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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
Chris Lattner5710ce92006-05-19 21:15:36 +0000[diff] [blame]467 <dt><b>"<tt>csretcc</tt>" - The C struct return calling convention</b>:</dt>
468
469 <dd>This calling convention matches the target C calling conventions, except
470 that functions with this convention are required to take a pointer as their
471 first argument, and the return type of the function must be void. This is
472 used for C functions that return aggregates by-value. In this case, the
473 function has been transformed to take a pointer to the struct as the first
474 argument to the function. For targets where the ABI specifies specific
475 behavior for structure-return calls, the calling convention can be used to
476 distinguish between struct return functions and other functions that take a
477 pointer to a struct as the first argument.
478 </dd>
479
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]480 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
481
482 <dd>This calling convention attempts to make calls as fast as possible
483 (e.g. by passing things in registers). This calling convention allows the
484 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner8cdc5bc2005-05-06 23:08:23 +0000[diff] [blame]485 without having to conform to an externally specified ABI. Implementations of
486 this convention should allow arbitrary tail call optimization to be supported.
487 This calling convention does not support varargs and requires the prototype of
488 all callees to exactly match the prototype of the function definition.
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]489 </dd>
490
491 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
492
493 <dd>This calling convention attempts to make code in the caller as efficient
494 as possible under the assumption that the call is not commonly executed. As
495 such, these calls often preserve all registers so that the call does not break
496 any live ranges in the caller side. This calling convention does not support
497 varargs and requires the prototype of all callees to exactly match the
498 prototype of the function definition.
499 </dd>
500
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]501 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]502
503 <dd>Any calling convention may be specified by number, allowing
504 target-specific calling conventions to be used. Target specific calling
505 conventions start at 64.
506 </dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]507</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]508
509<p>More calling conventions can be added/defined on an as-needed basis, to
510support pascal conventions or any other well-known target-independent
511convention.</p>
512
513</div>
514
515<!-- ======================================================================= -->
516<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]517 <a name="globalvars">Global Variables</a>
518</div>
519
520<div class="doc_text">
521
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]522<p>Global variables define regions of memory allocated at compilation time
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]523instead of run-time. Global variables may optionally be initialized, may have
524an explicit section to be placed in, and may
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]525have an optional explicit alignment specified. A
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]526variable may be defined as a global "constant," which indicates that the
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]527contents of the variable will <b>never</b> be modified (enabling better
528optimization, allowing the global data to be placed in the read-only section of
529an executable, etc). Note that variables that need runtime initialization
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]530cannot be marked "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]531
532<p>
533LLVM explicitly allows <em>declarations</em> of global variables to be marked
534constant, even if the final definition of the global is not. This capability
535can be used to enable slightly better optimization of the program, but requires
536the language definition to guarantee that optimizations based on the
537'constantness' are valid for the translation units that do not include the
538definition.
539</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]540
541<p>As SSA values, global variables define pointer values that are in
542scope (i.e. they dominate) all basic blocks in the program. Global
543variables always define a pointer to their "content" type because they
544describe a region of memory, and all memory objects in LLVM are
545accessed through pointers.</p>
546
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]547<p>LLVM allows an explicit section to be specified for globals. If the target
548supports it, it will emit globals to the section specified.</p>
549
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]550<p>An explicit alignment may be specified for a global. If not present, or if
551the alignment is set to zero, the alignment of the global is set by the target
552to whatever it feels convenient. If an explicit alignment is specified, the
553global is forced to have at least that much alignment. All alignments must be
554a power of 2.</p>
555
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]556</div>
557
558
559<!-- ======================================================================= -->
560<div class="doc_subsection">
561 <a name="functionstructure">Functions</a>
562</div>
563
564<div class="doc_text">
565
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]566<p>LLVM function definitions consist of an optional <a href="#linkage">linkage
567type</a>, an optional <a href="#callingconv">calling convention</a>, a return
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]568type, a function name, a (possibly empty) argument list, an optional section,
569an optional alignment, an opening curly brace,
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]570a list of basic blocks, and a closing curly brace. LLVM function declarations
571are defined with the "<tt>declare</tt>" keyword, an optional <a
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]572href="#callingconv">calling convention</a>, a return type, a function name,
573a possibly empty list of arguments, and an optional alignment.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]574
575<p>A function definition contains a list of basic blocks, forming the CFG for
576the function. Each basic block may optionally start with a label (giving the
577basic block a symbol table entry), contains a list of instructions, and ends
578with a <a href="#terminators">terminator</a> instruction (such as a branch or
579function return).</p>
580
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]581<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]582executed on entrance to the function, and it is not allowed to have predecessor
583basic blocks (i.e. there can not be any branches to the entry block of a
584function). Because the block can have no predecessors, it also cannot have any
585<a href="#i_phi">PHI nodes</a>.</p>
586
587<p>LLVM functions are identified by their name and type signature. Hence, two
588functions with the same name but different parameter lists or return values are
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]589considered different functions, and LLVM will resolve references to each
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]590appropriately.</p>
591
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]592<p>LLVM allows an explicit section to be specified for functions. If the target
593supports it, it will emit functions to the section specified.</p>
594
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]595<p>An explicit alignment may be specified for a function. If not present, or if
596the alignment is set to zero, the alignment of the function is set by the target
597to whatever it feels convenient. If an explicit alignment is specified, the
598function is forced to have at least that much alignment. All alignments must be
599a power of 2.</p>
600
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]601</div>
602
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]603<!-- ======================================================================= -->
604<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]605 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]606</div>
607
608<div class="doc_text">
609<p>
610Modules may contain "module-level inline asm" blocks, which corresponds to the
611GCC "file scope inline asm" blocks. These blocks are internally concatenated by
612LLVM and treated as a single unit, but may be separated in the .ll file if
613desired. The syntax is very simple:
614</p>
615
616<div class="doc_code"><pre>
Chris Lattner52599e12006-01-24 00:37:20 +0000[diff] [blame]617 module asm "inline asm code goes here"
618 module asm "more can go here"
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]619</pre></div>
620
621<p>The strings can contain any character by escaping non-printable characters.
622 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
623 for the number.
624</p>
625
626<p>
627 The inline asm code is simply printed to the machine code .s file when
628 assembly code is generated.
629</p>
630</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]631
632
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]633<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]634<div class="doc_section"> <a name="typesystem">Type System</a> </div>
635<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]636
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]637<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]638
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]639<p>The LLVM type system is one of the most important features of the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]640intermediate representation. Being typed enables a number of
641optimizations to be performed on the IR directly, without having to do
642extra analyses on the side before the transformation. A strong type
643system makes it easier to read the generated code and enables novel
644analyses and transformations that are not feasible to perform on normal
645three address code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]646
647</div>
648
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]649<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]650<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]651<div class="doc_text">
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]652<p>The primitive types are the fundamental building blocks of the LLVM
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]653system. The current set of primitive types is as follows:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]654
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]655<table class="layout">
656 <tr class="layout">
657 <td class="left">
658 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]659 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]660 <tr><th>Type</th><th>Description</th></tr>
661 <tr><td><tt>void</tt></td><td>No value</td></tr>
Misha Brukmancfa87bc2005-04-22 18:02:52 +0000[diff] [blame]662 <tr><td><tt>ubyte</tt></td><td>Unsigned 8-bit value</td></tr>
663 <tr><td><tt>ushort</tt></td><td>Unsigned 16-bit value</td></tr>
664 <tr><td><tt>uint</tt></td><td>Unsigned 32-bit value</td></tr>
665 <tr><td><tt>ulong</tt></td><td>Unsigned 64-bit value</td></tr>
666 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]667 <tr><td><tt>label</tt></td><td>Branch destination</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 <td class="right">
672 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]673 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]674 <tr><th>Type</th><th>Description</th></tr>
675 <tr><td><tt>bool</tt></td><td>True or False value</td></tr>
Misha Brukmancfa87bc2005-04-22 18:02:52 +0000[diff] [blame]676 <tr><td><tt>sbyte</tt></td><td>Signed 8-bit value</td></tr>
677 <tr><td><tt>short</tt></td><td>Signed 16-bit value</td></tr>
678 <tr><td><tt>int</tt></td><td>Signed 32-bit value</td></tr>
679 <tr><td><tt>long</tt></td><td>Signed 64-bit value</td></tr>
680 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]681 </tbody>
682 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]683 </td>
684 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]685</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]686</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]687
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]688<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]689<div class="doc_subsubsection"> <a name="t_classifications">Type
690Classifications</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]691<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]692<p>These different primitive types fall into a few useful
693classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]694
695<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]696 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]697 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]698 <tr>
699 <td><a name="t_signed">signed</a></td>
700 <td><tt>sbyte, short, int, long, float, double</tt></td>
701 </tr>
702 <tr>
703 <td><a name="t_unsigned">unsigned</a></td>
704 <td><tt>ubyte, ushort, uint, ulong</tt></td>
705 </tr>
706 <tr>
707 <td><a name="t_integer">integer</a></td>
708 <td><tt>ubyte, sbyte, ushort, short, uint, int, ulong, long</tt></td>
709 </tr>
710 <tr>
711 <td><a name="t_integral">integral</a></td>
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]712 <td><tt>bool, ubyte, sbyte, ushort, short, uint, int, ulong, long</tt>
713 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]714 </tr>
715 <tr>
716 <td><a name="t_floating">floating point</a></td>
717 <td><tt>float, double</tt></td>
718 </tr>
719 <tr>
720 <td><a name="t_firstclass">first class</a></td>
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]721 <td><tt>bool, ubyte, sbyte, ushort, short, uint, int, ulong, long,<br>
722 float, double, <a href="#t_pointer">pointer</a>,
723 <a href="#t_packed">packed</a></tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]724 </tr>
725 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]726</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]727
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]728<p>The <a href="#t_firstclass">first class</a> types are perhaps the
729most important. Values of these types are the only ones which can be
730produced by instructions, passed as arguments, or used as operands to
731instructions. This means that all structures and arrays must be
732manipulated either by pointer or by component.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]733</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]734
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]735<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]736<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]737
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]738<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]739
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]740<p>The real power in LLVM comes from the derived types in the system.
741This is what allows a programmer to represent arrays, functions,
742pointers, and other useful types. Note that these derived types may be
743recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]744
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]745</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]746
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]747<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]748<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]749
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]750<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]751
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]752<h5>Overview:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]753
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]754<p>The array type is a very simple derived type that arranges elements
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]755sequentially in memory. The array type requires a size (number of
756elements) and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]757
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]758<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]759
760<pre>
761 [&lt;# elements&gt; x &lt;elementtype&gt;]
762</pre>
763
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]764<p>The number of elements is a constant integer value; elementtype may
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]765be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]766
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]767<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]768<table class="layout">
769 <tr class="layout">
770 <td class="left">
771 <tt>[40 x int ]</tt><br/>
772 <tt>[41 x int ]</tt><br/>
773 <tt>[40 x uint]</tt><br/>
774 </td>
775 <td class="left">
776 Array of 40 integer values.<br/>
777 Array of 41 integer values.<br/>
778 Array of 40 unsigned integer values.<br/>
779 </td>
780 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]781</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]782<p>Here are some examples of multidimensional arrays:</p>
783<table class="layout">
784 <tr class="layout">
785 <td class="left">
786 <tt>[3 x [4 x int]]</tt><br/>
787 <tt>[12 x [10 x float]]</tt><br/>
788 <tt>[2 x [3 x [4 x uint]]]</tt><br/>
789 </td>
790 <td class="left">
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]791 3x4 array of integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]792 12x10 array of single precision floating point values.<br/>
793 2x3x4 array of unsigned integer values.<br/>
794 </td>
795 </tr>
796</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]797
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]798<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
799length array. Normally, accesses past the end of an array are undefined in
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]800LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
801As a special case, however, zero length arrays are recognized to be variable
802length. This allows implementation of 'pascal style arrays' with the LLVM
803type "{ int, [0 x float]}", for example.</p>
804
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]805</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]806
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]807<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]808<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]809<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]810<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]811<p>The function type can be thought of as a function signature. It
812consists of a return type and a list of formal parameter types.
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]813Function types are usually used to build virtual function tables
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]814(which are structures of pointers to functions), for indirect function
815calls, and when defining a function.</p>
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]816<p>
817The return type of a function type cannot be an aggregate type.
818</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]819<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]820<pre> &lt;returntype&gt; (&lt;parameter list&gt;)<br></pre>
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]821<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]822specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]823which indicates that the function takes a variable number of arguments.
824Variable argument functions can access their arguments with the <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]825 href="#int_varargs">variable argument handling intrinsic</a> functions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]826<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]827<table class="layout">
828 <tr class="layout">
829 <td class="left">
830 <tt>int (int)</tt> <br/>
831 <tt>float (int, int *) *</tt><br/>
832 <tt>int (sbyte *, ...)</tt><br/>
833 </td>
834 <td class="left">
835 function taking an <tt>int</tt>, returning an <tt>int</tt><br/>
836 <a href="#t_pointer">Pointer</a> to a function that takes an
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]837 <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]838 returning <tt>float</tt>.<br/>
839 A vararg function that takes at least one <a href="#t_pointer">pointer</a>
840 to <tt>sbyte</tt> (signed char in C), which returns an integer. This is
841 the signature for <tt>printf</tt> in LLVM.<br/>
842 </td>
843 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]844</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]845
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]846</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]847<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]848<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]849<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]850<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]851<p>The structure type is used to represent a collection of data members
852together in memory. The packing of the field types is defined to match
853the ABI of the underlying processor. The elements of a structure may
854be any type that has a size.</p>
855<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
856and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
857field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
858instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]859<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]860<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]861<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]862<table class="layout">
863 <tr class="layout">
864 <td class="left">
865 <tt>{ int, int, int }</tt><br/>
866 <tt>{ float, int (int) * }</tt><br/>
867 </td>
868 <td class="left">
869 a triple of three <tt>int</tt> values<br/>
870 A pair, where the first element is a <tt>float</tt> and the second element
871 is a <a href="#t_pointer">pointer</a> to a <a href="#t_function">function</a>
872 that takes an <tt>int</tt>, returning an <tt>int</tt>.<br/>
873 </td>
874 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]875</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]876</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]877
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]878<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]879<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]880<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]881<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]882<p>As in many languages, the pointer type represents a pointer or
883reference to another object, which must live in memory.</p>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]884<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]885<pre> &lt;type&gt; *<br></pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]886<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]887<table class="layout">
888 <tr class="layout">
889 <td class="left">
890 <tt>[4x int]*</tt><br/>
891 <tt>int (int *) *</tt><br/>
892 </td>
893 <td class="left">
894 A <a href="#t_pointer">pointer</a> to <a href="#t_array">array</a> of
895 four <tt>int</tt> values<br/>
896 A <a href="#t_pointer">pointer</a> to a <a
Chris Lattnera977c482005-02-19 02:22:14 +0000[diff] [blame]897 href="#t_function">function</a> that takes an <tt>int*</tt>, returning an
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]898 <tt>int</tt>.<br/>
899 </td>
900 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]901</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]902</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]903
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]904<!-- _______________________________________________________________________ -->
905<div class="doc_subsubsection"> <a name="t_packed">Packed Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]906<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]907
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]908<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]909
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]910<p>A packed type is a simple derived type that represents a vector
911of elements. Packed types are used when multiple primitive data
912are operated in parallel using a single instruction (SIMD).
913A packed type requires a size (number of
Chris Lattnerb8d172f2005-11-10 01:44:22 +0000[diff] [blame]914elements) and an underlying primitive data type. Vectors must have a power
915of two length (1, 2, 4, 8, 16 ...). Packed types are
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]916considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]917
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]918<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]919
920<pre>
921 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
922</pre>
923
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]924<p>The number of elements is a constant integer value; elementtype may
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]925be any integral or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]926
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]927<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]928
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]929<table class="layout">
930 <tr class="layout">
931 <td class="left">
932 <tt>&lt;4 x int&gt;</tt><br/>
933 <tt>&lt;8 x float&gt;</tt><br/>
934 <tt>&lt;2 x uint&gt;</tt><br/>
935 </td>
936 <td class="left">
937 Packed vector of 4 integer values.<br/>
938 Packed vector of 8 floating-point values.<br/>
939 Packed vector of 2 unsigned integer values.<br/>
940 </td>
941 </tr>
942</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]943</div>
944
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]945<!-- _______________________________________________________________________ -->
946<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
947<div class="doc_text">
948
949<h5>Overview:</h5>
950
951<p>Opaque types are used to represent unknown types in the system. This
952corresponds (for example) to the C notion of a foward declared structure type.
953In LLVM, opaque types can eventually be resolved to any type (not just a
954structure type).</p>
955
956<h5>Syntax:</h5>
957
958<pre>
959 opaque
960</pre>
961
962<h5>Examples:</h5>
963
964<table class="layout">
965 <tr class="layout">
966 <td class="left">
967 <tt>opaque</tt>
968 </td>
969 <td class="left">
970 An opaque type.<br/>
971 </td>
972 </tr>
973</table>
974</div>
975
976
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]977<!-- *********************************************************************** -->
978<div class="doc_section"> <a name="constants">Constants</a> </div>
979<!-- *********************************************************************** -->
980
981<div class="doc_text">
982
983<p>LLVM has several different basic types of constants. This section describes
984them all and their syntax.</p>
985
986</div>
987
988<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]989<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]990
991<div class="doc_text">
992
993<dl>
994 <dt><b>Boolean constants</b></dt>
995
996 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
997 constants of the <tt><a href="#t_primitive">bool</a></tt> type.
998 </dd>
999
1000 <dt><b>Integer constants</b></dt>
1001
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1002 <dd>Standard integers (such as '4') are constants of the <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1003 href="#t_integer">integer</a> type. Negative numbers may be used with signed
1004 integer types.
1005 </dd>
1006
1007 <dt><b>Floating point constants</b></dt>
1008
1009 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1010 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1011 notation (see below). Floating point constants must have a <a
1012 href="#t_floating">floating point</a> type. </dd>
1013
1014 <dt><b>Null pointer constants</b></dt>
1015
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1016 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1017 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1018
1019</dl>
1020
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1021<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1022of floating point constants. For example, the form '<tt>double
10230x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
10244.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1025(and the only time that they are generated by the disassembler) is when a
1026floating point constant must be emitted but it cannot be represented as a
1027decimal floating point number. For example, NaN's, infinities, and other
1028special values are represented in their IEEE hexadecimal format so that
1029assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1030
1031</div>
1032
1033<!-- ======================================================================= -->
1034<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1035</div>
1036
1037<div class="doc_text">
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1038<p>Aggregate constants arise from aggregation of simple constants
1039and smaller aggregate constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1040
1041<dl>
1042 <dt><b>Structure constants</b></dt>
1043
1044 <dd>Structure constants are represented with notation similar to structure
1045 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1046 (<tt>{}</tt>)). For example: "<tt>{ int 4, float 17.0, int* %G }</tt>",
1047 where "<tt>%G</tt>" is declared as "<tt>%G = external global int</tt>". Structure constants
1048 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1049 types of elements must match those specified by the type.
1050 </dd>
1051
1052 <dt><b>Array constants</b></dt>
1053
1054 <dd>Array constants are represented with notation similar to array type
1055 definitions (a comma separated list of elements, surrounded by square brackets
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1056 (<tt>[]</tt>)). For example: "<tt>[ int 42, int 11, int 74 ]</tt>". Array
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1057 constants must have <a href="#t_array">array type</a>, and the number and
1058 types of elements must match those specified by the type.
1059 </dd>
1060
1061 <dt><b>Packed constants</b></dt>
1062
1063 <dd>Packed constants are represented with notation similar to packed type
1064 definitions (a comma separated list of elements, surrounded by
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1065 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]1066 int 11, int 74, int 100 &gt;</tt>". Packed constants must have <a
1067 href="#t_packed">packed type</a>, and the number and types of elements must
1068 match those specified by the type.
1069 </dd>
1070
1071 <dt><b>Zero initialization</b></dt>
1072
1073 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1074 value to zero of <em>any</em> type, including scalar and aggregate types.
1075 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]1076 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1077 initializers.
1078 </dd>
1079</dl>
1080
1081</div>
1082
1083<!-- ======================================================================= -->
1084<div class="doc_subsection">
1085 <a name="globalconstants">Global Variable and Function Addresses</a>
1086</div>
1087
1088<div class="doc_text">
1089
1090<p>The addresses of <a href="#globalvars">global variables</a> and <a
1091href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1092constants. These constants are explicitly referenced when the <a
1093href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1094href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1095file:</p>
1096
1097<pre>
1098 %X = global int 17
1099 %Y = global int 42
1100 %Z = global [2 x int*] [ int* %X, int* %Y ]
1101</pre>
1102
1103</div>
1104
1105<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1106<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1107<div class="doc_text">
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1108 <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]1109 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1110 a constant is permitted.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1111
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1112 <p>Undefined values indicate to the compiler that the program is well defined
1113 no matter what value is used, giving the compiler more freedom to optimize.
1114 </p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1115</div>
1116
1117<!-- ======================================================================= -->
1118<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1119</div>
1120
1121<div class="doc_text">
1122
1123<p>Constant expressions are used to allow expressions involving other constants
1124to be used as constants. Constant expressions may be of any <a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1125href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1126that does not have side effects (e.g. load and call are not supported). The
1127following is the syntax for constant expressions:</p>
1128
1129<dl>
1130 <dt><b><tt>cast ( CST to TYPE )</tt></b></dt>
1131
1132 <dd>Cast a constant to another type.</dd>
1133
1134 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1135
1136 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1137 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1138 instruction, the index list may have zero or more indexes, which are required
1139 to make sense for the type of "CSTPTR".</dd>
1140
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1141 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1142
1143 <dd>Perform the <a href="#i_select">select operation</a> on
1144 constants.
1145
1146 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1147
1148 <dd>Perform the <a href="#i_extractelement">extractelement
1149 operation</a> on constants.
1150
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1151 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1152
1153 <dd>Perform the <a href="#i_insertelement">insertelement
1154 operation</a> on constants.
1155
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1156
1157 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1158
1159 <dd>Perform the <a href="#i_shufflevector">shufflevector
1160 operation</a> on constants.
1161
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1162 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1163
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1164 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1165 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1166 binary</a> operations. The constraints on operands are the same as those for
1167 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1168 values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1169</dl>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1170</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]1171
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1172<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1173<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1174<!-- *********************************************************************** -->
1175
1176<!-- ======================================================================= -->
1177<div class="doc_subsection">
1178<a name="inlineasm">Inline Assembler Expressions</a>
1179</div>
1180
1181<div class="doc_text">
1182
1183<p>
1184LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1185Module-Level Inline Assembly</a>) through the use of a special value. This
1186value represents the inline assembler as a string (containing the instructions
1187to emit), a list of operand constraints (stored as a string), and a flag that
1188indicates whether or not the inline asm expression has side effects. An example
1189inline assembler expression is:
1190</p>
1191
1192<pre>
1193 int(int) asm "bswap $0", "=r,r"
1194</pre>
1195
1196<p>
1197Inline assembler expressions may <b>only</b> be used as the callee operand of
1198a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1199</p>
1200
1201<pre>
1202 %X = call int asm "<a href="#i_bswap">bswap</a> $0", "=r,r"(int %Y)
1203</pre>
1204
1205<p>
1206Inline asms with side effects not visible in the constraint list must be marked
1207as having side effects. This is done through the use of the
1208'<tt>sideeffect</tt>' keyword, like so:
1209</p>
1210
1211<pre>
1212 call void asm sideeffect "eieio", ""()
1213</pre>
1214
1215<p>TODO: The format of the asm and constraints string still need to be
1216documented here. Constraints on what can be done (e.g. duplication, moving, etc
1217need to be documented).
1218</p>
1219
1220</div>
1221
1222<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1223<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1224<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1225
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1226<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1227
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1228<p>The LLVM instruction set consists of several different
1229classifications of instructions: <a href="#terminators">terminator
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1230instructions</a>, <a href="#binaryops">binary instructions</a>,
1231<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1232 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1233instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1234
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1235</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1236
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1237<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1238<div class="doc_subsection"> <a name="terminators">Terminator
1239Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1240
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1241<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1242
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1243<p>As mentioned <a href="#functionstructure">previously</a>, every
1244basic block in a program ends with a "Terminator" instruction, which
1245indicates which block should be executed after the current block is
1246finished. These terminator instructions typically yield a '<tt>void</tt>'
1247value: they produce control flow, not values (the one exception being
1248the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1249<p>There are six different terminator instructions: the '<a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1250 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1251instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1252the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1253 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1254 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1255
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1256</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1257
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1258<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1259<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1260Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1261<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1262<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1263<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]1264 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1265</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1266<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1267<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1268value) from a function back to the caller.</p>
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]1269<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1270returns a value and then causes control flow, and one that just causes
1271control flow to occur.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1272<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1273<p>The '<tt>ret</tt>' instruction may return any '<a
1274 href="#t_firstclass">first class</a>' type. Notice that a function is
1275not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
1276instruction inside of the function that returns a value that does not
1277match the return type of the function.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1278<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1279<p>When the '<tt>ret</tt>' instruction is executed, control flow
1280returns back to the calling function's context. If the caller is a "<a
John Criswellfa081872004-06-25 15:16:57 +0000[diff] [blame]1281 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1282the instruction after the call. If the caller was an "<a
1283 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1284at the beginning of the "normal" destination block. If the instruction
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1285returns a value, that value shall set the call or invoke instruction's
1286return value.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1287<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1288<pre> ret int 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1289 ret void <i>; Return from a void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1290</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1291</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1292<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1293<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1294<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1295<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1296<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]1297</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1298<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1299<p>The '<tt>br</tt>' instruction is used to cause control flow to
1300transfer to a different basic block in the current function. There are
1301two forms of this instruction, corresponding to a conditional branch
1302and an unconditional branch.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1303<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1304<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
1305single '<tt>bool</tt>' value and two '<tt>label</tt>' values. The
1306unconditional form of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>'
1307value as a target.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1308<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1309<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>bool</tt>'
1310argument is evaluated. If the value is <tt>true</tt>, control flows
1311to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1312control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1313<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1314<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
1315 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]1316</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1317<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1318<div class="doc_subsubsection">
1319 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1320</div>
1321
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1322<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1323<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1324
1325<pre>
1326 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1327</pre>
1328
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1329<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1330
1331<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1332several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1333instruction, allowing a branch to occur to one of many possible
1334destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1335
1336
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1337<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1338
1339<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1340comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1341an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1342table is not allowed to contain duplicate constant entries.</p>
1343
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1344<h5>Semantics:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1345
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1346<p>The <tt>switch</tt> instruction specifies a table of values and
1347destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1348table is searched for the given value. If the value is found, control flow is
1349transfered to the corresponding destination; otherwise, control flow is
1350transfered to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1351
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1352<h5>Implementation:</h5>
1353
1354<p>Depending on properties of the target machine and the particular
1355<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1356ways. For example, it could be generated as a series of chained conditional
1357branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1358
1359<h5>Example:</h5>
1360
1361<pre>
1362 <i>; Emulate a conditional br instruction</i>
1363 %Val = <a href="#i_cast">cast</a> bool %value to int
1364 switch int %Val, label %truedest [int 0, label %falsedest ]
1365
1366 <i>; Emulate an unconditional br instruction</i>
1367 switch uint 0, label %dest [ ]
1368
1369 <i>; Implement a jump table:</i>
1370 switch uint %val, label %otherwise [ uint 0, label %onzero
1371 uint 1, label %onone
1372 uint 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1373</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1374</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1375
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1376<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1377<div class="doc_subsubsection">
1378 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1379</div>
1380
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1381<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1382
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1383<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1384
1385<pre>
1386 &lt;result&gt; = invoke [<a href="#callingconv">cconv</a>] &lt;ptr to function ty&gt; %&lt;function ptr val&gt;(&lt;function args&gt;)
Chris Lattner76b8a332006-05-14 18:23:06 +0000[diff] [blame]1387 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1388</pre>
1389
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1390<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1391
1392<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1393function, with the possibility of control flow transfer to either the
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1394'<tt>normal</tt>' label or the
1395'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1396"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1397"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1398href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
1399continued at the dynamically nearest "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1400
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1401<h5>Arguments:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1402
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1403<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1404
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1405<ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1406 <li>
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1407 The optional "cconv" marker indicates which <a href="callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1408 convention</a> the call should use. If none is specified, the call defaults
1409 to using C calling conventions.
1410 </li>
1411 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1412 function value being invoked. In most cases, this is a direct function
1413 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1414 an arbitrary pointer to function value.
1415 </li>
1416
1417 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1418 function to be invoked. </li>
1419
1420 <li>'<tt>function args</tt>': argument list whose types match the function
1421 signature argument types. If the function signature indicates the function
1422 accepts a variable number of arguments, the extra arguments can be
1423 specified. </li>
1424
1425 <li>'<tt>normal label</tt>': the label reached when the called function
1426 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1427
1428 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1429 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1430
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1431</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1432
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1433<h5>Semantics:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1434
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1435<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1436href="#i_call">call</a></tt>' instruction in most regards. The primary
1437difference is that it establishes an association with a label, which is used by
1438the runtime library to unwind the stack.</p>
1439
1440<p>This instruction is used in languages with destructors to ensure that proper
1441cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1442exception. Additionally, this is important for implementation of
1443'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1444
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1445<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1446<pre>
1447 %retval = invoke int %Test(int 15) to label %Continue
Chris Lattner76b8a332006-05-14 18:23:06 +0000[diff] [blame]1448 unwind label %TestCleanup <i>; {int}:retval set</i>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1449 %retval = invoke <a href="#callingconv">coldcc</a> int %Test(int 15) to label %Continue
Chris Lattner76b8a332006-05-14 18:23:06 +0000[diff] [blame]1450 unwind label %TestCleanup <i>; {int}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1451</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1452</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1453
1454
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1455<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1456
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1457<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1458Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1459
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1460<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1461
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1462<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1463<pre>
1464 unwind
1465</pre>
1466
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1467<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1468
1469<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
1470at the first callee in the dynamic call stack which used an <a
1471href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
1472primarily used to implement exception handling.</p>
1473
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1474<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1475
1476<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
1477immediately halt. The dynamic call stack is then searched for the first <a
1478href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
1479execution continues at the "exceptional" destination block specified by the
1480<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
1481dynamic call chain, undefined behavior results.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1482</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1483
1484<!-- _______________________________________________________________________ -->
1485
1486<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
1487Instruction</a> </div>
1488
1489<div class="doc_text">
1490
1491<h5>Syntax:</h5>
1492<pre>
1493 unreachable
1494</pre>
1495
1496<h5>Overview:</h5>
1497
1498<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
1499instruction is used to inform the optimizer that a particular portion of the
1500code is not reachable. This can be used to indicate that the code after a
1501no-return function cannot be reached, and other facts.</p>
1502
1503<h5>Semantics:</h5>
1504
1505<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
1506</div>
1507
1508
1509
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1510<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1511<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1512<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1513<p>Binary operators are used to do most of the computation in a
1514program. They require two operands, execute an operation on them, and
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1515produce a single value. The operands might represent
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1516multiple data, as is the case with the <a href="#t_packed">packed</a> data type.
1517The result value of a binary operator is not
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1518necessarily the same type as its operands.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1519<p>There are several different binary operators:</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1520</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1521<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1522<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
1523Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1524<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1525<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1526<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]1527</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1528<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1529<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1530<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1531<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1532 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
1533 This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1534Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1535<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1536<p>The value produced is the integer or floating point sum of the two
1537operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1538<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1539<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]1540</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1541</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1542<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1543<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
1544Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1545<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1546<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1547<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]1548</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1549<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1550<p>The '<tt>sub</tt>' instruction returns the difference of its two
1551operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1552<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
1553instruction present in most other intermediate representations.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1554<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1555<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1556 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1557values.
1558This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1559Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1560<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1561<p>The value produced is the integer or floating point difference of
1562the two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1563<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1564<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]1565 &lt;result&gt; = sub int 0, %val <i>; yields {int}:result = -%var</i>
1566</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1567</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1568<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1569<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
1570Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1571<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1572<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1573<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]1574</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1575<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1576<p>The '<tt>mul</tt>' instruction returns the product of its two
1577operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1578<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1579<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1580 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1581values.
1582This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1583Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1584<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1585<p>The value produced is the integer or floating point product of the
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1586two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1587<p>There is no signed vs unsigned multiplication. The appropriate
1588action is taken based on the type of the operand.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1589<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1590<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]1591</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1592</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1593<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1594<div class="doc_subsubsection"> <a name="i_div">'<tt>div</tt>'
1595Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1596<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1597<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1598<pre> &lt;result&gt; = div &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1599</pre>
1600<h5>Overview:</h5>
1601<p>The '<tt>div</tt>' instruction returns the quotient of its two
1602operands.</p>
1603<h5>Arguments:</h5>
1604<p>The two arguments to the '<tt>div</tt>' instruction must be either <a
1605 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1606values.
1607This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1608Both arguments must have identical types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1609<h5>Semantics:</h5>
1610<p>The value produced is the integer or floating point quotient of the
1611two operands.</p>
1612<h5>Example:</h5>
1613<pre> &lt;result&gt; = div int 4, %var <i>; yields {int}:result = 4 / %var</i>
1614</pre>
1615</div>
1616<!-- _______________________________________________________________________ -->
1617<div class="doc_subsubsection"> <a name="i_rem">'<tt>rem</tt>'
1618Instruction</a> </div>
1619<div class="doc_text">
1620<h5>Syntax:</h5>
1621<pre> &lt;result&gt; = rem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1622</pre>
1623<h5>Overview:</h5>
1624<p>The '<tt>rem</tt>' instruction returns the remainder from the
1625division of its two operands.</p>
1626<h5>Arguments:</h5>
1627<p>The two arguments to the '<tt>rem</tt>' instruction must be either <a
1628 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1629values.
1630This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1631Both arguments must have identical types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1632<h5>Semantics:</h5>
1633<p>This returns the <i>remainder</i> of a division (where the result
1634has the same sign as the divisor), not the <i>modulus</i> (where the
1635result has the same sign as the dividend) of a value. For more
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1636information about the difference, see <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1637 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
1638Math Forum</a>.</p>
1639<h5>Example:</h5>
1640<pre> &lt;result&gt; = rem int 4, %var <i>; yields {int}:result = 4 % %var</i>
1641</pre>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]1642
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1643</div>
1644<!-- _______________________________________________________________________ -->
1645<div class="doc_subsubsection"> <a name="i_setcc">'<tt>set<i>cc</i></tt>'
1646Instructions</a> </div>
1647<div class="doc_text">
1648<h5>Syntax:</h5>
1649<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]1650 &lt;result&gt; = setne &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1651 &lt;result&gt; = setlt &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1652 &lt;result&gt; = setgt &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1653 &lt;result&gt; = setle &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1654 &lt;result&gt; = setge &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1655</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1656<h5>Overview:</h5>
1657<p>The '<tt>set<i>cc</i></tt>' family of instructions returns a boolean
1658value based on a comparison of their two operands.</p>
1659<h5>Arguments:</h5>
1660<p>The two arguments to the '<tt>set<i>cc</i></tt>' instructions must
1661be of <a href="#t_firstclass">first class</a> type (it is not possible
1662to compare '<tt>label</tt>'s, '<tt>array</tt>'s, '<tt>structure</tt>'
1663or '<tt>void</tt>' values, etc...). Both arguments must have identical
1664types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1665<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1666<p>The '<tt>seteq</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1667value if both operands are equal.<br>
1668The '<tt>setne</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1669value if both operands are unequal.<br>
1670The '<tt>setlt</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1671value if the first operand is less than the second operand.<br>
1672The '<tt>setgt</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1673value if the first operand is greater than the second operand.<br>
1674The '<tt>setle</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1675value if the first operand is less than or equal to the second operand.<br>
1676The '<tt>setge</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1677value if the first operand is greater than or equal to the second
1678operand.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1679<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1680<pre> &lt;result&gt; = seteq int 4, 5 <i>; yields {bool}:result = false</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1681 &lt;result&gt; = setne float 4, 5 <i>; yields {bool}:result = true</i>
1682 &lt;result&gt; = setlt uint 4, 5 <i>; yields {bool}:result = true</i>
1683 &lt;result&gt; = setgt sbyte 4, 5 <i>; yields {bool}:result = false</i>
1684 &lt;result&gt; = setle sbyte 4, 5 <i>; yields {bool}:result = true</i>
1685 &lt;result&gt; = setge sbyte 4, 5 <i>; yields {bool}:result = false</i>
1686</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1687</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]1688
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1689<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1690<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
1691Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1692<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1693<p>Bitwise binary operators are used to do various forms of
1694bit-twiddling in a program. They are generally very efficient
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1695instructions and can commonly be strength reduced from other
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1696instructions. They require two operands, execute an operation on them,
1697and produce a single value. The resulting value of the bitwise binary
1698operators is always the same type as its first operand.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1699</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1700<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1701<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
1702Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1703<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1704<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1705<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]1706</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1707<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1708<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
1709its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1710<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1711<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1712 href="#t_integral">integral</a> values. Both arguments must have
1713identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1714<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1715<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1716<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1717<div style="align: center">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1718<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1719 <tbody>
1720 <tr>
1721 <td>In0</td>
1722 <td>In1</td>
1723 <td>Out</td>
1724 </tr>
1725 <tr>
1726 <td>0</td>
1727 <td>0</td>
1728 <td>0</td>
1729 </tr>
1730 <tr>
1731 <td>0</td>
1732 <td>1</td>
1733 <td>0</td>
1734 </tr>
1735 <tr>
1736 <td>1</td>
1737 <td>0</td>
1738 <td>0</td>
1739 </tr>
1740 <tr>
1741 <td>1</td>
1742 <td>1</td>
1743 <td>1</td>
1744 </tr>
1745 </tbody>
1746</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1747</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1748<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1749<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]1750 &lt;result&gt; = and int 15, 40 <i>; yields {int}:result = 8</i>
1751 &lt;result&gt; = and int 4, 8 <i>; yields {int}:result = 0</i>
1752</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1753</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1754<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1755<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1756<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1757<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1758<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]1759</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1760<h5>Overview:</h5>
1761<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
1762or of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1763<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1764<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1765 href="#t_integral">integral</a> values. Both arguments must have
1766identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1767<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1768<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1769<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1770<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1771<table border="1" cellspacing="0" cellpadding="4">
1772 <tbody>
1773 <tr>
1774 <td>In0</td>
1775 <td>In1</td>
1776 <td>Out</td>
1777 </tr>
1778 <tr>
1779 <td>0</td>
1780 <td>0</td>
1781 <td>0</td>
1782 </tr>
1783 <tr>
1784 <td>0</td>
1785 <td>1</td>
1786 <td>1</td>
1787 </tr>
1788 <tr>
1789 <td>1</td>
1790 <td>0</td>
1791 <td>1</td>
1792 </tr>
1793 <tr>
1794 <td>1</td>
1795 <td>1</td>
1796 <td>1</td>
1797 </tr>
1798 </tbody>
1799</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1800</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1801<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1802<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]1803 &lt;result&gt; = or int 15, 40 <i>; yields {int}:result = 47</i>
1804 &lt;result&gt; = or int 4, 8 <i>; yields {int}:result = 12</i>
1805</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1806</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1807<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1808<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
1809Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1810<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1811<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1812<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]1813</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1814<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1815<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
1816or of its two operands. The <tt>xor</tt> is used to implement the
1817"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1818<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1819<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1820 href="#t_integral">integral</a> values. Both arguments must have
1821identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1822<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1823<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1824<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1825<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1826<table border="1" cellspacing="0" cellpadding="4">
1827 <tbody>
1828 <tr>
1829 <td>In0</td>
1830 <td>In1</td>
1831 <td>Out</td>
1832 </tr>
1833 <tr>
1834 <td>0</td>
1835 <td>0</td>
1836 <td>0</td>
1837 </tr>
1838 <tr>
1839 <td>0</td>
1840 <td>1</td>
1841 <td>1</td>
1842 </tr>
1843 <tr>
1844 <td>1</td>
1845 <td>0</td>
1846 <td>1</td>
1847 </tr>
1848 <tr>
1849 <td>1</td>
1850 <td>1</td>
1851 <td>0</td>
1852 </tr>
1853 </tbody>
1854</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1855</div>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1856<p> </p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1857<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1858<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]1859 &lt;result&gt; = xor int 15, 40 <i>; yields {int}:result = 39</i>
1860 &lt;result&gt; = xor int 4, 8 <i>; yields {int}:result = 12</i>
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1861 &lt;result&gt; = xor int %V, -1 <i>; yields {int}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1862</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1863</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1864<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1865<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
1866Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1867<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1868<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1869<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]1870</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1871<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1872<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
1873the left a specified number of bits.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1874<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1875<p>The first argument to the '<tt>shl</tt>' instruction must be an <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1876 href="#t_integer">integer</a> type. The second argument must be an '<tt>ubyte</tt>'
1877type.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1878<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1879<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]1880<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1881<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]1882 &lt;result&gt; = shl int 4, ubyte 2 <i>; yields {int}:result = 16</i>
1883 &lt;result&gt; = shl int 1, ubyte 10 <i>; yields {int}:result = 1024</i>
1884</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1885</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1886<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1887<div class="doc_subsubsection"> <a name="i_shr">'<tt>shr</tt>'
1888Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1889<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1890<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1891<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]1892</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1893<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1894<p>The '<tt>shr</tt>' instruction returns the first operand shifted to
1895the right a specified number of bits.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1896<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1897<p>The first argument to the '<tt>shr</tt>' instruction must be an <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1898 href="#t_integer">integer</a> type. The second argument must be an '<tt>ubyte</tt>'
1899type.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1900<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1901<p>If the first argument is a <a href="#t_signed">signed</a> type, the
1902most significant bit is duplicated in the newly free'd bit positions.
1903If the first argument is unsigned, zero bits shall fill the empty
1904positions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1905<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1906<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]1907 &lt;result&gt; = shr uint 4, ubyte 1 <i>; yields {uint}:result = 2</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1908 &lt;result&gt; = shr int 4, ubyte 2 <i>; yields {int}:result = 1</i>
Chris Lattner8c6bb902003-06-18 21:30:51 +0000[diff] [blame]1909 &lt;result&gt; = shr sbyte 4, ubyte 3 <i>; yields {sbyte}:result = 0</i>
1910 &lt;result&gt; = shr sbyte -2, ubyte 1 <i>; yields {sbyte}:result = -1</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1911</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1912</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]1913
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1914<!-- ======================================================================= -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]1915<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]1916 <a name="vectorops">Vector Operations</a>
1917</div>
1918
1919<div class="doc_text">
1920
1921<p>LLVM supports several instructions to represent vector operations in a
1922target-independent manner. This instructions cover the element-access and
1923vector-specific operations needed to process vectors effectively. While LLVM
1924does directly support these vector operations, many sophisticated algorithms
1925will want to use target-specific intrinsics to take full advantage of a specific
1926target.</p>
1927
1928</div>
1929
1930<!-- _______________________________________________________________________ -->
1931<div class="doc_subsubsection">
1932 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
1933</div>
1934
1935<div class="doc_text">
1936
1937<h5>Syntax:</h5>
1938
1939<pre>
1940 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, uint &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
1941</pre>
1942
1943<h5>Overview:</h5>
1944
1945<p>
1946The '<tt>extractelement</tt>' instruction extracts a single scalar
1947element from a packed vector at a specified index.
1948</p>
1949
1950
1951<h5>Arguments:</h5>
1952
1953<p>
1954The first operand of an '<tt>extractelement</tt>' instruction is a
1955value of <a href="#t_packed">packed</a> type. The second operand is
1956an index indicating the position from which to extract the element.
1957The index may be a variable.</p>
1958
1959<h5>Semantics:</h5>
1960
1961<p>
1962The result is a scalar of the same type as the element type of
1963<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
1964<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
1965results are undefined.
1966</p>
1967
1968<h5>Example:</h5>
1969
1970<pre>
1971 %result = extractelement &lt;4 x int&gt; %vec, uint 0 <i>; yields int</i>
1972</pre>
1973</div>
1974
1975
1976<!-- _______________________________________________________________________ -->
1977<div class="doc_subsubsection">
1978 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
1979</div>
1980
1981<div class="doc_text">
1982
1983<h5>Syntax:</h5>
1984
1985<pre>
1986 &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>
1987</pre>
1988
1989<h5>Overview:</h5>
1990
1991<p>
1992The '<tt>insertelement</tt>' instruction inserts a scalar
1993element into a packed vector at a specified index.
1994</p>
1995
1996
1997<h5>Arguments:</h5>
1998
1999<p>
2000The first operand of an '<tt>insertelement</tt>' instruction is a
2001value of <a href="#t_packed">packed</a> type. The second operand is a
2002scalar value whose type must equal the element type of the first
2003operand. The third operand is an index indicating the position at
2004which to insert the value. The index may be a variable.</p>
2005
2006<h5>Semantics:</h5>
2007
2008<p>
2009The result is a packed vector of the same type as <tt>val</tt>. Its
2010element values are those of <tt>val</tt> except at position
2011<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2012exceeds the length of <tt>val</tt>, the results are undefined.
2013</p>
2014
2015<h5>Example:</h5>
2016
2017<pre>
2018 %result = insertelement &lt;4 x int&gt; %vec, int 1, uint 0 <i>; yields &lt;4 x int&gt;</i>
2019</pre>
2020</div>
2021
2022<!-- _______________________________________________________________________ -->
2023<div class="doc_subsubsection">
2024 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2025</div>
2026
2027<div class="doc_text">
2028
2029<h5>Syntax:</h5>
2030
2031<pre>
2032 &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>
2033</pre>
2034
2035<h5>Overview:</h5>
2036
2037<p>
2038The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2039from two input vectors, returning a vector of the same type.
2040</p>
2041
2042<h5>Arguments:</h5>
2043
2044<p>
2045The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2046with types that match each other and types that match the result of the
2047instruction. The third argument is a shuffle mask, which has the same number
2048of elements as the other vector type, but whose element type is always 'uint'.
2049</p>
2050
2051<p>
2052The shuffle mask operand is required to be a constant vector with either
2053constant integer or undef values.
2054</p>
2055
2056<h5>Semantics:</h5>
2057
2058<p>
2059The elements of the two input vectors are numbered from left to right across
2060both of the vectors. The shuffle mask operand specifies, for each element of
2061the result vector, which element of the two input registers the result element
2062gets. The element selector may be undef (meaning "don't care") and the second
2063operand may be undef if performing a shuffle from only one vector.
2064</p>
2065
2066<h5>Example:</h5>
2067
2068<pre>
2069 %result = shufflevector &lt;4 x int&gt; %v1, &lt;4 x int&gt; %v2,
2070 &lt;4 x uint&gt; &lt;uint 0, uint 4, uint 1, uint 5&gt; <i>; yields &lt;4 x int&gt;</i>
2071 %result = shufflevector &lt;4 x int&gt; %v1, &lt;4 x int&gt; undef,
2072 &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.
2073</pre>
2074</div>
2075
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]2076
2077<!-- _______________________________________________________________________ -->
2078<div class="doc_subsubsection"> <a name="i_vsetint">'<tt>vsetint</tt>'
2079Instruction</a> </div>
2080<div class="doc_text">
2081<h5>Syntax:</h5>
2082<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>
2083</pre>
2084
2085<h5>Overview:</h5>
2086
2087<p>The '<tt>vsetint</tt>' instruction takes two integer vectors and
2088returns a vector of boolean values representing, at each position, the
2089result of the comparison between the values at that position in the
2090two operands.</p>
2091
2092<h5>Arguments:</h5>
2093
2094<p>The arguments to a '<tt>vsetint</tt>' instruction are a comparison
2095operation and two value arguments. The value arguments must be of <a
2096href="#t_integral">integral</a> <a href="#t_packed">packed</a> type,
2097and they must have identical types. The operation argument must be
2098one of <tt>eq</tt>, <tt>ne</tt>, <tt>slt</tt>, <tt>sgt</tt>,
2099<tt>sle</tt>, <tt>sge</tt>, <tt>ult</tt>, <tt>ugt</tt>, <tt>ule</tt>,
2100<tt>uge</tt>, <tt>true</tt>, and <tt>false</tt>. The result is a
2101packed <tt>bool</tt> value with the same length as each operand.</p>
2102
2103<h5>Semantics:</h5>
2104
2105<p>The following table shows the semantics of '<tt>vsetint</tt>'. For
2106each position of the result, the comparison is done on the
2107corresponding positions of the two value arguments. Note that the
2108signedness of the comparison depends on the comparison opcode and
2109<i>not</i> on the signedness of the value operands. E.g., <tt>vsetint
2110slt <4 x unsigned> %x, %y</tt> does an elementwise <i>signed</i>
2111comparison of <tt>%x</tt> and <tt>%y</tt>.</p>
2112
2113<table border="1" cellspacing="0" cellpadding="4">
2114 <tbody>
2115 <tr><th>Operation</th><th>Result is true iff</th><th>Comparison is</th></tr>
2116 <tr><td><tt>eq</tt></td><td>var1 == var2</td><td>--</td></tr>
2117 <tr><td><tt>ne</tt></td><td>var1 != var2</td><td>--</td></tr>
2118 <tr><td><tt>slt</tt></td><td>var1 &lt; var2</td><td>signed</td></tr>
2119 <tr><td><tt>sgt</tt></td><td>var1 &gt; var2</td><td>signed</td></tr>
2120 <tr><td><tt>sle</tt></td><td>var1 &lt;= var2</td><td>signed</td></tr>
2121 <tr><td><tt>sge</tt></td><td>var1 &gt;= var2</td><td>signed</td></tr>
2122 <tr><td><tt>ult</tt></td><td>var1 &lt; var2</td><td>unsigned</td></tr>
2123 <tr><td><tt>ugt</tt></td><td>var1 &gt; var2</td><td>unsigned</td></tr>
2124 <tr><td><tt>ule</tt></td><td>var1 &lt;= var2</td><td>unsigned</td></tr>
2125 <tr><td><tt>uge</tt></td><td>var1 &gt;= var2</td><td>unsigned</td></tr>
2126 <tr><td><tt>true</tt></td><td>always</td><td>--</td></tr>
2127 <tr><td><tt>false</tt></td><td>never</td><td>--</td></tr>
2128 </tbody>
2129</table>
2130
2131<h5>Example:</h5>
2132<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>
2133 &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>
2134 &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>
2135 &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>
2136 &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>
2137 &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>
2138</pre>
2139</div>
2140
2141<!-- _______________________________________________________________________ -->
2142<div class="doc_subsubsection"> <a name="i_vsetfp">'<tt>vsetfp</tt>'
2143Instruction</a> </div>
2144<div class="doc_text">
2145<h5>Syntax:</h5>
2146<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>
2147</pre>
2148
2149<h5>Overview:</h5>
2150
2151<p>The '<tt>vsetfp</tt>' instruction takes two floating point vector
2152arguments and returns a vector of boolean values representing, at each
2153position, the result of the comparison between the values at that
2154position in the two operands.</p>
2155
2156<h5>Arguments:</h5>
2157
2158<p>The arguments to a '<tt>vsetfp</tt>' instruction are a comparison
2159operation and two value arguments. The value arguments must be of <a
2160href="t_floating">floating point</a> <a href="#t_packed">packed</a>
2161type, and they must have identical types. The operation argument must
2162be one of <tt>eq</tt>, <tt>ne</tt>, <tt>lt</tt>, <tt>gt</tt>,
2163<tt>le</tt>, <tt>ge</tt>, <tt>oeq</tt>, <tt>one</tt>, <tt>olt</tt>,
2164<tt>ogt</tt>, <tt>ole</tt>, <tt>oge</tt>, <tt>ueq</tt>, <tt>une</tt>,
2165<tt>ult</tt>, <tt>ugt</tt>, <tt>ule</tt>, <tt>uge</tt>, <tt>o</tt>,
2166<tt>u</tt>, <tt>true</tt>, and <tt>false</tt>. The result is a packed
2167<tt>bool</tt> value with the same length as each operand.</p>
2168
2169<h5>Semantics:</h5>
2170
2171<p>The following table shows the semantics of '<tt>vsetfp</tt>' for
2172floating point types. If either operand is a floating point Not a
2173Number (NaN) value, the operation is unordered, and the value in the
2174first column below is produced at that position. Otherwise, the
2175operation is ordered, and the value in the second column is
2176produced.</p>
2177
2178<table border="1" cellspacing="0" cellpadding="4">
2179 <tbody>
2180 <tr><th>Operation</th><th>If unordered<th>Otherwise true iff</th></tr>
2181 <tr><td><tt>eq</tt></td><td>undefined</td><td>var1 == var2</td></tr>
2182 <tr><td><tt>ne</tt></td><td>undefined</td><td>var1 != var2</td></tr>
2183 <tr><td><tt>lt</tt></td><td>undefined</td><td>var1 &lt; var2</td></tr>
2184 <tr><td><tt>gt</tt></td><td>undefined</td><td>var1 &gt; var2</td></tr>
2185 <tr><td><tt>le</tt></td><td>undefined</td><td>var1 &lt;= var2</td></tr>
2186 <tr><td><tt>ge</tt></td><td>undefined</td><td>var1 &gt;= var2</td></tr>
2187 <tr><td><tt>oeq</tt></td><td>false</td><td>var1 == var2</td></tr>
2188 <tr><td><tt>one</tt></td><td>false</td><td>var1 != var2</td></tr>
2189 <tr><td><tt>olt</tt></td><td>false</td><td>var1 &lt; var2</td></tr>
2190 <tr><td><tt>ogt</tt></td><td>false</td><td>var1 &gt; var2</td></tr>
2191 <tr><td><tt>ole</tt></td><td>false</td><td>var1 &lt;= var2</td></tr>
2192 <tr><td><tt>oge</tt></td><td>false</td><td>var1 &gt;= var2</td></tr>
2193 <tr><td><tt>ueq</tt></td><td>true</td><td>var1 == var2</td></tr>
2194 <tr><td><tt>une</tt></td><td>true</td><td>var1 != var2</td></tr>
2195 <tr><td><tt>ult</tt></td><td>true</td><td>var1 &lt; var2</td></tr>
2196 <tr><td><tt>ugt</tt></td><td>true</td><td>var1 &gt; var2</td></tr>
2197 <tr><td><tt>ule</tt></td><td>true</td><td>var1 &lt;= var2</td></tr>
2198 <tr><td><tt>uge</tt></td><td>true</td><td>var1 &gt;= var2</td></tr>
2199 <tr><td><tt>o</tt></td><td>false</td><td>always</td></tr>
2200 <tr><td><tt>u</tt></td><td>true</td><td>never</td></tr>
2201 <tr><td><tt>true</tt></td><td>true</td><td>always</td></tr>
2202 <tr><td><tt>false</tt></td><td>false</td><td>never</td></tr>
2203 </tbody>
2204</table>
2205
2206<h5>Example:</h5>
2207<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>
2208 &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>
2209 &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>
2210 &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>
2211 &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>
2212 &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>
2213</pre>
2214</div>
2215
2216<!-- _______________________________________________________________________ -->
2217<div class="doc_subsubsection">
2218 <a name="i_vselect">'<tt>vselect</tt>' Instruction</a>
2219</div>
2220
2221<div class="doc_text">
2222
2223<h5>Syntax:</h5>
2224
2225<pre>
2226 &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>
2227</pre>
2228
2229<h5>Overview:</h5>
2230
2231<p>
2232The '<tt>vselect</tt>' instruction chooses one value at each position
2233of a vector based on a condition.
2234</p>
2235
2236
2237<h5>Arguments:</h5>
2238
2239<p>
2240The '<tt>vselect</tt>' instruction requires a <a
2241href="#t_packed">packed</a> <tt>bool</tt> value indicating the
2242condition at each vector position, and two values of the same packed
2243type. All three operands must have the same length. The type of the
2244result is the same as the type of the two value operands.</p>
2245
2246<h5>Semantics:</h5>
2247
2248<p>
2249At each position where the <tt>bool</tt> vector is true, that position
2250of the result gets its value from the first value argument; otherwise,
2251it gets its value from the second value argument.
2252</p>
2253
2254<h5>Example:</h5>
2255
2256<pre>
2257 %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;,
2258 &lt;2 x ubyte&gt; &lt;ubyte 42, ubyte 42&gt; <i>; yields &lt;2 x ubyte&gt;:17, 42</i>
2259</pre>
2260</div>
2261
2262
2263
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2264<!-- ======================================================================= -->
2265<div class="doc_subsection">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2266 <a name="memoryops">Memory Access Operations</a>
2267</div>
2268
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2269<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2270
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2271<p>A key design point of an SSA-based representation is how it
2272represents memory. In LLVM, no memory locations are in SSA form, which
2273makes things very simple. This section describes how to read, write,
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2274allocate, and free memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2275
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2276</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2277
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2278<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2279<div class="doc_subsubsection">
2280 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2281</div>
2282
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2283<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2284
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2285<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2286
2287<pre>
2288 &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]2289</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2290
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2291<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2292
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2293<p>The '<tt>malloc</tt>' instruction allocates memory from the system
2294heap and returns a pointer to it.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2295
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2296<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2297
2298<p>The '<tt>malloc</tt>' instruction allocates
2299<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswell6e4ca612004-02-24 16:13:56 +0000[diff] [blame]2300bytes of memory from the operating system and returns a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2301appropriate type to the program. If "NumElements" is specified, it is the
2302number of elements allocated. If an alignment is specified, the value result
2303of the allocation is guaranteed to be aligned to at least that boundary. If
2304not specified, or if zero, the target can choose to align the allocation on any
2305convenient boundary.</p>
2306
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2307<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2308
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2309<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2310
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2311<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
2312a pointer is returned.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2313
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2314<h5>Example:</h5>
2315
2316<pre>
2317 %array = malloc [4 x ubyte ] <i>; yields {[%4 x ubyte]*}:array</i>
2318
2319 %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]2320 %array1 = malloc ubyte, uint 4 <i>; yields {ubyte*}:array1</i>
2321 %array2 = malloc [12 x ubyte], uint %size <i>; yields {[12 x ubyte]*}:array2</i>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2322 %array3 = malloc int, uint 4, align 1024 <i>; yields {int*}:array3</i>
2323 %array4 = malloc int, align 1024 <i>; yields {int*}:array4</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2324</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2325</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2326
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2327<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2328<div class="doc_subsubsection">
2329 <a name="i_free">'<tt>free</tt>' Instruction</a>
2330</div>
2331
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2332<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2333
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2334<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2335
2336<pre>
2337 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2338</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2339
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2340<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2341
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2342<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2343memory heap to be reallocated in the future.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2344
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2345<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2346
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2347<p>'<tt>value</tt>' shall be a pointer value that points to a value
2348that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
2349instruction.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2350
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2351<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2352
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2353<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2354after this instruction executes.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2355
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2356<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2357
2358<pre>
2359 %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]2360 free [4 x ubyte]* %array
2361</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2362</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2363
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2364<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2365<div class="doc_subsubsection">
2366 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
2367</div>
2368
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2369<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2370
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2371<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2372
2373<pre>
2374 &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]2375</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2376
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2377<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2378
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2379<p>The '<tt>alloca</tt>' instruction allocates memory on the current
2380stack frame of the procedure that is live until the current function
2381returns to its caller.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2382
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2383<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2384
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2385<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2386bytes of memory on the runtime stack, returning a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2387appropriate type to the program. If "NumElements" is specified, it is the
2388number of elements allocated. If an alignment is specified, the value result
2389of the allocation is guaranteed to be aligned to at least that boundary. If
2390not specified, or if zero, the target can choose to align the allocation on any
2391convenient boundary.</p>
2392
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2393<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2394
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2395<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2396
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2397<p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2398memory is automatically released when the function returns. The '<tt>alloca</tt>'
2399instruction is commonly used to represent automatic variables that must
2400have an address available. When the function returns (either with the <tt><a
John Criswelldae2e932005-05-12 16:55:34 +0000[diff] [blame]2401 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]2402instructions), the memory is reclaimed.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2403
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2404<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2405
2406<pre>
2407 %ptr = alloca int <i>; yields {int*}:ptr</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2408 %ptr = alloca int, uint 4 <i>; yields {int*}:ptr</i>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2409 %ptr = alloca int, uint 4, align 1024 <i>; yields {int*}:ptr</i>
2410 %ptr = alloca int, align 1024 <i>; yields {int*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2411</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2412</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2413
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2414<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2415<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
2416Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2417<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2418<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2419<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]2420<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2421<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2422<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2423<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2424address from which to load. The pointer must point to a <a
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]2425 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2426marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2427the number or order of execution of this <tt>load</tt> with other
2428volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
2429instructions. </p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2430<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2431<p>The location of memory pointed to is loaded.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2432<h5>Examples:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2433<pre> %ptr = <a href="#i_alloca">alloca</a> int <i>; yields {int*}:ptr</i>
2434 <a
2435 href="#i_store">store</a> int 3, int* %ptr <i>; yields {void}</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2436 %val = load int* %ptr <i>; yields {int}:val = int 3</i>
2437</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2438</div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2439<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2440<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
2441Instruction</a> </div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2442<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2443<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]2444 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]2445</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2446<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2447<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2448<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2449<p>There are two arguments to the '<tt>store</tt>' instruction: a value
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2450to 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]2451operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2452operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2453optimizer is not allowed to modify the number or order of execution of
2454this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
2455 href="#i_store">store</a></tt> instructions.</p>
2456<h5>Semantics:</h5>
2457<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
2458at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2459<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2460<pre> %ptr = <a href="#i_alloca">alloca</a> int <i>; yields {int*}:ptr</i>
2461 <a
2462 href="#i_store">store</a> int 3, int* %ptr <i>; yields {void}</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2463 %val = load int* %ptr <i>; yields {int}:val = int 3</i>
2464</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2465<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2466<div class="doc_subsubsection">
2467 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
2468</div>
2469
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2470<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2471<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2472<pre>
2473 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
2474</pre>
2475
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2476<h5>Overview:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2477
2478<p>
2479The '<tt>getelementptr</tt>' instruction is used to get the address of a
2480subelement of an aggregate data structure.</p>
2481
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2482<h5>Arguments:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2483
2484<p>This instruction takes a list of integer constants that indicate what
2485elements of the aggregate object to index to. The actual types of the arguments
2486provided depend on the type of the first pointer argument. The
2487'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2488levels of a structure or to a specific index in an array. When indexing into a
2489structure, only <tt>uint</tt>
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2490integer constants are allowed. When indexing into an array or pointer,
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2491<tt>int</tt> and <tt>long</tt> indexes are allowed of any sign.</p>
2492
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2493<p>For example, let's consider a C code fragment and how it gets
2494compiled to LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2495
2496<pre>
2497 struct RT {
2498 char A;
2499 int B[10][20];
2500 char C;
2501 };
2502 struct ST {
2503 int X;
2504 double Y;
2505 struct RT Z;
2506 };
2507
2508 int *foo(struct ST *s) {
2509 return &amp;s[1].Z.B[5][13];
2510 }
2511</pre>
2512
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2513<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2514
2515<pre>
2516 %RT = type { sbyte, [10 x [20 x int]], sbyte }
2517 %ST = type { int, double, %RT }
2518
Brian Gaeke7283e7c2004-07-02 21:08:14 +0000[diff] [blame]2519 implementation
2520
2521 int* %foo(%ST* %s) {
2522 entry:
2523 %reg = getelementptr %ST* %s, int 1, uint 2, uint 1, int 5, int 13
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2524 ret int* %reg
2525 }
2526</pre>
2527
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2528<h5>Semantics:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2529
2530<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2531on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]2532and <a href="#t_array">array</a> types require <tt>uint</tt>, <tt>int</tt>,
2533<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]2534types require <tt>uint</tt> <b>constants</b>.</p>
2535
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2536<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]2537type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ int, double, %RT
2538}</tt>' type, a structure. The second index indexes into the third element of
2539the structure, yielding a '<tt>%RT</tt>' = '<tt>{ sbyte, [10 x [20 x int]],
2540sbyte }</tt>' type, another structure. The third index indexes into the second
2541element of the structure, yielding a '<tt>[10 x [20 x int]]</tt>' type, an
2542array. The two dimensions of the array are subscripted into, yielding an
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2543'<tt>int</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2544to this element, thus computing a value of '<tt>int*</tt>' type.</p>
2545
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2546<p>Note that it is perfectly legal to index partially through a
2547structure, returning a pointer to an inner element. Because of this,
2548the LLVM code for the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2549
2550<pre>
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]2551 int* %foo(%ST* %s) {
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2552 %t1 = getelementptr %ST* %s, int 1 <i>; yields %ST*:%t1</i>
2553 %t2 = getelementptr %ST* %t1, int 0, uint 2 <i>; yields %RT*:%t2</i>
2554 %t3 = getelementptr %RT* %t2, int 0, uint 1 <i>; yields [10 x [20 x int]]*:%t3</i>
2555 %t4 = getelementptr [10 x [20 x int]]* %t3, int 0, int 5 <i>; yields [20 x int]*:%t4</i>
2556 %t5 = getelementptr [20 x int]* %t4, int 0, int 13 <i>; yields int*:%t5</i>
2557 ret int* %t5
2558 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2559</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2560
2561<p>Note that it is undefined to access an array out of bounds: array and
2562pointer indexes must always be within the defined bounds of the array type.
2563The one exception for this rules is zero length arrays. These arrays are
2564defined to be accessible as variable length arrays, which requires access
2565beyond the zero'th element.</p>
2566
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2567<h5>Example:</h5>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2568
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2569<pre>
2570 <i>; yields [12 x ubyte]*:aptr</i>
2571 %aptr = getelementptr {int, [12 x ubyte]}* %sptr, long 0, uint 1
2572</pre>
2573
2574</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2575<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2576<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2577<div class="doc_text">
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]2578<p>The instructions in this category are the "miscellaneous"
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2579instructions, which defy better classification.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2580</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2581<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2582<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
2583Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2584<div class="doc_text">
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2585<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2586<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]2587<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2588<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
2589the SSA graph representing the function.</p>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2590<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2591<p>The type of the incoming values are specified with the first type
2592field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
2593as arguments, with one pair for each predecessor basic block of the
2594current block. Only values of <a href="#t_firstclass">first class</a>
2595type may be used as the value arguments to the PHI node. Only labels
2596may be used as the label arguments.</p>
2597<p>There must be no non-phi instructions between the start of a basic
2598block and the PHI instructions: i.e. PHI instructions must be first in
2599a basic block.</p>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2600<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2601<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the
2602value specified by the parameter, depending on which basic block we
2603came from in the last <a href="#terminators">terminator</a> instruction.</p>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2604<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2605<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]2606</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2607
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2608<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2609<div class="doc_subsubsection">
2610 <a name="i_cast">'<tt>cast .. to</tt>' Instruction</a>
2611</div>
2612
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2613<div class="doc_text">
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2614
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2615<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2616
2617<pre>
2618 &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]2619</pre>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2620
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2621<h5>Overview:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2622
2623<p>
2624The '<tt>cast</tt>' instruction is used as the primitive means to convert
2625integers to floating point, change data type sizes, and break type safety (by
2626casting pointers).
2627</p>
2628
2629
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2630<h5>Arguments:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2631
2632<p>
2633The '<tt>cast</tt>' instruction takes a value to cast, which must be a first
2634class value, and a type to cast it to, which must also be a <a
2635href="#t_firstclass">first class</a> type.
2636</p>
2637
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2638<h5>Semantics:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2639
2640<p>
2641This instruction follows the C rules for explicit casts when determining how the
2642data being cast must change to fit in its new container.
2643</p>
2644
2645<p>
2646When casting to bool, any value that would be considered true in the context of
2647a C '<tt>if</tt>' condition is converted to the boolean '<tt>true</tt>' values,
2648all else are '<tt>false</tt>'.
2649</p>
2650
2651<p>
2652When extending an integral value from a type of one signness to another (for
2653example '<tt>sbyte</tt>' to '<tt>ulong</tt>'), the value is sign-extended if the
2654<b>source</b> value is signed, and zero-extended if the source value is
2655unsigned. <tt>bool</tt> values are always zero extended into either zero or
2656one.
2657</p>
2658
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2659<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2660
2661<pre>
2662 %X = cast int 257 to ubyte <i>; yields ubyte:1</i>
Chris Lattner7bae3952002-06-25 18:03:17 +0000[diff] [blame]2663 %Y = cast int 123 to bool <i>; yields bool:true</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2664</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2665</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2666
2667<!-- _______________________________________________________________________ -->
2668<div class="doc_subsubsection">
2669 <a name="i_select">'<tt>select</tt>' Instruction</a>
2670</div>
2671
2672<div class="doc_text">
2673
2674<h5>Syntax:</h5>
2675
2676<pre>
2677 &lt;result&gt; = select bool &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
2678</pre>
2679
2680<h5>Overview:</h5>
2681
2682<p>
2683The '<tt>select</tt>' instruction is used to choose one value based on a
2684condition, without branching.
2685</p>
2686
2687
2688<h5>Arguments:</h5>
2689
2690<p>
2691The '<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.
2692</p>
2693
2694<h5>Semantics:</h5>
2695
2696<p>
2697If the boolean condition evaluates to true, the instruction returns the first
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2698value argument; otherwise, it returns the second value argument.
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2699</p>
2700
2701<h5>Example:</h5>
2702
2703<pre>
2704 %X = select bool true, ubyte 17, ubyte 42 <i>; yields ubyte:17</i>
2705</pre>
2706</div>
2707
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]2708
2709<!-- _______________________________________________________________________ -->
2710<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2711 <a name="i_call">'<tt>call</tt>' Instruction</a>
2712</div>
2713
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2714<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2715
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2716<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2717<pre>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2718 &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]2719</pre>
2720
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2721<h5>Overview:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2722
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2723<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2724
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2725<h5>Arguments:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2726
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2727<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2728
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2729<ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2730 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2731 <p>The optional "tail" marker indicates whether the callee function accesses
2732 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2733 function call is eligible for tail call optimization. Note that calls may
2734 be marked "tail" even if they do not occur before a <a
2735 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2736 </li>
2737 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2738 <p>The optional "cconv" marker indicates which <a href="callingconv">calling
2739 convention</a> the call should use. If none is specified, the call defaults
2740 to using C calling conventions.
2741 </li>
2742 <li>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2743 <p>'<tt>ty</tt>': shall be the signature of the pointer to function value
2744 being invoked. The argument types must match the types implied by this
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2745 signature. This type can be omitted if the function is not varargs and
2746 if the function type does not return a pointer to a function.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2747 </li>
2748 <li>
2749 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
2750 be invoked. In most cases, this is a direct function invocation, but
2751 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2752 to function value.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2753 </li>
2754 <li>
2755 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencera7e302a2005-05-01 22:22:57 +0000[diff] [blame]2756 function signature argument types. All arguments must be of
2757 <a href="#t_firstclass">first class</a> type. If the function signature
2758 indicates the function accepts a variable number of arguments, the extra
2759 arguments can be specified.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2760 </li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2761</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2762
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2763<h5>Semantics:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2764
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2765<p>The '<tt>call</tt>' instruction is used to cause control flow to
2766transfer to a specified function, with its incoming arguments bound to
2767the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
2768instruction in the called function, control flow continues with the
2769instruction after the function call, and the return value of the
2770function is bound to the result argument. This is a simpler case of
2771the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2772
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2773<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2774
2775<pre>
2776 %retval = call int %test(int %argc)
2777 call int(sbyte*, ...) *%printf(sbyte* %msg, int 12, sbyte 42);
2778 %X = tail call int %foo()
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2779 %Y = tail call <a href="#callingconv">fastcc</a> int %foo()
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2780</pre>
2781
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2782</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2783
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2784<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2785<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]2786 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2787</div>
2788
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2789<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2790
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2791<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2792
2793<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2794 &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]2795</pre>
2796
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2797<h5>Overview:</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 is used to access arguments passed through
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2800the "variable argument" area of a function call. It is used to implement the
2801<tt>va_arg</tt> macro in C.</p>
2802
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2803<h5>Arguments:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2804
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2805<p>This instruction takes a <tt>va_list*</tt> value and the type of
2806the argument. It returns a value of the specified argument type and
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]2807increments the <tt>va_list</tt> to point to the next argument. Again, the
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2808actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2809
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2810<h5>Semantics:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2811
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2812<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
2813type from the specified <tt>va_list</tt> and causes the
2814<tt>va_list</tt> to point to the next argument. For more information,
2815see the variable argument handling <a href="#int_varargs">Intrinsic
2816Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2817
2818<p>It is legal for this instruction to be called in a function which does not
2819take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2820function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2821
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2822<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2823href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2824argument.</p>
2825
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2826<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2827
2828<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
2829
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2830</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2831
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2832<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2833<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
2834<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2835
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2836<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2837
2838<p>LLVM supports the notion of an "intrinsic function". These functions have
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2839well known names and semantics and are required to follow certain
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2840restrictions. Overall, these instructions represent an extension mechanism for
2841the LLVM language that does not require changing all of the transformations in
2842LLVM to add to the language (or the bytecode reader/writer, the parser,
2843etc...).</p>
2844
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2845<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
2846prefix is reserved in LLVM for intrinsic names; thus, functions may not be named
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2847this. Intrinsic functions must always be external functions: you cannot define
2848the body of intrinsic functions. Intrinsic functions may only be used in call
2849or invoke instructions: it is illegal to take the address of an intrinsic
2850function. Additionally, because intrinsic functions are part of the LLVM
2851language, it is required that they all be documented here if any are added.</p>
2852
2853
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2854<p>To learn how to add an intrinsic function, please see the <a
Chris Lattner590cff32005-05-11 03:35:57 +0000[diff] [blame]2855href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2856</p>
2857
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2858</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2859
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2860<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2861<div class="doc_subsection">
2862 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
2863</div>
2864
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2865<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2866
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2867<p>Variable argument support is defined in LLVM with the <a
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]2868 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2869intrinsic functions. These functions are related to the similarly
2870named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2871
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2872<p>All of these functions operate on arguments that use a
2873target-specific value type "<tt>va_list</tt>". The LLVM assembly
2874language reference manual does not define what this type is, so all
2875transformations should be prepared to handle intrinsics with any type
2876used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2877
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]2878<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2879instruction and the variable argument handling intrinsic functions are
2880used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2881
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2882<pre>
2883int %test(int %X, ...) {
2884 ; Initialize variable argument processing
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2885 %ap = alloca sbyte*
2886 call void %<a href="#i_va_start">llvm.va_start</a>(sbyte** %ap)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2887
2888 ; Read a single integer argument
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2889 %tmp = va_arg sbyte** %ap, int
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2890
2891 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2892 %aq = alloca sbyte*
Andrew Lenharthd0a4c622005-06-22 20:38:11 +0000[diff] [blame]2893 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]2894 call void %<a href="#i_va_end">llvm.va_end</a>(sbyte** %aq)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2895
2896 ; Stop processing of arguments.
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2897 call void %<a href="#i_va_end">llvm.va_end</a>(sbyte** %ap)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2898 ret int %tmp
2899}
2900</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2901</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2902
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2903<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2904<div class="doc_subsubsection">
2905 <a name="i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
2906</div>
2907
2908
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2909<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2910<h5>Syntax:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2911<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]2912<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2913<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
2914<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
2915href="#i_va_arg">va_arg</a></tt>.</p>
2916
2917<h5>Arguments:</h5>
2918
2919<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
2920
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2921<h5>Semantics:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2922
2923<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
2924macro available in C. In a target-dependent way, it initializes the
2925<tt>va_list</tt> element the argument points to, so that the next call to
2926<tt>va_arg</tt> will produce the first variable argument passed to the function.
2927Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
2928last argument of the function, the compiler can figure that out.</p>
2929
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2930</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2931
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2932<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2933<div class="doc_subsubsection">
2934 <a name="i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
2935</div>
2936
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2937<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2938<h5>Syntax:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2939<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]2940<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2941<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>&lt;arglist&gt;</tt>
2942which has been initialized previously with <tt><a href="#i_va_start">llvm.va_start</a></tt>
2943or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2944<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2945<p>The argument is a <tt>va_list</tt> to destroy.</p>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2946<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2947<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]2948macro available in C. In a target-dependent way, it destroys the <tt>va_list</tt>.
2949Calls to <a href="#i_va_start"><tt>llvm.va_start</tt></a> and <a
2950 href="#i_va_copy"><tt>llvm.va_copy</tt></a> must be matched exactly
2951with calls to <tt>llvm.va_end</tt>.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2952</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2953
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2954<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2955<div class="doc_subsubsection">
2956 <a name="i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
2957</div>
2958
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2959<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2960
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2961<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2962
2963<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2964 declare void %llvm.va_copy(&lt;va_list&gt;* &lt;destarglist&gt;,
Andrew Lenharthd0a4c622005-06-22 20:38:11 +0000[diff] [blame]2965 &lt;va_list&gt;* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2966</pre>
2967
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2968<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2969
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2970<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position from
2971the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2972
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2973<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2974
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2975<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]2976The 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]2977
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2978
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2979<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2980
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2981<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt> macro
2982available in C. In a target-dependent way, it copies the source
2983<tt>va_list</tt> element into the destination list. This intrinsic is necessary
2984because 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]2985arbitrarily complex and require memory allocation, for example.</p>
2986
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2987</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2988
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2989<!-- ======================================================================= -->
2990<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2991 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
2992</div>
2993
2994<div class="doc_text">
2995
2996<p>
2997LLVM support for <a href="GarbageCollection.html">Accurate Garbage
2998Collection</a> requires the implementation and generation of these intrinsics.
2999These intrinsics allow identification of <a href="#i_gcroot">GC roots on the
3000stack</a>, as well as garbage collector implementations that require <a
3001href="#i_gcread">read</a> and <a href="#i_gcwrite">write</a> barriers.
3002Front-ends for type-safe garbage collected languages should generate these
3003intrinsics to make use of the LLVM garbage collectors. For more details, see <a
3004href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
3005</p>
3006</div>
3007
3008<!-- _______________________________________________________________________ -->
3009<div class="doc_subsubsection">
3010 <a name="i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
3011</div>
3012
3013<div class="doc_text">
3014
3015<h5>Syntax:</h5>
3016
3017<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]3018 declare void %llvm.gcroot(&lt;ty&gt;** %ptrloc, &lt;ty2&gt;* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3019</pre>
3020
3021<h5>Overview:</h5>
3022
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]3023<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]3024the code generator, and allows some metadata to be associated with it.</p>
3025
3026<h5>Arguments:</h5>
3027
3028<p>The first argument specifies the address of a stack object that contains the
3029root pointer. The second pointer (which must be either a constant or a global
3030value address) contains the meta-data to be associated with the root.</p>
3031
3032<h5>Semantics:</h5>
3033
3034<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
3035location. At compile-time, the code generator generates information to allow
3036the runtime to find the pointer at GC safe points.
3037</p>
3038
3039</div>
3040
3041
3042<!-- _______________________________________________________________________ -->
3043<div class="doc_subsubsection">
3044 <a name="i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
3045</div>
3046
3047<div class="doc_text">
3048
3049<h5>Syntax:</h5>
3050
3051<pre>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3052 declare sbyte* %llvm.gcread(sbyte* %ObjPtr, sbyte** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3053</pre>
3054
3055<h5>Overview:</h5>
3056
3057<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
3058locations, allowing garbage collector implementations that require read
3059barriers.</p>
3060
3061<h5>Arguments:</h5>
3062
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3063<p>The second argument is the address to read from, which should be an address
3064allocated from the garbage collector. The first object is a pointer to the
3065start of the referenced object, if needed by the language runtime (otherwise
3066null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3067
3068<h5>Semantics:</h5>
3069
3070<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
3071instruction, but may be replaced with substantially more complex code by the
3072garbage collector runtime, as needed.</p>
3073
3074</div>
3075
3076
3077<!-- _______________________________________________________________________ -->
3078<div class="doc_subsubsection">
3079 <a name="i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
3080</div>
3081
3082<div class="doc_text">
3083
3084<h5>Syntax:</h5>
3085
3086<pre>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3087 declare void %llvm.gcwrite(sbyte* %P1, sbyte* %Obj, sbyte** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3088</pre>
3089
3090<h5>Overview:</h5>
3091
3092<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
3093locations, allowing garbage collector implementations that require write
3094barriers (such as generational or reference counting collectors).</p>
3095
3096<h5>Arguments:</h5>
3097
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3098<p>The first argument is the reference to store, the second is the start of the
3099object to store it to, and the third is the address of the field of Obj to
3100store to. If the runtime does not require a pointer to the object, Obj may be
3101null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3102
3103<h5>Semantics:</h5>
3104
3105<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
3106instruction, but may be replaced with substantially more complex code by the
3107garbage collector runtime, as needed.</p>
3108
3109</div>
3110
3111
3112
3113<!-- ======================================================================= -->
3114<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3115 <a name="int_codegen">Code Generator Intrinsics</a>
3116</div>
3117
3118<div class="doc_text">
3119<p>
3120These intrinsics are provided by LLVM to expose special features that may only
3121be implemented with code generator support.
3122</p>
3123
3124</div>
3125
3126<!-- _______________________________________________________________________ -->
3127<div class="doc_subsubsection">
3128 <a name="i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
3129</div>
3130
3131<div class="doc_text">
3132
3133<h5>Syntax:</h5>
3134<pre>
Chris Lattnerfcf39d42006-01-13 01:20:27 +0000[diff] [blame]3135 declare sbyte *%llvm.returnaddress(uint &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3136</pre>
3137
3138<h5>Overview:</h5>
3139
3140<p>
3141The '<tt>llvm.returnaddress</tt>' intrinsic returns a target-specific value
3142indicating the return address of the current function or one of its callers.
3143</p>
3144
3145<h5>Arguments:</h5>
3146
3147<p>
3148The argument to this intrinsic indicates which function to return the address
3149for. Zero indicates the calling function, one indicates its caller, etc. The
3150argument is <b>required</b> to be a constant integer value.
3151</p>
3152
3153<h5>Semantics:</h5>
3154
3155<p>
3156The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
3157the return address of the specified call frame, or zero if it cannot be
3158identified. The value returned by this intrinsic is likely to be incorrect or 0
3159for arguments other than zero, so it should only be used for debugging purposes.
3160</p>
3161
3162<p>
3163Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]3164aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3165source-language caller.
3166</p>
3167</div>
3168
3169
3170<!-- _______________________________________________________________________ -->
3171<div class="doc_subsubsection">
3172 <a name="i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
3173</div>
3174
3175<div class="doc_text">
3176
3177<h5>Syntax:</h5>
3178<pre>
Chris Lattnerfcf39d42006-01-13 01:20:27 +0000[diff] [blame]3179 declare sbyte *%llvm.frameaddress(uint &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3180</pre>
3181
3182<h5>Overview:</h5>
3183
3184<p>
3185The '<tt>llvm.frameaddress</tt>' intrinsic returns the target-specific frame
3186pointer value for the specified stack frame.
3187</p>
3188
3189<h5>Arguments:</h5>
3190
3191<p>
3192The argument to this intrinsic indicates which function to return the frame
3193pointer for. Zero indicates the calling function, one indicates its caller,
3194etc. The argument is <b>required</b> to be a constant integer value.
3195</p>
3196
3197<h5>Semantics:</h5>
3198
3199<p>
3200The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
3201the frame address of the specified call frame, or zero if it cannot be
3202identified. The value returned by this intrinsic is likely to be incorrect or 0
3203for arguments other than zero, so it should only be used for debugging purposes.
3204</p>
3205
3206<p>
3207Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]3208aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3209source-language caller.
3210</p>
3211</div>
3212
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3213<!-- _______________________________________________________________________ -->
3214<div class="doc_subsubsection">
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]3215 <a name="i_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
3216</div>
3217
3218<div class="doc_text">
3219
3220<h5>Syntax:</h5>
3221<pre>
3222 declare sbyte *%llvm.stacksave()
3223</pre>
3224
3225<h5>Overview:</h5>
3226
3227<p>
3228The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
3229the function stack, for use with <a href="#i_stackrestore">
3230<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
3231features like scoped automatic variable sized arrays in C99.
3232</p>
3233
3234<h5>Semantics:</h5>
3235
3236<p>
3237This intrinsic returns a opaque pointer value that can be passed to <a
3238href="#i_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
3239<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
3240<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
3241state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
3242practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
3243that were allocated after the <tt>llvm.stacksave</tt> was executed.
3244</p>
3245
3246</div>
3247
3248<!-- _______________________________________________________________________ -->
3249<div class="doc_subsubsection">
3250 <a name="i_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
3251</div>
3252
3253<div class="doc_text">
3254
3255<h5>Syntax:</h5>
3256<pre>
3257 declare void %llvm.stackrestore(sbyte* %ptr)
3258</pre>
3259
3260<h5>Overview:</h5>
3261
3262<p>
3263The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
3264the function stack to the state it was in when the corresponding <a
3265href="#llvm.stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
3266useful for implementing language features like scoped automatic variable sized
3267arrays in C99.
3268</p>
3269
3270<h5>Semantics:</h5>
3271
3272<p>
3273See the description for <a href="#i_stacksave"><tt>llvm.stacksave</tt></a>.
3274</p>
3275
3276</div>
3277
3278
3279<!-- _______________________________________________________________________ -->
3280<div class="doc_subsubsection">
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3281 <a name="i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
3282</div>
3283
3284<div class="doc_text">
3285
3286<h5>Syntax:</h5>
3287<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]3288 declare void %llvm.prefetch(sbyte * &lt;address&gt;,
3289 uint &lt;rw&gt;, uint &lt;locality&gt;)
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3290</pre>
3291
3292<h5>Overview:</h5>
3293
3294
3295<p>
3296The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3297a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
3298no
3299effect on the behavior of the program but can change its performance
Chris Lattner2a615362005-02-28 19:47:14 +0000[diff] [blame]3300characteristics.
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3301</p>
3302
3303<h5>Arguments:</h5>
3304
3305<p>
3306<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
3307determining if the fetch should be for a read (0) or write (1), and
3308<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattneraeffb4a2005-03-07 20:31:38 +0000[diff] [blame]3309locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3310<tt>locality</tt> arguments must be constant integers.
3311</p>
3312
3313<h5>Semantics:</h5>
3314
3315<p>
3316This intrinsic does not modify the behavior of the program. In particular,
3317prefetches cannot trap and do not produce a value. On targets that support this
3318intrinsic, the prefetch can provide hints to the processor cache for better
3319performance.
3320</p>
3321
3322</div>
3323
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]3324<!-- _______________________________________________________________________ -->
3325<div class="doc_subsubsection">
3326 <a name="i_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
3327</div>
3328
3329<div class="doc_text">
3330
3331<h5>Syntax:</h5>
3332<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]3333 declare void %llvm.pcmarker( uint &lt;id&gt; )
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]3334</pre>
3335
3336<h5>Overview:</h5>
3337
3338
3339<p>
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3340The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
3341(PC) in a region of
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]3342code to simulators and other tools. The method is target specific, but it is
3343expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]3344The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnerd07c3f42005-11-15 06:07:55 +0000[diff] [blame]3345after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb3e7afd2006-03-24 07:16:10 +0000[diff] [blame]3346optimizations. The intended use is to be inserted after optimizations to allow
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3347correlations of simulation runs.
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]3348</p>
3349
3350<h5>Arguments:</h5>
3351
3352<p>
3353<tt>id</tt> is a numerical id identifying the marker.
3354</p>
3355
3356<h5>Semantics:</h5>
3357
3358<p>
3359This intrinsic does not modify the behavior of the program. Backends that do not
3360support this intrinisic may ignore it.
3361</p>
3362
3363</div>
3364
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]3365<!-- _______________________________________________________________________ -->
3366<div class="doc_subsubsection">
3367 <a name="i_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
3368</div>
3369
3370<div class="doc_text">
3371
3372<h5>Syntax:</h5>
3373<pre>
3374 declare ulong %llvm.readcyclecounter( )
3375</pre>
3376
3377<h5>Overview:</h5>
3378
3379
3380<p>
3381The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
3382counter register (or similar low latency, high accuracy clocks) on those targets
3383that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
3384As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
3385should only be used for small timings.
3386</p>
3387
3388<h5>Semantics:</h5>
3389
3390<p>
3391When directly supported, reading the cycle counter should not modify any memory.
3392Implementations are allowed to either return a application specific value or a
3393system wide value. On backends without support, this is lowered to a constant 0.
3394</p>
3395
3396</div>
3397
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3398<!-- ======================================================================= -->
3399<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3400 <a name="int_libc">Standard C Library Intrinsics</a>
3401</div>
3402
3403<div class="doc_text">
3404<p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3405LLVM provides intrinsics for a few important standard C library functions.
3406These intrinsics allow source-language front-ends to pass information about the
3407alignment of the pointer arguments to the code generator, providing opportunity
3408for more efficient code generation.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3409</p>
3410
3411</div>
3412
3413<!-- _______________________________________________________________________ -->
3414<div class="doc_subsubsection">
3415 <a name="i_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
3416</div>
3417
3418<div class="doc_text">
3419
3420<h5>Syntax:</h5>
3421<pre>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3422 declare void %llvm.memcpy.i32(sbyte* &lt;dest&gt;, sbyte* &lt;src&gt;,
3423 uint &lt;len&gt;, uint &lt;align&gt;)
3424 declare void %llvm.memcpy.i64(sbyte* &lt;dest&gt;, sbyte* &lt;src&gt;,
3425 ulong &lt;len&gt;, uint &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3426</pre>
3427
3428<h5>Overview:</h5>
3429
3430<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3431The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3432location to the destination location.
3433</p>
3434
3435<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3436Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
3437intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3438</p>
3439
3440<h5>Arguments:</h5>
3441
3442<p>
3443The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3444the source. The third argument is an integer argument
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3445specifying the number of bytes to copy, and the fourth argument is the alignment
3446of the source and destination locations.
3447</p>
3448
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]3449<p>
3450If 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]3451the caller guarantees that both the source and destination pointers are aligned
3452to that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]3453</p>
3454
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3455<h5>Semantics:</h5>
3456
3457<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3458The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3459location to the destination location, which are not allowed to overlap. It
3460copies "len" bytes of memory over. If the argument is known to be aligned to
3461some boundary, this can be specified as the fourth argument, otherwise it should
3462be set to 0 or 1.
3463</p>
3464</div>
3465
3466
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]3467<!-- _______________________________________________________________________ -->
3468<div class="doc_subsubsection">
3469 <a name="i_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
3470</div>
3471
3472<div class="doc_text">
3473
3474<h5>Syntax:</h5>
3475<pre>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3476 declare void %llvm.memmove.i32(sbyte* &lt;dest&gt;, sbyte* &lt;src&gt;,
3477 uint &lt;len&gt;, uint &lt;align&gt;)
3478 declare void %llvm.memmove.i64(sbyte* &lt;dest&gt;, sbyte* &lt;src&gt;,
3479 ulong &lt;len&gt;, uint &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]3480</pre>
3481
3482<h5>Overview:</h5>
3483
3484<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3485The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
3486location to the destination location. It is similar to the
3487'<tt>llvm.memcmp</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]3488</p>
3489
3490<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3491Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
3492intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]3493</p>
3494
3495<h5>Arguments:</h5>
3496
3497<p>
3498The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3499the source. The third argument is an integer argument
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]3500specifying the number of bytes to copy, and the fourth argument is the alignment
3501of the source and destination locations.
3502</p>
3503
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]3504<p>
3505If 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]3506the caller guarantees that the source and destination pointers are aligned to
3507that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]3508</p>
3509
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]3510<h5>Semantics:</h5>
3511
3512<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3513The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]3514location to the destination location, which may overlap. It
3515copies "len" bytes of memory over. If the argument is known to be aligned to
3516some boundary, this can be specified as the fourth argument, otherwise it should
3517be set to 0 or 1.
3518</p>
3519</div>
3520
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3521
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3522<!-- _______________________________________________________________________ -->
3523<div class="doc_subsubsection">
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3524 <a name="i_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3525</div>
3526
3527<div class="doc_text">
3528
3529<h5>Syntax:</h5>
3530<pre>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3531 declare void %llvm.memset.i32(sbyte* &lt;dest&gt;, ubyte &lt;val&gt;,
3532 uint &lt;len&gt;, uint &lt;align&gt;)
3533 declare void %llvm.memset.i64(sbyte* &lt;dest&gt;, ubyte &lt;val&gt;,
3534 ulong &lt;len&gt;, uint &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3535</pre>
3536
3537<h5>Overview:</h5>
3538
3539<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3540The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3541byte value.
3542</p>
3543
3544<p>
3545Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
3546does not return a value, and takes an extra alignment argument.
3547</p>
3548
3549<h5>Arguments:</h5>
3550
3551<p>
3552The first argument is a pointer to the destination to fill, the second is the
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3553byte value to fill it with, the third argument is an integer
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3554argument specifying the number of bytes to fill, and the fourth argument is the
3555known alignment of destination location.
3556</p>
3557
3558<p>
3559If 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]3560the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3561</p>
3562
3563<h5>Semantics:</h5>
3564
3565<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3566The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
3567the
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3568destination location. If the argument is known to be aligned to some boundary,
3569this can be specified as the fourth argument, otherwise it should be set to 0 or
35701.
3571</p>
3572</div>
3573
3574
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]3575<!-- _______________________________________________________________________ -->
3576<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]3577 <a name="i_isunordered">'<tt>llvm.isunordered.*</tt>' Intrinsic</a>
Alkis Evlogimenos26bbe932004-06-13 01:16:15 +0000[diff] [blame]3578</div>
3579
3580<div class="doc_text">
3581
3582<h5>Syntax:</h5>
3583<pre>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]3584 declare bool %llvm.isunordered.f32(float Val1, float Val2)
3585 declare bool %llvm.isunordered.f64(double Val1, double Val2)
Alkis Evlogimenos26bbe932004-06-13 01:16:15 +0000[diff] [blame]3586</pre>
3587
3588<h5>Overview:</h5>
3589
3590<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]3591The '<tt>llvm.isunordered</tt>' intrinsics return true if either or both of the
Alkis Evlogimenos26bbe932004-06-13 01:16:15 +0000[diff] [blame]3592specified floating point values is a NAN.
3593</p>
3594
3595<h5>Arguments:</h5>
3596
3597<p>
3598The arguments are floating point numbers of the same type.
3599</p>
3600
3601<h5>Semantics:</h5>
3602
3603<p>
3604If either or both of the arguments is a SNAN or QNAN, it returns true, otherwise
3605false.
3606</p>
3607</div>
3608
3609
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]3610<!-- _______________________________________________________________________ -->
3611<div class="doc_subsubsection">
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3612 <a name="i_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]3613</div>
3614
3615<div class="doc_text">
3616
3617<h5>Syntax:</h5>
3618<pre>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]3619 declare double %llvm.sqrt.f32(float Val)
3620 declare double %llvm.sqrt.f64(double Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]3621</pre>
3622
3623<h5>Overview:</h5>
3624
3625<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]3626The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]3627returning the same value as the libm '<tt>sqrt</tt>' function would. Unlike
3628<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
3629negative numbers (which allows for better optimization).
3630</p>
3631
3632<h5>Arguments:</h5>
3633
3634<p>
3635The argument and return value are floating point numbers of the same type.
3636</p>
3637
3638<h5>Semantics:</h5>
3639
3640<p>
3641This function returns the sqrt of the specified operand if it is a positive
3642floating point number.
3643</p>
3644</div>
3645
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3646<!-- ======================================================================= -->
3647<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]3648 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3649</div>
3650
3651<div class="doc_text">
3652<p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]3653LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3654These allow efficient code generation for some algorithms.
3655</p>
3656
3657</div>
3658
3659<!-- _______________________________________________________________________ -->
3660<div class="doc_subsubsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]3661 <a name="i_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
3662</div>
3663
3664<div class="doc_text">
3665
3666<h5>Syntax:</h5>
3667<pre>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3668 declare ushort %llvm.bswap.i16(ushort &lt;id&gt;)
3669 declare uint %llvm.bswap.i32(uint &lt;id&gt;)
3670 declare ulong %llvm.bswap.i64(ulong &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]3671</pre>
3672
3673<h5>Overview:</h5>
3674
3675<p>
3676The '<tt>llvm.bwsap</tt>' family of intrinsics is used to byteswap a 16, 32 or
367764 bit quantity. These are useful for performing operations on data that is not
3678in the target's native byte order.
3679</p>
3680
3681<h5>Semantics:</h5>
3682
3683<p>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3684The <tt>llvm.bswap.16</tt> intrinsic returns a ushort value that has the high and low
3685byte of the input ushort swapped. Similarly, the <tt>llvm.bswap.i32</tt> intrinsic
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]3686returns a uint value that has the four bytes of the input uint swapped, so that
3687if 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]3688bytes 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]3689to 64 bits.
3690</p>
3691
3692</div>
3693
3694<!-- _______________________________________________________________________ -->
3695<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]3696 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3697</div>
3698
3699<div class="doc_text">
3700
3701<h5>Syntax:</h5>
3702<pre>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3703 declare ubyte %llvm.ctpop.i8 (ubyte &lt;src&gt;)
3704 declare ushort %llvm.ctpop.i16(ushort &lt;src&gt;)
3705 declare uint %llvm.ctpop.i32(uint &lt;src&gt;)
3706 declare ulong %llvm.ctpop.i64(ulong &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3707</pre>
3708
3709<h5>Overview:</h5>
3710
3711<p>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3712The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
3713value.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3714</p>
3715
3716<h5>Arguments:</h5>
3717
3718<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]3719The only argument is the value to be counted. The argument may be of any
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3720unsigned integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3721</p>
3722
3723<h5>Semantics:</h5>
3724
3725<p>
3726The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
3727</p>
3728</div>
3729
3730<!-- _______________________________________________________________________ -->
3731<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]3732 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3733</div>
3734
3735<div class="doc_text">
3736
3737<h5>Syntax:</h5>
3738<pre>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3739 declare ubyte %llvm.ctlz.i8 (ubyte &lt;src&gt;)
3740 declare ushort %llvm.ctlz.i16(ushort &lt;src&gt;)
3741 declare uint %llvm.ctlz.i32(uint &lt;src&gt;)
3742 declare ulong %llvm.ctlz.i64(ulong &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3743</pre>
3744
3745<h5>Overview:</h5>
3746
3747<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]3748The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
3749leading zeros in a variable.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3750</p>
3751
3752<h5>Arguments:</h5>
3753
3754<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]3755The only argument is the value to be counted. The argument may be of any
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3756unsigned integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3757</p>
3758
3759<h5>Semantics:</h5>
3760
3761<p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]3762The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
3763in 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]3764of src. For example, <tt>llvm.ctlz(int 2) = 30</tt>.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3765</p>
3766</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]3767
3768
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]3769
3770<!-- _______________________________________________________________________ -->
3771<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]3772 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]3773</div>
3774
3775<div class="doc_text">
3776
3777<h5>Syntax:</h5>
3778<pre>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3779 declare ubyte %llvm.cttz.i8 (ubyte &lt;src&gt;)
3780 declare ushort %llvm.cttz.i16(ushort &lt;src&gt;)
3781 declare uint %llvm.cttz.i32(uint &lt;src&gt;)
3782 declare ulong %llvm.cttz.i64(ulong &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]3783</pre>
3784
3785<h5>Overview:</h5>
3786
3787<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]3788The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
3789trailing zeros.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]3790</p>
3791
3792<h5>Arguments:</h5>
3793
3794<p>
3795The only argument is the value to be counted. The argument may be of any
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3796unsigned integer type. The return type must match the argument type.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]3797</p>
3798
3799<h5>Semantics:</h5>
3800
3801<p>
3802The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
3803in a variable. If the src == 0 then the result is the size in bits of the type
3804of src. For example, <tt>llvm.cttz(2) = 1</tt>.
3805</p>
3806</div>
3807
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3808<!-- ======================================================================= -->
3809<div class="doc_subsection">
3810 <a name="int_debugger">Debugger Intrinsics</a>
3811</div>
3812
3813<div class="doc_text">
3814<p>
3815The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
3816are described in the <a
3817href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
3818Debugging</a> document.
3819</p>
3820</div>
3821
3822
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3823<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3824<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]3825<address>
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3830
3831 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]3832 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]3833 Last modified: $Date$
3834</address>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3835</body>
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