number of elements allocated. If an alignment is specified, the value result
2376of the allocation is guaranteed to be aligned to at least that boundary. If
2377not specified, or if zero, the target can choose to align the allocation on any
2378convenient boundary.</p>
2379
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2380<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2381
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2382<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2383
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2384<p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2385memory is automatically released when the function returns. The '<tt>alloca</tt>'
2386instruction is commonly used to represent automatic variables that must
2387have an address available. When the function returns (either with the <tt><a
John Criswelldae2e932005-05-12 16:55:34 +0000[diff] [blame]2388 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]2389instructions), the memory is reclaimed.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2390
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2391<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2392
2393<pre>
2394 %ptr = alloca int <i>; yields {int*}:ptr</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2395 %ptr = alloca int, uint 4 <i>; yields {int*}:ptr</i>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2396 %ptr = alloca int, uint 4, align 1024 <i>; yields {int*}:ptr</i>
2397 %ptr = alloca int, align 1024 <i>; yields {int*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2398</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2399</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2400
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2401<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2402<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
2403Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2404<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2405<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2406<pre> &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;<br> &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;<br></pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2407<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2408<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2409<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2410<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2411address from which to load. The pointer must point to a <a
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]2412 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2413marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2414the number or order of execution of this <tt>load</tt> with other
2415volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
2416instructions. </p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2417<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2418<p>The location of memory pointed to is loaded.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2419<h5>Examples:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2420<pre> %ptr = <a href="#i_alloca">alloca</a> int <i>; yields {int*}:ptr</i>
2421 <a
2422 href="#i_store">store</a> int 3, int* %ptr <i>; yields {void}</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2423 %val = load int* %ptr <i>; yields {int}:val = int 3</i>
2424</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2425</div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2426<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2427<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
2428Instruction</a> </div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2429<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2430<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt; <i>; yields {void}</i>
Chris Lattnerf0651072003-09-08 18:27:49 +0000[diff] [blame]2431 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt; <i>; yields {void}</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2432</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2433<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2434<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2435<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2436<p>There are two arguments to the '<tt>store</tt>' instruction: a value
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2437to store and an address in which to store it. The type of the '<tt>&lt;pointer&gt;</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2438operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2439operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2440optimizer is not allowed to modify the number or order of execution of
2441this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
2442 href="#i_store">store</a></tt> instructions.</p>
2443<h5>Semantics:</h5>
2444<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
2445at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2446<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2447<pre> %ptr = <a href="#i_alloca">alloca</a> int <i>; yields {int*}:ptr</i>
2448 <a
2449 href="#i_store">store</a> int 3, int* %ptr <i>; yields {void}</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2450 %val = load int* %ptr <i>; yields {int}:val = int 3</i>
2451</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2452<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2453<div class="doc_subsubsection">
2454 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
2455</div>
2456
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2457<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2458<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2459<pre>
2460 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
2461</pre>
2462
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2463<h5>Overview:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2464
2465<p>
2466The '<tt>getelementptr</tt>' instruction is used to get the address of a
2467subelement of an aggregate data structure.</p>
2468
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2469<h5>Arguments:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2470
2471<p>This instruction takes a list of integer constants that indicate what
2472elements of the aggregate object to index to. The actual types of the arguments
2473provided depend on the type of the first pointer argument. The
2474'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2475levels of a structure or to a specific index in an array. When indexing into a
2476structure, only <tt>uint</tt>
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2477integer constants are allowed. When indexing into an array or pointer,
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2478<tt>int</tt> and <tt>long</tt> indexes are allowed of any sign.</p>
2479
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2480<p>For example, let's consider a C code fragment and how it gets
2481compiled to LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2482
2483<pre>
2484 struct RT {
2485 char A;
2486 int B[10][20];
2487 char C;
2488 };
2489 struct ST {
2490 int X;
2491 double Y;
2492 struct RT Z;
2493 };
2494
2495 int *foo(struct ST *s) {
2496 return &amp;s[1].Z.B[5][13];
2497 }
2498</pre>
2499
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2500<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2501
2502<pre>
2503 %RT = type { sbyte, [10 x [20 x int]], sbyte }
2504 %ST = type { int, double, %RT }
2505
Brian Gaeke7283e7c2004-07-02 21:08:14 +0000[diff] [blame]2506 implementation
2507
2508 int* %foo(%ST* %s) {
2509 entry:
2510 %reg = getelementptr %ST* %s, int 1, uint 2, uint 1, int 5, int 13
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2511 ret int* %reg
2512 }
2513</pre>
2514
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2515<h5>Semantics:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2516
2517<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2518on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]2519and <a href="#t_array">array</a> types require <tt>uint</tt>, <tt>int</tt>,
2520<tt>ulong</tt>, or <tt>long</tt> values, and <a href="#t_struct">structure</a>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2521types require <tt>uint</tt> <b>constants</b>.</p>
2522
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2523<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2524type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ int, double, %RT
2525}</tt>' type, a structure. The second index indexes into the third element of
2526the structure, yielding a '<tt>%RT</tt>' = '<tt>{ sbyte, [10 x [20 x int]],
2527sbyte }</tt>' type, another structure. The third index indexes into the second
2528element of the structure, yielding a '<tt>[10 x [20 x int]]</tt>' type, an
2529array. The two dimensions of the array are subscripted into, yielding an
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2530'<tt>int</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2531to this element, thus computing a value of '<tt>int*</tt>' type.</p>
2532
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2533<p>Note that it is perfectly legal to index partially through a
2534structure, returning a pointer to an inner element. Because of this,
2535the LLVM code for the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2536
2537<pre>
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]2538 int* %foo(%ST* %s) {
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2539 %t1 = getelementptr %ST* %s, int 1 <i>; yields %ST*:%t1</i>
2540 %t2 = getelementptr %ST* %t1, int 0, uint 2 <i>; yields %RT*:%t2</i>
2541 %t3 = getelementptr %RT* %t2, int 0, uint 1 <i>; yields [10 x [20 x int]]*:%t3</i>
2542 %t4 = getelementptr [10 x [20 x int]]* %t3, int 0, int 5 <i>; yields [20 x int]*:%t4</i>
2543 %t5 = getelementptr [20 x int]* %t4, int 0, int 13 <i>; yields int*:%t5</i>
2544 ret int* %t5
2545 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2546</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2547
2548<p>Note that it is undefined to access an array out of bounds: array and
2549pointer indexes must always be within the defined bounds of the array type.
2550The one exception for this rules is zero length arrays. These arrays are
2551defined to be accessible as variable length arrays, which requires access
2552beyond the zero'th element.</p>
2553
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2554<h5>Example:</h5>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2555
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2556<pre>
2557 <i>; yields [12 x ubyte]*:aptr</i>
2558 %aptr = getelementptr {int, [12 x ubyte]}* %sptr, long 0, uint 1
2559</pre>
2560
2561</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2562<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2563<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2564<div class="doc_text">
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]2565<p>The instructions in this category are the "miscellaneous"
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2566instructions, which defy better classification.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2567</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2568<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2569<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
2570Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2571<div class="doc_text">
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2572<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2573<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2574<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2575<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
2576the SSA graph representing the function.</p>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2577<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2578<p>The type of the incoming values are specified with the first type
2579field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
2580as arguments, with one pair for each predecessor basic block of the
2581current block. Only values of <a href="#t_firstclass">first class</a>
2582type may be used as the value arguments to the PHI node. Only labels
2583may be used as the label arguments.</p>
2584<p>There must be no non-phi instructions between the start of a basic
2585block and the PHI instructions: i.e. PHI instructions must be first in
2586a basic block.</p>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2587<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2588<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the
2589value specified by the parameter, depending on which basic block we
2590came from in the last <a href="#terminators">terminator</a> instruction.</p>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2591<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2592<pre>Loop: ; Infinite loop that counts from 0 on up...<br> %indvar = phi uint [ 0, %LoopHeader ], [ %nextindvar, %Loop ]<br> %nextindvar = add uint %indvar, 1<br> br label %Loop<br></pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2593</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2594
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2595<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2596<div class="doc_subsubsection">
2597 <a name="i_cast">'<tt>cast .. to</tt>' Instruction</a>
2598</div>
2599
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2600<div class="doc_text">
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2601
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2602<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2603
2604<pre>
2605 &lt;result&gt; = cast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2606</pre>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2607
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2608<h5>Overview:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2609
2610<p>
2611The '<tt>cast</tt>' instruction is used as the primitive means to convert
2612integers to floating point, change data type sizes, and break type safety (by
2613casting pointers).
2614</p>
2615
2616
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2617<h5>Arguments:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2618
2619<p>
2620The '<tt>cast</tt>' instruction takes a value to cast, which must be a first
2621class value, and a type to cast it to, which must also be a <a
2622href="#t_firstclass">first class</a> type.
2623</p>
2624
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2625<h5>Semantics:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2626
2627<p>
2628This instruction follows the C rules for explicit casts when determining how the
2629data being cast must change to fit in its new container.
2630</p>
2631
2632<p>
2633When casting to bool, any value that would be considered true in the context of
2634a C '<tt>if</tt>' condition is converted to the boolean '<tt>true</tt>' values,
2635all else are '<tt>false</tt>'.
2636</p>
2637
2638<p>
2639When extending an integral value from a type of one signness to another (for
2640example '<tt>sbyte</tt>' to '<tt>ulong</tt>'), the value is sign-extended if the
2641<b>source</b> value is signed, and zero-extended if the source value is
2642unsigned. <tt>bool</tt> values are always zero extended into either zero or
2643one.
2644</p>
2645
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2646<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2647
2648<pre>
2649 %X = cast int 257 to ubyte <i>; yields ubyte:1</i>
Chris Lattner7bae3952002-06-25 18:03:17 +0000[diff] [blame]2650 %Y = cast int 123 to bool <i>; yields bool:true</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2651</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2652</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2653
2654<!-- _______________________________________________________________________ -->
2655<div class="doc_subsubsection">
2656 <a name="i_select">'<tt>select</tt>' Instruction</a>
2657</div>
2658
2659<div class="doc_text">
2660
2661<h5>Syntax:</h5>
2662
2663<pre>
2664 &lt;result&gt; = select bool &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
2665</pre>
2666
2667<h5>Overview:</h5>
2668
2669<p>
2670The '<tt>select</tt>' instruction is used to choose one value based on a
2671condition, without branching.
2672</p>
2673
2674
2675<h5>Arguments:</h5>
2676
2677<p>
2678The '<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.
2679</p>
2680
2681<h5>Semantics:</h5>
2682
2683<p>
2684If the boolean condition evaluates to true, the instruction returns the first
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2685value argument; otherwise, it returns the second value argument.
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2686</p>
2687
2688<h5>Example:</h5>
2689
2690<pre>
2691 %X = select bool true, ubyte 17, ubyte 42 <i>; yields ubyte:17</i>
2692</pre>
2693</div>
2694
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]2695
2696<!-- _______________________________________________________________________ -->
2697<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2698 <a name="i_call">'<tt>call</tt>' Instruction</a>
2699</div>
2700
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2701<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2702
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2703<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2704<pre>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2705 &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]2706</pre>
2707
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2708<h5>Overview:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2709
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2710<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2711
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2712<h5>Arguments:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2713
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2714<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2715
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2716<ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2717 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2718 <p>The optional "tail" marker indicates whether the callee function accesses
2719 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2720 function call is eligible for tail call optimization. Note that calls may
2721 be marked "tail" even if they do not occur before a <a
2722 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2723 </li>
2724 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2725 <p>The optional "cconv" marker indicates which <a href="callingconv">calling
2726 convention</a> the call should use. If none is specified, the call defaults
2727 to using C calling conventions.
2728 </li>
2729 <li>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2730 <p>'<tt>ty</tt>': shall be the signature of the pointer to function value
2731 being invoked. The argument types must match the types implied by this
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2732 signature. This type can be omitted if the function is not varargs and
2733 if the function type does not return a pointer to a function.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2734 </li>
2735 <li>
2736 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
2737 be invoked. In most cases, this is a direct function invocation, but
2738 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2739 to function value.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2740 </li>
2741 <li>
2742 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencera7e302a2005-05-01 22:22:57 +0000[diff] [blame]2743 function signature argument types. All arguments must be of
2744 <a href="#t_firstclass">first class</a> type. If the function signature
2745 indicates the function accepts a variable number of arguments, the extra
2746 arguments can be specified.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2747 </li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2748</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2749
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2750<h5>Semantics:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2751
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2752<p>The '<tt>call</tt>' instruction is used to cause control flow to
2753transfer to a specified function, with its incoming arguments bound to
2754the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
2755instruction in the called function, control flow continues with the
2756instruction after the function call, and the return value of the
2757function is bound to the result argument. This is a simpler case of
2758the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2759
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2760<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2761
2762<pre>
2763 %retval = call int %test(int %argc)
2764 call int(sbyte*, ...) *%printf(sbyte* %msg, int 12, sbyte 42);
2765 %X = tail call int %foo()
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2766 %Y = tail call <a href="#callingconv">fastcc</a> int %foo()
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2767</pre>
2768
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2769</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2770
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2771<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2772<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]2773 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2774</div>
2775
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2776<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2777
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2778<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2779
2780<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2781 &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]2782</pre>
2783
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2784<h5>Overview:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2785
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2786<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2787the "variable argument" area of a function call. It is used to implement the
2788<tt>va_arg</tt> macro in C.</p>
2789
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2790<h5>Arguments:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2791
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2792<p>This instruction takes a <tt>va_list*</tt> value and the type of
2793the argument. It returns a value of the specified argument type and
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]2794increments the <tt>va_list</tt> to point to the next argument. Again, the
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2795actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2796
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2797<h5>Semantics:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2798
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2799<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
2800type from the specified <tt>va_list</tt> and causes the
2801<tt>va_list</tt> to point to the next argument. For more information,
2802see the variable argument handling <a href="#int_varargs">Intrinsic
2803Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2804
2805<p>It is legal for this instruction to be called in a function which does not
2806take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2807function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2808
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2809<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2810href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2811argument.</p>
2812
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2813<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2814
2815<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
2816
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2817</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2818
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2819<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2820<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
2821<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2822
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2823<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2824
2825<p>LLVM supports the notion of an "intrinsic function". These functions have
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2826well known names and semantics and are required to follow certain
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2827restrictions. Overall, these instructions represent an extension mechanism for
2828the LLVM language that does not require changing all of the transformations in
2829LLVM to add to the language (or the bytecode reader/writer, the parser,
2830etc...).</p>
2831
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2832<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
2833prefix is reserved in LLVM for intrinsic names; thus, functions may not be named
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2834this. Intrinsic functions must always be external functions: you cannot define
2835the body of intrinsic functions. Intrinsic functions may only be used in call
2836or invoke instructions: it is illegal to take the address of an intrinsic
2837function. Additionally, because intrinsic functions are part of the LLVM
2838language, it is required that they all be documented here if any are added.</p>
2839
2840
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2841<p>To learn how to add an intrinsic function, please see the <a
Chris Lattner590cff32005-05-11 03:35:57 +0000[diff] [blame]2842href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2843</p>
2844
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2845</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2846
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2847<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2848<div class="doc_subsection">
2849 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
2850</div>
2851
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2852<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2853
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2854<p>Variable argument support is defined in LLVM with the <a
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]2855 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2856intrinsic functions. These functions are related to the similarly
2857named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2858
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2859<p>All of these functions operate on arguments that use a
2860target-specific value type "<tt>va_list</tt>". The LLVM assembly
2861language reference manual does not define what this type is, so all
2862transformations should be prepared to handle intrinsics with any type
2863used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2864
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2865<p>This example shows how the <a href="#i_vanext"><tt>vanext</tt></a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2866instruction and the variable argument handling intrinsic functions are
2867used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2868
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2869<pre>
2870int %test(int %X, ...) {
2871 ; Initialize variable argument processing
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2872 %ap = alloca sbyte*
2873 call void %<a href="#i_va_start">llvm.va_start</a>(sbyte** %ap)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2874
2875 ; Read a single integer argument
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2876 %tmp = va_arg sbyte** %ap, int
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2877
2878 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2879 %aq = alloca sbyte*
Andrew Lenharthd0a4c622005-06-22 20:38:11 +0000[diff] [blame]2880 call void %<a href="#i_va_copy">llvm.va_copy</a>(sbyte** %aq, sbyte** %ap)
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2881 call void %<a href="#i_va_end">llvm.va_end</a>(sbyte** %aq)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2882
2883 ; Stop processing of arguments.
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2884 call void %<a href="#i_va_end">llvm.va_end</a>(sbyte** %ap)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2885 ret int %tmp
2886}
2887</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2888</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2889
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2890<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2891<div class="doc_subsubsection">
2892 <a name="i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
2893</div>
2894
2895
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2896<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2897<h5>Syntax:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2898<pre> declare void %llvm.va_start(&lt;va_list&gt;* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2899<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2900<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
2901<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
2902href="#i_va_arg">va_arg</a></tt>.</p>
2903
2904<h5>Arguments:</h5>
2905
2906<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
2907
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2908<h5>Semantics:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2909
2910<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
2911macro available in C. In a target-dependent way, it initializes the
2912<tt>va_list</tt> element the argument points to, so that the next call to
2913<tt>va_arg</tt> will produce the first variable argument passed to the function.
2914Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
2915last argument of the function, the compiler can figure that out.</p>
2916
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2917</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2918
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2919<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2920<div class="doc_subsubsection">
2921 <a name="i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
2922</div>
2923
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2924<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2925<h5>Syntax:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2926<pre> declare void %llvm.va_end(&lt;va_list*&gt; &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2927<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2928<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>&lt;arglist&gt;</tt>
2929which has been initialized previously with <tt><a href="#i_va_start">llvm.va_start</a></tt>
2930or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2931<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2932<p>The argument is a <tt>va_list</tt> to destroy.</p>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2933<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2934<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2935macro available in C. In a target-dependent way, it destroys the <tt>va_list</tt>.
2936Calls to <a href="#i_va_start"><tt>llvm.va_start</tt></a> and <a
2937 href="#i_va_copy"><tt>llvm.va_copy</tt></a> must be matched exactly
2938with calls to <tt>llvm.va_end</tt>.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2939</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2940
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2941<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2942<div class="doc_subsubsection">
2943 <a name="i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
2944</div>
2945
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2946<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2947
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2948<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2949
2950<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2951 declare void %llvm.va_copy(&lt;va_list&gt;* &lt;destarglist&gt;,
Andrew Lenharthd0a4c622005-06-22 20:38:11 +0000[diff] [blame]2952 &lt;va_list&gt;* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2953</pre>
2954
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2955<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2956
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2957<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position from
2958the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2959
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2960<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2961
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2962<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]2963The 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]2964
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2965
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2966<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2967
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2968<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt> macro
2969available in C. In a target-dependent way, it copies the source
2970<tt>va_list</tt> element into the destination list. This intrinsic is necessary
2971because the <tt><a href="i_va_begin">llvm.va_begin</a></tt> intrinsic may be
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2972arbitrarily complex and require memory allocation, for example.</p>
2973
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2974</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2975
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2976<!-- ======================================================================= -->
2977<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2978 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
2979</div>
2980
2981<div class="doc_text">
2982
2983<p>
2984LLVM support for <a href="GarbageCollection.html">Accurate Garbage
2985Collection</a> requires the implementation and generation of these intrinsics.
2986These intrinsics allow identification of <a href="#i_gcroot">GC roots on the
2987stack</a>, as well as garbage collector implementations that require <a
2988href="#i_gcread">read</a> and <a href="#i_gcwrite">write</a> barriers.
2989Front-ends for type-safe garbage collected languages should generate these
2990intrinsics to make use of the LLVM garbage collectors. For more details, see <a
2991href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
2992</p>
2993</div>
2994
2995<!-- _______________________________________________________________________ -->
2996<div class="doc_subsubsection">
2997 <a name="i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
2998</div>
2999
3000<div class="doc_text">
3001
3002<h5>Syntax:</h5>
3003
3004<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]3005 declare void %llvm.gcroot(&lt;ty&gt;** %ptrloc, &lt;ty2&gt;* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3006</pre>
3007
3008<h5>Overview:</h5>
3009
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]3010<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]3011the code generator, and allows some metadata to be associated with it.</p>
3012
3013<h5>Arguments:</h5>
3014
3015<p>The first argument specifies the address of a stack object that contains the
3016root pointer. The second pointer (which must be either a constant or a global
3017value address) contains the meta-data to be associated with the root.</p>
3018
3019<h5>Semantics:</h5>
3020
3021<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
3022location. At compile-time, the code generator generates information to allow
3023the runtime to find the pointer at GC safe points.
3024</p>
3025
3026</div>
3027
3028
3029<!-- _______________________________________________________________________ -->
3030<div class="doc_subsubsection">
3031 <a name="i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
3032</div>
3033
3034<div class="doc_text">
3035
3036<h5>Syntax:</h5>
3037
3038<pre>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3039 declare sbyte* %llvm.gcread(sbyte* %ObjPtr, sbyte** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3040</pre>
3041
3042<h5>Overview:</h5>
3043
3044<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
3045locations, allowing garbage collector implementations that require read
3046barriers.</p>
3047
3048<h5>Arguments:</h5>
3049
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3050<p>The second argument is the address to read from, which should be an address
3051allocated from the garbage collector. The first object is a pointer to the
3052start of the referenced object, if needed by the language runtime (otherwise
3053null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3054
3055<h5>Semantics:</h5>
3056
3057<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
3058instruction, but may be replaced with substantially more complex code by the
3059garbage collector runtime, as needed.</p>
3060
3061</div>
3062
3063
3064<!-- _______________________________________________________________________ -->
3065<div class="doc_subsubsection">
3066 <a name="i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
3067</div>
3068
3069<div class="doc_text">
3070
3071<h5>Syntax:</h5>
3072
3073<pre>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3074 declare void %llvm.gcwrite(sbyte* %P1, sbyte* %Obj, sbyte** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3075</pre>
3076
3077<h5>Overview:</h5>
3078
3079<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
3080locations, allowing garbage collector implementations that require write
3081barriers (such as generational or reference counting collectors).</p>
3082
3083<h5>Arguments:</h5>
3084
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3085<p>The first argument is the reference to store, the second is the start of the
3086object to store it to, and the third is the address of the field of Obj to
3087store to. If the runtime does not require a pointer to the object, Obj may be
3088null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3089
3090<h5>Semantics:</h5>
3091
3092<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
3093instruction, but may be replaced with substantially more complex code by the
3094garbage collector runtime, as needed.</p>
3095
3096</div>
3097
3098
3099
3100<!-- ======================================================================= -->
3101<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3102 <a name="int_codegen">Code Generator Intrinsics</a>
3103</div>
3104
3105<div class="doc_text">
3106<p>
3107These intrinsics are provided by LLVM to expose special features that may only
3108be implemented with code generator support.
3109</p>
3110
3111</div>
3112
3113<!-- _______________________________________________________________________ -->
3114<div class="doc_subsubsection">
3115 <a name="i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
3116</div>
3117
3118<div class="doc_text">
3119
3120<h5>Syntax:</h5>
3121<pre>
Chris Lattnerfcf39d42006-01-13 01:20:27 +0000[diff] [blame]3122 declare sbyte *%llvm.returnaddress(uint &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3123</pre>
3124
3125<h5>Overview:</h5>
3126
3127<p>
3128The '<tt>llvm.returnaddress</tt>' intrinsic returns a target-specific value
3129indicating the return address of the current function or one of its callers.
3130</p>
3131
3132<h5>Arguments:</h5>
3133
3134<p>
3135The argument to this intrinsic indicates which function to return the address
3136for. Zero indicates the calling function, one indicates its caller, etc. The
3137argument is <b>required</b> to be a constant integer value.
3138</p>
3139
3140<h5>Semantics:</h5>
3141
3142<p>
3143The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
3144the return address of the specified call frame, or zero if it cannot be
3145identified. The value returned by this intrinsic is likely to be incorrect or 0
3146for arguments other than zero, so it should only be used for debugging purposes.
3147</p>
3148
3149<p>
3150Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]3151aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3152source-language caller.
3153</p>
3154</div>
3155
3156
3157<!-- _______________________________________________________________________ -->
3158<div class="doc_subsubsection">
3159 <a name="i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
3160</div>
3161
3162<div class="doc_text">
3163
3164<h5>Syntax:</h5>
3165<pre>
Chris Lattnerfcf39d42006-01-13 01:20:27 +0000[diff] [blame]3166 declare sbyte *%llvm.frameaddress(uint &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3167</pre>
3168
3169<h5>Overview:</h5>
3170
3171<p>
3172The '<tt>llvm.frameaddress</tt>' intrinsic returns the target-specific frame
3173pointer value for the specified stack frame.
3174</p>
3175
3176<h5>Arguments:</h5>
3177
3178<p>
3179The argument to this intrinsic indicates which function to return the frame
3180pointer for. Zero indicates the calling function, one indicates its caller,
3181etc. The argument is <b>required</b> to be a constant integer value.
3182</p>
3183
3184<h5>Semantics:</h5>
3185
3186<p>
3187The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
3188the frame address of the specified call frame, or zero if it cannot be
3189identified. The value returned by this intrinsic is likely to be incorrect or 0
3190for arguments other than zero, so it should only be used for debugging purposes.
3191</p>
3192
3193<p>
3194Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]3195aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3196source-language caller.
3197</p>
3198</div>
3199
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3200<!-- _______________________________________________________________________ -->
3201<div class="doc_subsubsection">
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]3202 <a name="i_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
3203</div>
3204
3205<div class="doc_text">
3206
3207<h5>Syntax:</h5>
3208<pre>
3209 declare sbyte *%llvm.stacksave()
3210</pre>
3211
3212<h5>Overview:</h5>
3213
3214<p>
3215The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
3216the function stack, for use with <a href="#i_stackrestore">
3217<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
3218features like scoped automatic variable sized arrays in C99.
3219</p>
3220
3221<h5>Semantics:</h5>
3222
3223<p>
3224This intrinsic returns a opaque pointer value that can be passed to <a
3225href="#i_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
3226<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
3227<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
3228state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
3229practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
3230that were allocated after the <tt>llvm.stacksave</tt> was executed.
3231</p>
3232
3233</div>
3234
3235<!-- _______________________________________________________________________ -->
3236<div class="doc_subsubsection">
3237 <a name="i_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
3238</div>
3239
3240<div class="doc_text">
3241
3242<h5>Syntax:</h5>
3243<pre>
3244 declare void %llvm.stackrestore(sbyte* %ptr)
3245</pre>
3246
3247<h5>Overview:</h5>
3248
3249<p>
3250The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
3251the function stack to the state it was in when the corresponding <a
3252href="#llvm.stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
3253useful for implementing language features like scoped automatic variable sized
3254arrays in C99.
3255</p>
3256
3257<h5>Semantics:</h5>
3258
3259<p>
3260See the description for <a href="#i_stacksave"><tt>llvm.stacksave</tt></a>.
3261</p>
3262
3263</div>
3264
3265
3266<!-- _______________________________________________________________________ -->
3267<div class="doc_subsubsection">
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3268 <a name="i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
3269</div>
3270
3271<div class="doc_text">
3272
3273<h5>Syntax:</h5>
3274<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]3275 declare void %llvm.prefetch(sbyte * &lt;address&gt;,
3276 uint &lt;rw&gt;, uint &lt;locality&gt;)
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3277</pre>
3278
3279<h5>Overview:</h5>
3280
3281
3282<p>
3283The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3284a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
3285no
3286effect on the behavior of the program but can change its performance
Chris Lattner2a615362005-02-28 19:47:14 +0000[diff] [blame]3287characteristics.
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3288</p>
3289
3290<h5>Arguments:</h5>
3291
3292<p>
3293<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
3294determining if the fetch should be for a read (0) or write (1), and
3295<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattneraeffb4a2005-03-07 20:31:38 +0000[diff] [blame]3296locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3297<tt>locality</tt> arguments must be constant integers.
3298</p>
3299
3300<h5>Semantics:</h5>
3301
3302<p>
3303This intrinsic does not modify the behavior of the program. In particular,
3304prefetches cannot trap and do not produce a value. On targets that support this
3305intrinsic, the prefetch can provide hints to the processor cache for better
3306performance.
3307</p>
3308
3309</div>
3310
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]3311<!-- _______________________________________________________________________ -->
3312<div class="doc_subsubsection">
3313 <a name="i_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
3314</div>
3315
3316<div class="doc_text">
3317
3318<h5>Syntax:</h5>
3319<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]3320 declare void %llvm.pcmarker( uint &lt;id&gt; )
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]3321</pre>
3322
3323<h5>Overview:</h5>
3324
3325
3326<p>
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3327The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
3328(PC) in a region of
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]3329code to simulators and other tools. The method is target specific, but it is
3330expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]3331The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnerd07c3f42005-11-15 06:07:55 +0000[diff] [blame]3332after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb3e7afd2006-03-24 07:16:10 +0000[diff] [blame]3333optimizations. The intended use is to be inserted after optimizations to allow
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3334correlations of simulation runs.
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]3335</p>
3336
3337<h5>Arguments:</h5>
3338
3339<p>
3340<tt>id</tt> is a numerical id identifying the marker.
3341</p>
3342
3343<h5>Semantics:</h5>
3344
3345<p>
3346This intrinsic does not modify the behavior of the program. Backends that do not
3347support this intrinisic may ignore it.
3348</p>
3349
3350</div>
3351
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]3352<!-- _______________________________________________________________________ -->
3353<div class="doc_subsubsection">
3354 <a name="i_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
3355</div>
3356
3357<div class="doc_text">
3358
3359<h5>Syntax:</h5>
3360<pre>
3361 declare ulong %llvm.readcyclecounter( )
3362</pre>
3363
3364<h5>Overview:</h5>
3365
3366
3367<p>
3368The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
3369counter register (or similar low latency, high accuracy clocks) on those targets
3370that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
3371As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
3372should only be used for small timings.
3373</p>
3374
3375<h5>Semantics:</h5>
3376
3377<p>
3378When directly supported, reading the cycle counter should not modify any memory.
3379Implementations are allowed to either return a application specific value or a
3380system wide value. On backends without support, this is lowered to a constant 0.
3381</p>
3382
3383</div>
3384
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3385<!-- ======================================================================= -->
3386<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3387 <a name="int_libc">Standard C Library Intrinsics</a>
3388</div>
3389
3390<div class="doc_text">
3391<p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3392LLVM provides intrinsics for a few important standard C library functions.
3393These intrinsics allow source-language front-ends to pass information about the
3394alignment of the pointer arguments to the code generator, providing opportunity
3395for more efficient code generation.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3396</p>
3397
3398</div>
3399
3400<!-- _______________________________________________________________________ -->
3401<div class="doc_subsubsection">
3402 <a name="i_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
3403</div>
3404
3405<div class="doc_text">
3406
3407<h5>Syntax:</h5>
3408<pre>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3409 declare void %llvm.memcpy.i32(sbyte* &lt;dest&gt;, sbyte* &lt;src&gt;,
3410 uint &lt;len&gt;, uint &lt;align&gt;)
3411 declare void %llvm.memcpy.i64(sbyte* &lt;dest&gt;, sbyte* &lt;src&gt;,
3412 ulong &lt;len&gt;, uint &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3413</pre>
3414
3415<h5>Overview:</h5>
3416
3417<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3418The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3419location to the destination location.
3420</p>
3421
3422<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3423Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
3424intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3425</p>
3426
3427<h5>Arguments:</h5>
3428
3429<p>
3430The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3431the source. The third argument is an integer argument
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3432specifying the number of bytes to copy, and the fourth argument is the alignment
3433of the source and destination locations.
3434</p>
3435
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]3436<p>
3437If 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]3438the caller guarantees that both the source and destination pointers are aligned
3439to that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]3440</p>
3441
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3442<h5>Semantics:</h5>
3443
3444<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3445The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3446location to the destination location, which are not allowed to overlap. It
3447copies "len" bytes of memory over. If the argument is known to be aligned to
3448some boundary, this can be specified as the fourth argument, otherwise it should
3449be set to 0 or 1.
3450</p>
3451</div>
3452
3453
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]3454<!-- _______________________________________________________________________ -->
3455<div class="doc_subsubsection">
3456 <a name="i_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
3457</div>
3458
3459<div class="doc_text">
3460
3461<h5>Syntax:</h5>
3462<pre>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3463 declare void %llvm.memmove.i32(sbyte* &lt;dest&gt;, sbyte* &lt;src&gt;,
3464 uint &lt;len&gt;, uint &lt;align&gt;)
3465 declare void %llvm.memmove.i64(sbyte* &lt;dest&gt;, sbyte* &lt;src&gt;,
3466 ulong &lt;len&gt;, uint &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]3467</pre>
3468
3469<h5>Overview:</h5>
3470
3471<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3472The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
3473location to the destination location. It is similar to the
3474'<tt>llvm.memcmp</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]3475</p>
3476
3477<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3478Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
3479intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]3480</p>
3481
3482<h5>Arguments:</h5>
3483
3484<p>
3485The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3486the source. The third argument is an integer argument
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]3487specifying the number of bytes to copy, and the fourth argument is the alignment
3488of the source and destination locations.
3489</p>
3490
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]3491<p>
3492If 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]3493the caller guarantees that the source and destination pointers are aligned to
3494that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]3495</p>
3496
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]3497<h5>Semantics:</h5>
3498
3499<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3500The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]3501location to the destination location, which may overlap. It
3502copies "len" bytes of memory over. If the argument is known to be aligned to
3503some boundary, this can be specified as the fourth argument, otherwise it should
3504be set to 0 or 1.
3505</p>
3506</div>
3507
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3508
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3509<!-- _______________________________________________________________________ -->
3510<div class="doc_subsubsection">
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3511 <a name="i_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3512</div>
3513
3514<div class="doc_text">
3515
3516<h5>Syntax:</h5>
3517<pre>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3518 declare void %llvm.memset.i32(sbyte* &lt;dest&gt;, ubyte &lt;val&gt;,
3519 uint &lt;len&gt;, uint &lt;align&gt;)
3520 declare void %llvm.memset.i64(sbyte* &lt;dest&gt;, ubyte &lt;val&gt;,
3521 ulong &lt;len&gt;, uint &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3522</pre>
3523
3524<h5>Overview:</h5>
3525
3526<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3527The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3528byte value.
3529</p>
3530
3531<p>
3532Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
3533does not return a value, and takes an extra alignment argument.
3534</p>
3535
3536<h5>Arguments:</h5>
3537
3538<p>
3539The first argument is a pointer to the destination to fill, the second is the
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3540byte value to fill it with, the third argument is an integer
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3541argument specifying the number of bytes to fill, and the fourth argument is the
3542known alignment of destination location.
3543</p>
3544
3545<p>
3546If 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]3547the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3548</p>
3549
3550<h5>Semantics:</h5>
3551
3552<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3553The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
3554the
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3555destination location. If the argument is known to be aligned to some boundary,
3556this can be specified as the fourth argument, otherwise it should be set to 0 or
35571.
3558</p>
3559</div>
3560
3561
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]3562<!-- _______________________________________________________________________ -->
3563<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]3564 <a name="i_isunordered">'<tt>llvm.isunordered.*</tt>' Intrinsic</a>
Alkis Evlogimenos26bbe932004-06-13 01:16:15 +0000[diff] [blame]3565</div>
3566
3567<div class="doc_text">
3568
3569<h5>Syntax:</h5>
3570<pre>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]3571 declare bool %llvm.isunordered.f32(float Val1, float Val2)
3572 declare bool %llvm.isunordered.f64(double Val1, double Val2)
Alkis Evlogimenos26bbe932004-06-13 01:16:15 +0000[diff] [blame]3573</pre>
3574
3575<h5>Overview:</h5>
3576
3577<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]3578The '<tt>llvm.isunordered</tt>' intrinsics return true if either or both of the
Alkis Evlogimenos26bbe932004-06-13 01:16:15 +0000[diff] [blame]3579specified floating point values is a NAN.
3580</p>
3581
3582<h5>Arguments:</h5>
3583
3584<p>
3585The arguments are floating point numbers of the same type.
3586</p>
3587
3588<h5>Semantics:</h5>
3589
3590<p>
3591If either or both of the arguments is a SNAN or QNAN, it returns true, otherwise
3592false.
3593</p>
3594</div>
3595
3596
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]3597<!-- _______________________________________________________________________ -->
3598<div class="doc_subsubsection">
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3599 <a name="i_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]3600</div>
3601
3602<div class="doc_text">
3603
3604<h5>Syntax:</h5>
3605<pre>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]3606 declare double %llvm.sqrt.f32(float Val)
3607 declare double %llvm.sqrt.f64(double Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]3608</pre>
3609
3610<h5>Overview:</h5>
3611
3612<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]3613The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]3614returning the same value as the libm '<tt>sqrt</tt>' function would. Unlike
3615<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
3616negative numbers (which allows for better optimization).
3617</p>
3618
3619<h5>Arguments:</h5>
3620
3621<p>
3622The argument and return value are floating point numbers of the same type.
3623</p>
3624
3625<h5>Semantics:</h5>
3626
3627<p>
3628This function returns the sqrt of the specified operand if it is a positive
3629floating point number.
3630</p>
3631</div>
3632
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3633<!-- ======================================================================= -->
3634<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]3635 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3636</div>
3637
3638<div class="doc_text">
3639<p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]3640LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3641These allow efficient code generation for some algorithms.
3642</p>
3643
3644</div>
3645
3646<!-- _______________________________________________________________________ -->
3647<div class="doc_subsubsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]3648 <a name="i_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
3649</div>
3650
3651<div class="doc_text">
3652
3653<h5>Syntax:</h5>
3654<pre>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3655 declare ushort %llvm.bswap.i16(ushort &lt;id&gt;)
3656 declare uint %llvm.bswap.i32(uint &lt;id&gt;)
3657 declare ulong %llvm.bswap.i64(ulong &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]3658</pre>
3659
3660<h5>Overview:</h5>
3661
3662<p>
3663The '<tt>llvm.bwsap</tt>' family of intrinsics is used to byteswap a 16, 32 or
366464 bit quantity. These are useful for performing operations on data that is not
3665in the target's native byte order.
3666</p>
3667
3668<h5>Semantics:</h5>
3669
3670<p>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3671The <tt>llvm.bswap.16</tt> intrinsic returns a ushort value that has the high and low
3672byte of the input ushort swapped. Similarly, the <tt>llvm.bswap.i32</tt> intrinsic
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]3673returns a uint value that has the four bytes of the input uint swapped, so that
3674if the input bytes are numbered 0, 1, 2, 3 then the returned uint will have its
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3675bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i64</tt> intrinsic extends this concept
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]3676to 64 bits.
3677</p>
3678
3679</div>
3680
3681<!-- _______________________________________________________________________ -->
3682<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]3683 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3684</div>
3685
3686<div class="doc_text">
3687
3688<h5>Syntax:</h5>
3689<pre>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3690 declare ubyte %llvm.ctpop.i8 (ubyte &lt;src&gt;)
3691 declare ushort %llvm.ctpop.i16(ushort &lt;src&gt;)
3692 declare uint %llvm.ctpop.i32(uint &lt;src&gt;)
3693 declare ulong %llvm.ctpop.i64(ulong &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3694</pre>
3695
3696<h5>Overview:</h5>
3697
3698<p>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3699The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
3700value.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3701</p>
3702
3703<h5>Arguments:</h5>
3704
3705<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]3706The only argument is the value to be counted. The argument may be of any
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3707unsigned integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3708</p>
3709
3710<h5>Semantics:</h5>
3711
3712<p>
3713The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
3714</p>
3715</div>
3716
3717<!-- _______________________________________________________________________ -->
3718<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]3719 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3720</div>
3721
3722<div class="doc_text">
3723
3724<h5>Syntax:</h5>
3725<pre>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3726 declare ubyte %llvm.ctlz.i8 (ubyte &lt;src&gt;)
3727 declare ushort %llvm.ctlz.i16(ushort &lt;src&gt;)
3728 declare uint %llvm.ctlz.i32(uint &lt;src&gt;)
3729 declare ulong %llvm.ctlz.i64(ulong &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3730</pre>
3731
3732<h5>Overview:</h5>
3733
3734<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]3735The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
3736leading zeros in a variable.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3737</p>
3738
3739<h5>Arguments:</h5>
3740
3741<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]3742The only argument is the value to be counted. The argument may be of any
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3743unsigned integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3744</p>
3745
3746<h5>Semantics:</h5>
3747
3748<p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]3749The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
3750in a variable. If the src == 0 then the result is the size in bits of the type
Chris Lattner99d3c272006-04-21 21:37:40 +0000[diff] [blame^]3751of src. For example, <tt>llvm.ctlz(int 2) = 30</tt>.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3752</p>
3753</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]3754
3755
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]3756
3757<!-- _______________________________________________________________________ -->
3758<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]3759 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]3760</div>
3761
3762<div class="doc_text">
3763
3764<h5>Syntax:</h5>
3765<pre>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3766 declare ubyte %llvm.cttz.i8 (ubyte &lt;src&gt;)
3767 declare ushort %llvm.cttz.i16(ushort &lt;src&gt;)
3768 declare uint %llvm.cttz.i32(uint &lt;src&gt;)
3769 declare ulong %llvm.cttz.i64(ulong &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]3770</pre>
3771
3772<h5>Overview:</h5>
3773
3774<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]3775The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
3776trailing zeros.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]3777</p>
3778
3779<h5>Arguments:</h5>
3780
3781<p>
3782The only argument is the value to be counted. The argument may be of any
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3783unsigned integer type. The return type must match the argument type.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]3784</p>
3785
3786<h5>Semantics:</h5>
3787
3788<p>
3789The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
3790in a variable. If the src == 0 then the result is the size in bits of the type
3791of src. For example, <tt>llvm.cttz(2) = 1</tt>.
3792</p>
3793</div>
3794
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3795<!-- ======================================================================= -->
3796<div class="doc_subsection">
3797 <a name="int_debugger">Debugger Intrinsics</a>
3798</div>
3799
3800<div class="doc_text">
3801<p>
3802The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
3803are described in the <a
3804href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
3805Debugging</a> document.
3806</p>
3807</div>
3808
3809
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3810<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3811<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]3812<address>
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3817
3818 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]3819 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]3820 Last modified: $Date$
3821</address>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3822</body>
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