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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 92f8230f012797461ee2a07a1cacf2eb8aa9ba55 / . / docs / LangRef.html
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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>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]27 <li><a href="#paramattrs">Parameter Attributes</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]28 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]29 </ol>
30 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]31 <li><a href="#typesystem">Type System</a>
32 <ol>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]33 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]34 <ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]35 <li><a href="#t_classifications">Type Classifications</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]36 </ol>
37 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]38 <li><a href="#t_derived">Derived Types</a>
39 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]40 <li><a href="#t_array">Array Type</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]41 <li><a href="#t_function">Function Type</a></li>
42 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]43 <li><a href="#t_struct">Structure Type</a></li>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]44 <li><a href="#t_pstruct">Packed Structure Type</a></li>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]45 <li><a href="#t_packed">Packed Type</a></li>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]46 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]47 </ol>
48 </li>
49 </ol>
50 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]51 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]52 <ol>
53 <li><a href="#simpleconstants">Simple Constants</a>
54 <li><a href="#aggregateconstants">Aggregate Constants</a>
55 <li><a href="#globalconstants">Global Variable and Function Addresses</a>
56 <li><a href="#undefvalues">Undefined Values</a>
57 <li><a href="#constantexprs">Constant Expressions</a>
58 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]59 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]60 <li><a href="#othervalues">Other Values</a>
61 <ol>
62 <li><a href="#inlineasm">Inline Assembler Expressions</a>
63 </ol>
64 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]65 <li><a href="#instref">Instruction Reference</a>
66 <ol>
67 <li><a href="#terminators">Terminator Instructions</a>
68 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]69 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
70 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]71 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
72 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]73 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]74 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]75 </ol>
76 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]77 <li><a href="#binaryops">Binary Operations</a>
78 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]79 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
80 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
81 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]82 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
83 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
84 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]85 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
86 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
87 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]88 </ol>
89 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]90 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
91 <ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]92 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]93 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]94 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
95 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]96 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
97 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]98 </ol>
99 </li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]100 <li><a href="#vectorops">Vector Operations</a>
101 <ol>
102 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
103 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
104 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]105 </ol>
106 </li>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]107 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]108 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]109 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
110 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
111 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]112 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
113 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
114 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]115 </ol>
116 </li>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]117 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]118 <ol>
119 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
120 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
121 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
122 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
123 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]124 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
125 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
126 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
127 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]128 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
129 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]130 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]131 </ol>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]132 <li><a href="#otherops">Other Operations</a>
133 <ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]134 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
135 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]136 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]137 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]138 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]139 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]140 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]141 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]142 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]143 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]144 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]145 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]146 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
147 <ol>
148 <li><a href="#i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
149 <li><a href="#i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
150 <li><a href="#i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
151 </ol>
152 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]153 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
154 <ol>
155 <li><a href="#i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
156 <li><a href="#i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
157 <li><a href="#i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
158 </ol>
159 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]160 <li><a href="#int_codegen">Code Generator Intrinsics</a>
161 <ol>
162 <li><a href="#i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
163 <li><a href="#i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]164 <li><a href="#i_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
165 <li><a href="#i_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]166 <li><a href="#i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]167 <li><a href="#i_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]168 <li><a href="#i_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]169 </ol>
170 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]171 <li><a href="#int_libc">Standard C Library Intrinsics</a>
172 <ol>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]173 <li><a href="#i_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
174 <li><a href="#i_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
175 <li><a href="#i_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]176 <li><a href="#i_isunordered">'<tt>llvm.isunordered.*</tt>' Intrinsic</a></li>
177 <li><a href="#i_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]178 <li><a href="#i_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]179 </ol>
180 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]181 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]182 <ol>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]183 <li><a href="#i_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]184 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
185 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
186 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]187 </ol>
188 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]189 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]190 </ol>
191 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]192</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]193
194<div class="doc_author">
195 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
196 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]197</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]198
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]199<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]200<div class="doc_section"> <a name="abstract">Abstract </a></div>
201<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]202
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]203<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]204<p>This document is a reference manual for the LLVM assembly language.
205LLVM is an SSA based representation that provides type safety,
206low-level operations, flexibility, and the capability of representing
207'all' high-level languages cleanly. It is the common code
208representation used throughout all phases of the LLVM compilation
209strategy.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]210</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]211
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]212<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]213<div class="doc_section"> <a name="introduction">Introduction</a> </div>
214<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]215
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]216<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]217
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]218<p>The LLVM code representation is designed to be used in three
219different forms: as an in-memory compiler IR, as an on-disk bytecode
220representation (suitable for fast loading by a Just-In-Time compiler),
221and as a human readable assembly language representation. This allows
222LLVM to provide a powerful intermediate representation for efficient
223compiler transformations and analysis, while providing a natural means
224to debug and visualize the transformations. The three different forms
225of LLVM are all equivalent. This document describes the human readable
226representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]227
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]228<p>The LLVM representation aims to be light-weight and low-level
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]229while being expressive, typed, and extensible at the same time. It
230aims to be a "universal IR" of sorts, by being at a low enough level
231that high-level ideas may be cleanly mapped to it (similar to how
232microprocessors are "universal IR's", allowing many source languages to
233be mapped to them). By providing type information, LLVM can be used as
234the target of optimizations: for example, through pointer analysis, it
235can be proven that a C automatic variable is never accessed outside of
236the current function... allowing it to be promoted to a simple SSA
237value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]238
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]239</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]240
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]241<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]242<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]243
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]244<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]245
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]246<p>It is important to note that this document describes 'well formed'
247LLVM assembly language. There is a difference between what the parser
248accepts and what is considered 'well formed'. For example, the
249following instruction is syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]250
251<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]252 %x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]253</pre>
254
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]255<p>...because the definition of <tt>%x</tt> does not dominate all of
256its uses. The LLVM infrastructure provides a verification pass that may
257be used to verify that an LLVM module is well formed. This pass is
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]258automatically run by the parser after parsing input assembly and by
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]259the optimizer before it outputs bytecode. The violations pointed out
260by the verifier pass indicate bugs in transformation passes or input to
261the parser.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]262
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]263<!-- Describe the typesetting conventions here. --> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]264
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]265<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]266<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]267<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]268
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]269<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]270
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]271<p>LLVM uses three different forms of identifiers, for different
272purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]273
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]274<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]275 <li>Named values are represented as a string of characters with a '%' prefix.
276 For example, %foo, %DivisionByZero, %a.really.long.identifier. The actual
277 regular expression used is '<tt>%[a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
278 Identifiers which require other characters in their names can be surrounded
279 with quotes. In this way, anything except a <tt>"</tt> character can be used
280 in a name.</li>
281
282 <li>Unnamed values are represented as an unsigned numeric value with a '%'
283 prefix. For example, %12, %2, %44.</li>
284
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]285 <li>Constants, which are described in a <a href="#constants">section about
286 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]287</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]288
289<p>LLVM requires that values start with a '%' sign for two reasons: Compilers
290don't need to worry about name clashes with reserved words, and the set of
291reserved words may be expanded in the future without penalty. Additionally,
292unnamed identifiers allow a compiler to quickly come up with a temporary
293variable without having to avoid symbol table conflicts.</p>
294
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]295<p>Reserved words in LLVM are very similar to reserved words in other
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]296languages. There are keywords for different opcodes
297('<tt><a href="#i_add">add</a></tt>',
298 '<tt><a href="#i_bitcast">bitcast</a></tt>',
299 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]300href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]301and others. These reserved words cannot conflict with variable names, because
302none of them start with a '%' character.</p>
303
304<p>Here is an example of LLVM code to multiply the integer variable
305'<tt>%X</tt>' by 8:</p>
306
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]307<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]308
309<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]310 %result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]311</pre>
312
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]313<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]314
315<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]316 %result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]317</pre>
318
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]319<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]320
321<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]322 <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
323 <a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
324 %result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]325</pre>
326
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]327<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
328important lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]329
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]330<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]331
332 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
333 line.</li>
334
335 <li>Unnamed temporaries are created when the result of a computation is not
336 assigned to a named value.</li>
337
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]338 <li>Unnamed temporaries are numbered sequentially</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]339
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]340</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]341
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]342<p>...and it also shows a convention that we follow in this document. When
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]343demonstrating instructions, we will follow an instruction with a comment that
344defines the type and name of value produced. Comments are shown in italic
345text.</p>
346
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]347</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]348
349<!-- *********************************************************************** -->
350<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
351<!-- *********************************************************************** -->
352
353<!-- ======================================================================= -->
354<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
355</div>
356
357<div class="doc_text">
358
359<p>LLVM programs are composed of "Module"s, each of which is a
360translation unit of the input programs. Each module consists of
361functions, global variables, and symbol table entries. Modules may be
362combined together with the LLVM linker, which merges function (and
363global variable) definitions, resolves forward declarations, and merges
364symbol table entries. Here is an example of the "hello world" module:</p>
365
366<pre><i>; Declare the string constant as a global constant...</i>
367<a href="#identifiers">%.LC0</a> = <a href="#linkage_internal">internal</a> <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]368 href="#globalvars">constant</a> <a href="#t_array">[13 x i8 ]</a> c"hello world\0A\00" <i>; [13 x i8 ]*</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]369
370<i>; External declaration of the puts function</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]371<a href="#functionstructure">declare</a> i32 %puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]372
Chris Lattner81c01f02006-06-13 03:05:47 +0000[diff] [blame]373<i>; Global variable / Function body section separator</i>
374implementation
375
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]376<i>; Definition of main function</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]377define i32 %main() { <i>; i32()* </i>
378 <i>; Convert [13x i8 ]* to i8 *...</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]379 %cast210 = <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]380 href="#i_getelementptr">getelementptr</a> [13 x i8 ]* %.LC0, i64 0, i64 0 <i>; i8 *</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]381
382 <i>; Call puts function to write out the string to stdout...</i>
383 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]384 href="#i_call">call</a> i32 %puts(i8 * %cast210) <i>; i32</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]385 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]386 href="#i_ret">ret</a> i32 0<br>}<br></pre>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]387
388<p>This example is made up of a <a href="#globalvars">global variable</a>
389named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
390function, and a <a href="#functionstructure">function definition</a>
391for "<tt>main</tt>".</p>
392
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]393<p>In general, a module is made up of a list of global values,
394where both functions and global variables are global values. Global values are
395represented by a pointer to a memory location (in this case, a pointer to an
396array of char, and a pointer to a function), and have one of the following <a
397href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]398
Chris Lattner81c01f02006-06-13 03:05:47 +0000[diff] [blame]399<p>Due to a limitation in the current LLVM assembly parser (it is limited by
400one-token lookahead), modules are split into two pieces by the "implementation"
401keyword. Global variable prototypes and definitions must occur before the
402keyword, and function definitions must occur after it. Function prototypes may
403occur either before or after it. In the future, the implementation keyword may
404become a noop, if the parser gets smarter.</p>
405
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]406</div>
407
408<!-- ======================================================================= -->
409<div class="doc_subsection">
410 <a name="linkage">Linkage Types</a>
411</div>
412
413<div class="doc_text">
414
415<p>
416All Global Variables and Functions have one of the following types of linkage:
417</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]418
419<dl>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]420
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]421 <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]422
423 <dd>Global values with internal linkage are only directly accessible by
424 objects in the current module. In particular, linking code into a module with
425 an internal global value may cause the internal to be renamed as necessary to
426 avoid collisions. Because the symbol is internal to the module, all
427 references can be updated. This corresponds to the notion of the
428 '<tt>static</tt>' keyword in C, or the idea of "anonymous namespaces" in C++.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]429 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]430
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]431 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]432
433 <dd>"<tt>linkonce</tt>" linkage is similar to <tt>internal</tt> linkage, with
434 the twist that linking together two modules defining the same
435 <tt>linkonce</tt> globals will cause one of the globals to be discarded. This
436 is typically used to implement inline functions. Unreferenced
437 <tt>linkonce</tt> globals are allowed to be discarded.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]438 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]439
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]440 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]441
442 <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage,
443 except that unreferenced <tt>weak</tt> globals may not be discarded. This is
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]444 used to implement constructs in C such as "<tt>i32 X;</tt>" at global scope.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]445 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]446
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]447 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]448
449 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
450 pointer to array type. When two global variables with appending linkage are
451 linked together, the two global arrays are appended together. This is the
452 LLVM, typesafe, equivalent of having the system linker append together
453 "sections" with identical names when .o files are linked.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]454 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]455
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]456 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]457
458 <dd>If none of the above identifiers are used, the global is externally
459 visible, meaning that it participates in linkage and can be used to resolve
460 external symbol references.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]461 </dd>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]462
463 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
464
465 <dd>"<tt>extern_weak</tt>" TBD
466 </dd>
467
468 <p>
469 The next two types of linkage are targeted for Microsoft Windows platform
470 only. They are designed to support importing (exporting) symbols from (to)
471 DLLs.
472 </p>
473
474 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
475
476 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
477 or variable via a global pointer to a pointer that is set up by the DLL
478 exporting the symbol. On Microsoft Windows targets, the pointer name is
479 formed by combining <code>_imp__</code> and the function or variable name.
480 </dd>
481
482 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
483
484 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
485 pointer to a pointer in a DLL, so that it can be referenced with the
486 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
487 name is formed by combining <code>_imp__</code> and the function or variable
488 name.
489 </dd>
490
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]491</dl>
492
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]493<p><a name="linkage_external">For example, since the "<tt>.LC0</tt>"
494variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
495variable and was linked with this one, one of the two would be renamed,
496preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
497external (i.e., lacking any linkage declarations), they are accessible
498outside of the current module. It is illegal for a function <i>declaration</i>
499to have any linkage type other than "externally visible".</a></p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]500
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]501</div>
502
503<!-- ======================================================================= -->
504<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]505 <a name="callingconv">Calling Conventions</a>
506</div>
507
508<div class="doc_text">
509
510<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
511and <a href="#i_invoke">invokes</a> can all have an optional calling convention
512specified for the call. The calling convention of any pair of dynamic
513caller/callee must match, or the behavior of the program is undefined. The
514following calling conventions are supported by LLVM, and more may be added in
515the future:</p>
516
517<dl>
518 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
519
520 <dd>This calling convention (the default if no other calling convention is
521 specified) matches the target C calling conventions. This calling convention
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]522 supports varargs function calls and tolerates some mismatch in the declared
Reid Spencer6f85b9d2006-12-28 16:55:55 +0000[diff] [blame]523 prototype and implemented declaration of the function (as does normal C). For
524 integer arguments less than 32-bits, the value will be sign-extended to
525 32-bits before the call is made. If zero-extension is required, use the
526 <tt>cextcc</tt> calling convention.
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]527 </dd>
528
Reid Spencer6f85b9d2006-12-28 16:55:55 +0000[diff] [blame]529 <dt><b>"<tt>cextcc(bitmask)</tt>" - The C with explicit extend calling
530 convention </b>:</dt>
531 <dd>This calling convention is exactly like the C calling convention except
532 that it is parameterized to provide a <tt>bitmask</tt> that indicates how
533 integer arguments of less than 32-bits should be extended. A zero bit
534 indicates zero-extension while a 1-bit indicates sign-extension. The least
535 significant bit always corresponds to the return type of the function. The
536 bits in the <tt>bitmask</tt> are assigned to the integer parameters of the
537 function that are smaller than 32-bits. For example, a bitmask of value
538 5 (0b0101) indicates that the return value is to be sign extended, the first
539 small integer argument is to be zero extended and the second small integer
540 argument is to be sign extended.</dd>
541
542
Chris Lattner5710ce92006-05-19 21:15:36 +0000[diff] [blame]543 <dt><b>"<tt>csretcc</tt>" - The C struct return calling convention</b>:</dt>
544
545 <dd>This calling convention matches the target C calling conventions, except
546 that functions with this convention are required to take a pointer as their
547 first argument, and the return type of the function must be void. This is
548 used for C functions that return aggregates by-value. In this case, the
549 function has been transformed to take a pointer to the struct as the first
550 argument to the function. For targets where the ABI specifies specific
551 behavior for structure-return calls, the calling convention can be used to
552 distinguish between struct return functions and other functions that take a
553 pointer to a struct as the first argument.
554 </dd>
555
Reid Spencer6f85b9d2006-12-28 16:55:55 +0000[diff] [blame]556 <dt><b>"<tt>csretextcc(bitmask)</tt>" - The C struct return with explicit
557 extend calling convention</b>:</dt>
558 <dd>This calling convention is exactly like the <tt>csret</tt> calling
559 convention except that it is parameterized to provide a <tt>bitmask</tt>
560 that indicates how integer arguments of less than 32-bits should be extended.
561 A zero bit indicates zero-extension while a 1-bit indicates sign-extension.
562 </dd>
563
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]564 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
565
566 <dd>This calling convention attempts to make calls as fast as possible
567 (e.g. by passing things in registers). This calling convention allows the
568 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner8cdc5bc2005-05-06 23:08:23 +0000[diff] [blame]569 without having to conform to an externally specified ABI. Implementations of
570 this convention should allow arbitrary tail call optimization to be supported.
571 This calling convention does not support varargs and requires the prototype of
572 all callees to exactly match the prototype of the function definition.
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]573 </dd>
574
575 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
576
577 <dd>This calling convention attempts to make code in the caller as efficient
578 as possible under the assumption that the call is not commonly executed. As
579 such, these calls often preserve all registers so that the call does not break
580 any live ranges in the caller side. This calling convention does not support
581 varargs and requires the prototype of all callees to exactly match the
582 prototype of the function definition.
583 </dd>
584
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]585 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]586
587 <dd>Any calling convention may be specified by number, allowing
588 target-specific calling conventions to be used. Target specific calling
589 conventions start at 64.
590 </dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]591</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]592
593<p>More calling conventions can be added/defined on an as-needed basis, to
594support pascal conventions or any other well-known target-independent
595convention.</p>
596
597</div>
598
599<!-- ======================================================================= -->
600<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]601 <a name="globalvars">Global Variables</a>
602</div>
603
604<div class="doc_text">
605
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]606<p>Global variables define regions of memory allocated at compilation time
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]607instead of run-time. Global variables may optionally be initialized, may have
608an explicit section to be placed in, and may
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]609have an optional explicit alignment specified. A
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]610variable may be defined as a global "constant," which indicates that the
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]611contents of the variable will <b>never</b> be modified (enabling better
612optimization, allowing the global data to be placed in the read-only section of
613an executable, etc). Note that variables that need runtime initialization
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]614cannot be marked "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]615
616<p>
617LLVM explicitly allows <em>declarations</em> of global variables to be marked
618constant, even if the final definition of the global is not. This capability
619can be used to enable slightly better optimization of the program, but requires
620the language definition to guarantee that optimizations based on the
621'constantness' are valid for the translation units that do not include the
622definition.
623</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]624
625<p>As SSA values, global variables define pointer values that are in
626scope (i.e. they dominate) all basic blocks in the program. Global
627variables always define a pointer to their "content" type because they
628describe a region of memory, and all memory objects in LLVM are
629accessed through pointers.</p>
630
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]631<p>LLVM allows an explicit section to be specified for globals. If the target
632supports it, it will emit globals to the section specified.</p>
633
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]634<p>An explicit alignment may be specified for a global. If not present, or if
635the alignment is set to zero, the alignment of the global is set by the target
636to whatever it feels convenient. If an explicit alignment is specified, the
637global is forced to have at least that much alignment. All alignments must be
638a power of 2.</p>
639
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]640</div>
641
642
643<!-- ======================================================================= -->
644<div class="doc_subsection">
645 <a name="functionstructure">Functions</a>
646</div>
647
648<div class="doc_text">
649
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]650<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
651an optional <a href="#linkage">linkage type</a>, an optional
652<a href="#callingconv">calling convention</a>, a return type, an optional
653<a href="#paramattrs">parameter attribute</a> for the return type, a function
654name, a (possibly empty) argument list (each with optional
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame^]655<a href="#paramattrs">parameter attributes</a>), an optional section, an
656optional alignment, an opening curly brace, a list of basic blocks, and a
657closing curly brace. LLVM function declarations
658consist of the "<tt>declare</tt>" keyword, an optional <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]659 href="#callingconv">calling convention</a>, a return type, an optional
660<a href="#paramattrs">parameter attribute</a> for the return type, a function
661name, a possibly empty list of arguments, and an optional alignment.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]662
663<p>A function definition contains a list of basic blocks, forming the CFG for
664the function. Each basic block may optionally start with a label (giving the
665basic block a symbol table entry), contains a list of instructions, and ends
666with a <a href="#terminators">terminator</a> instruction (such as a branch or
667function return).</p>
668
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]669<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]670executed on entrance to the function, and it is not allowed to have predecessor
671basic blocks (i.e. there can not be any branches to the entry block of a
672function). Because the block can have no predecessors, it also cannot have any
673<a href="#i_phi">PHI nodes</a>.</p>
674
675<p>LLVM functions are identified by their name and type signature. Hence, two
676functions with the same name but different parameter lists or return values are
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]677considered different functions, and LLVM will resolve references to each
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]678appropriately.</p>
679
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]680<p>LLVM allows an explicit section to be specified for functions. If the target
681supports it, it will emit functions to the section specified.</p>
682
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]683<p>An explicit alignment may be specified for a function. If not present, or if
684the alignment is set to zero, the alignment of the function is set by the target
685to whatever it feels convenient. If an explicit alignment is specified, the
686function is forced to have at least that much alignment. All alignments must be
687a power of 2.</p>
688
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]689</div>
690
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]691<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]692<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
693<div class="doc_text">
694 <p>The return type and each parameter of a function type may have a set of
695 <i>parameter attributes</i> associated with them. Parameter attributes are
696 used to communicate additional information about the result or parameters of
697 a function. Parameter attributes are considered to be part of the function
698 type so two functions types that differ only by the parameter attributes
699 are different function types.</p>
700
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame^]701 <p>Parameter attributes consist of an at sign (@) followed by either a single
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]702 keyword or a comma separate list of keywords enclosed in parentheses. For
703 example:<pre>
704 %someFunc = i16 @zext (i8 @(sext) %someParam)
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame^]705 %someFunc = i16 @zext (i8 @zext %someParam)</pre>
706 Note that the two function types above are unique because the parameter
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]707 has a different attribute (@sext in the first one, @zext in the second).</p>
708
709 <p>Currently, only the following parameter attributes are defined:
710 <dl>
711 <dt><tt>@zext</tt></dt>
712 <dd>This indicates that the parameter should be zero extended just before
713 a call to this function.</dd>
714 <dt><tt>@sext</tt></dt>
715 <dd>This indicates that the parameter should be sign extended just before
716 a call to this function.</dd>
717 </dl></p>
718
719 <p>The current motivation for parameter attributes is to enable the sign and
720 zero extend information necessary for the C calling convention to be passed
721 from the front end to LLVM. The <tt>@zext</tt> and <tt>@sext</tt> attributes
722 are used by the code generator to perform the required extension. However,
723 parameter attributes are an orthogonal feature to calling conventions and
724 may be used for other purposes in the future.</p>
725</div>
726
727<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]728<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]729 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]730</div>
731
732<div class="doc_text">
733<p>
734Modules may contain "module-level inline asm" blocks, which corresponds to the
735GCC "file scope inline asm" blocks. These blocks are internally concatenated by
736LLVM and treated as a single unit, but may be separated in the .ll file if
737desired. The syntax is very simple:
738</p>
739
740<div class="doc_code"><pre>
Chris Lattner52599e12006-01-24 00:37:20 +0000[diff] [blame]741 module asm "inline asm code goes here"
742 module asm "more can go here"
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]743</pre></div>
744
745<p>The strings can contain any character by escaping non-printable characters.
746 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
747 for the number.
748</p>
749
750<p>
751 The inline asm code is simply printed to the machine code .s file when
752 assembly code is generated.
753</p>
754</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]755
756
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]757<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]758<div class="doc_section"> <a name="typesystem">Type System</a> </div>
759<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]760
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]761<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]762
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]763<p>The LLVM type system is one of the most important features of the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]764intermediate representation. Being typed enables a number of
765optimizations to be performed on the IR directly, without having to do
766extra analyses on the side before the transformation. A strong type
767system makes it easier to read the generated code and enables novel
768analyses and transformations that are not feasible to perform on normal
769three address code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]770
771</div>
772
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]773<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]774<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]775<div class="doc_text">
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]776<p>The primitive types are the fundamental building blocks of the LLVM
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]777system. The current set of primitive types is as follows:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]778
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]779<table class="layout">
780 <tr class="layout">
781 <td class="left">
782 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]783 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]784 <tr><th>Type</th><th>Description</th></tr>
785 <tr><td><tt>void</tt></td><td>No value</td></tr>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]786 <tr><td><tt>i8</tt></td><td>Signless 8-bit value</td></tr>
787 <tr><td><tt>i32</tt></td><td>Signless 32-bit value</td></tr>
Misha Brukmancfa87bc2005-04-22 18:02:52 +0000[diff] [blame]788 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]789 <tr><td><tt>label</tt></td><td>Branch destination</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]790 </tbody>
791 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]792 </td>
793 <td class="right">
794 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]795 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]796 <tr><th>Type</th><th>Description</th></tr>
797 <tr><td><tt>bool</tt></td><td>True or False value</td></tr>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]798 <tr><td><tt>i16</tt></td><td>Signless 16-bit value</td></tr>
799 <tr><td><tt>i64</tt></td><td>Signless 64-bit value</td></tr>
800 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]801 </tbody>
802 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]803 </td>
804 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]805</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]806</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]807
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]808<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]809<div class="doc_subsubsection"> <a name="t_classifications">Type
810Classifications</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]811<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]812<p>These different primitive types fall into a few useful
813classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]814
815<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]816 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]817 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]818 <tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]819 <td><a name="t_integer">integer</a></td>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]820 <td><tt>i8, i16, i32, i64</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]821 </tr>
822 <tr>
823 <td><a name="t_integral">integral</a></td>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]824 <td><tt>bool, i8, i16, i32, i64</tt>
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]825 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]826 </tr>
827 <tr>
828 <td><a name="t_floating">floating point</a></td>
829 <td><tt>float, double</tt></td>
830 </tr>
831 <tr>
832 <td><a name="t_firstclass">first class</a></td>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]833 <td><tt>bool, i8, i16, i32, i64, float, double, <br/>
834 <a href="#t_pointer">pointer</a>,<a href="#t_packed">packed</a></tt>
835 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]836 </tr>
837 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]838</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]839
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]840<p>The <a href="#t_firstclass">first class</a> types are perhaps the
841most important. Values of these types are the only ones which can be
842produced by instructions, passed as arguments, or used as operands to
843instructions. This means that all structures and arrays must be
844manipulated either by pointer or by component.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]845</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]846
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_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]849
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]850<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]851
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]852<p>The real power in LLVM comes from the derived types in the system.
853This is what allows a programmer to represent arrays, functions,
854pointers, and other useful types. Note that these derived types may be
855recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]856
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]857</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]858
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]859<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]860<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]861
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]862<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]863
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]864<h5>Overview:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]865
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]866<p>The array type is a very simple derived type that arranges elements
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]867sequentially in memory. The array type requires a size (number of
868elements) and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]869
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]870<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]871
872<pre>
873 [&lt;# elements&gt; x &lt;elementtype&gt;]
874</pre>
875
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]876<p>The number of elements is a constant integer value; elementtype may
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]877be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]878
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]879<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]880<table class="layout">
881 <tr class="layout">
882 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]883 <tt>[40 x i32 ]</tt><br/>
884 <tt>[41 x i32 ]</tt><br/>
885 <tt>[40 x i32]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]886 </td>
887 <td class="left">
888 Array of 40 integer values.<br/>
889 Array of 41 integer values.<br/>
890 Array of 40 unsigned integer values.<br/>
891 </td>
892 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]893</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]894<p>Here are some examples of multidimensional arrays:</p>
895<table class="layout">
896 <tr class="layout">
897 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]898 <tt>[3 x [4 x i32]]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]899 <tt>[12 x [10 x float]]</tt><br/>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]900 <tt>[2 x [3 x [4 x i32]]]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]901 </td>
902 <td class="left">
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]903 3x4 array of integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]904 12x10 array of single precision floating point values.<br/>
905 2x3x4 array of unsigned integer values.<br/>
906 </td>
907 </tr>
908</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]909
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]910<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
911length array. Normally, accesses past the end of an array are undefined in
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]912LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
913As a special case, however, zero length arrays are recognized to be variable
914length. This allows implementation of 'pascal style arrays' with the LLVM
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]915type "{ i32, [0 x float]}", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]916
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]917</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]918
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]919<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]920<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]921<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]922<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]923<p>The function type can be thought of as a function signature. It
924consists of a return type and a list of formal parameter types.
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]925Function types are usually used to build virtual function tables
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]926(which are structures of pointers to functions), for indirect function
927calls, and when defining a function.</p>
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]928<p>
929The return type of a function type cannot be an aggregate type.
930</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]931<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]932<pre> &lt;returntype&gt; (&lt;parameter list&gt;)<br></pre>
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]933<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]934specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]935which indicates that the function takes a variable number of arguments.
936Variable argument functions can access their arguments with the <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]937 href="#int_varargs">variable argument handling intrinsic</a> functions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]938<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]939<table class="layout">
940 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame^]941 <td class="left"><tt>i32 (i32)</tt></td>
942 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]943 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame^]944 </tr><tr class="layout">
945 <td class="left"><tt>float (i16 @sext, i32 *) *</tt></td>
946 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
947 an <tt>i16</tt> that should be sign extended and a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]948 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame^]949 <tt>float</tt>.
950 </td>
951 </tr><tr class="layout">
952 <td class="left"><tt>i32 (i8*, ...)</tt></td>
953 <td class="left">A vararg function that takes at least one
954 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (signed char in C),
955 which returns an integer. This is the signature for <tt>printf</tt> in
956 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]957 </td>
958 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]959</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]960
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]961</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]962<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]963<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]964<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]965<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]966<p>The structure type is used to represent a collection of data members
967together in memory. The packing of the field types is defined to match
968the ABI of the underlying processor. The elements of a structure may
969be any type that has a size.</p>
970<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
971and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
972field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
973instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]974<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]975<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]976<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]977<table class="layout">
978 <tr class="layout">
979 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]980 <tt>{ i32, i32, i32 }</tt><br/>
981 <tt>{ float, i32 (i32) * }</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]982 </td>
983 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]984 a triple of three <tt>i32</tt> values<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]985 A pair, where the first element is a <tt>float</tt> and the second element
986 is a <a href="#t_pointer">pointer</a> to a <a href="#t_function">function</a>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]987 that takes an <tt>i32</tt>, returning an <tt>i32</tt>.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]988 </td>
989 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]990</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]991</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]992
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]993<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]994<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
995</div>
996<div class="doc_text">
997<h5>Overview:</h5>
998<p>The packed structure type is used to represent a collection of data members
999together in memory. There is no padding between fields. Further, the alignment
1000of a packed structure is 1 byte. The elements of a packed structure may
1001be any type that has a size.</p>
1002<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1003and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1004field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1005instruction.</p>
1006<h5>Syntax:</h5>
1007<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1008<h5>Examples:</h5>
1009<table class="layout">
1010 <tr class="layout">
1011 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1012 <tt> &lt; { i32, i32, i32 } &gt; </tt><br/>
1013 <tt> &lt; { float, i32 (i32) * } &gt; </tt><br/>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1014 </td>
1015 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1016 a triple of three <tt>i32</tt> values<br/>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1017 A pair, where the first element is a <tt>float</tt> and the second element
1018 is a <a href="#t_pointer">pointer</a> to a <a href="#t_function">function</a>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1019 that takes an <tt>i32</tt>, returning an <tt>i32</tt>.<br/>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1020 </td>
1021 </tr>
1022</table>
1023</div>
1024
1025<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1026<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1027<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1028<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1029<p>As in many languages, the pointer type represents a pointer or
1030reference to another object, which must live in memory.</p>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1031<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1032<pre> &lt;type&gt; *<br></pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1033<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1034<table class="layout">
1035 <tr class="layout">
1036 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1037 <tt>[4x i32]*</tt><br/>
1038 <tt>i32 (i32 *) *</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1039 </td>
1040 <td class="left">
1041 A <a href="#t_pointer">pointer</a> to <a href="#t_array">array</a> of
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1042 four <tt>i32</tt> values<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1043 A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1044 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
1045 <tt>i32</tt>.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1046 </td>
1047 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1048</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1049</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1050
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1051<!-- _______________________________________________________________________ -->
1052<div class="doc_subsubsection"> <a name="t_packed">Packed Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1053<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1054
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1055<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1056
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1057<p>A packed type is a simple derived type that represents a vector
1058of elements. Packed types are used when multiple primitive data
1059are operated in parallel using a single instruction (SIMD).
1060A packed type requires a size (number of
Chris Lattnerb8d172f2005-11-10 01:44:22 +0000[diff] [blame]1061elements) and an underlying primitive data type. Vectors must have a power
1062of two length (1, 2, 4, 8, 16 ...). Packed types are
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1063considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1064
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1065<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1066
1067<pre>
1068 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1069</pre>
1070
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1071<p>The number of elements is a constant integer value; elementtype may
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1072be any integral or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1073
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1074<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1075
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1076<table class="layout">
1077 <tr class="layout">
1078 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1079 <tt>&lt;4 x i32&gt;</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1080 <tt>&lt;8 x float&gt;</tt><br/>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1081 <tt>&lt;2 x i32&gt;</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1082 </td>
1083 <td class="left">
1084 Packed vector of 4 integer values.<br/>
1085 Packed vector of 8 floating-point values.<br/>
1086 Packed vector of 2 unsigned integer values.<br/>
1087 </td>
1088 </tr>
1089</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1090</div>
1091
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1092<!-- _______________________________________________________________________ -->
1093<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1094<div class="doc_text">
1095
1096<h5>Overview:</h5>
1097
1098<p>Opaque types are used to represent unknown types in the system. This
1099corresponds (for example) to the C notion of a foward declared structure type.
1100In LLVM, opaque types can eventually be resolved to any type (not just a
1101structure type).</p>
1102
1103<h5>Syntax:</h5>
1104
1105<pre>
1106 opaque
1107</pre>
1108
1109<h5>Examples:</h5>
1110
1111<table class="layout">
1112 <tr class="layout">
1113 <td class="left">
1114 <tt>opaque</tt>
1115 </td>
1116 <td class="left">
1117 An opaque type.<br/>
1118 </td>
1119 </tr>
1120</table>
1121</div>
1122
1123
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1124<!-- *********************************************************************** -->
1125<div class="doc_section"> <a name="constants">Constants</a> </div>
1126<!-- *********************************************************************** -->
1127
1128<div class="doc_text">
1129
1130<p>LLVM has several different basic types of constants. This section describes
1131them all and their syntax.</p>
1132
1133</div>
1134
1135<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1136<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1137
1138<div class="doc_text">
1139
1140<dl>
1141 <dt><b>Boolean constants</b></dt>
1142
1143 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
1144 constants of the <tt><a href="#t_primitive">bool</a></tt> type.
1145 </dd>
1146
1147 <dt><b>Integer constants</b></dt>
1148
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1149 <dd>Standard integers (such as '4') are constants of the <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1150 href="#t_integer">integer</a> type. Negative numbers may be used with signed
1151 integer types.
1152 </dd>
1153
1154 <dt><b>Floating point constants</b></dt>
1155
1156 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1157 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1158 notation (see below). Floating point constants must have a <a
1159 href="#t_floating">floating point</a> type. </dd>
1160
1161 <dt><b>Null pointer constants</b></dt>
1162
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1163 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1164 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1165
1166</dl>
1167
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1168<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1169of floating point constants. For example, the form '<tt>double
11700x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
11714.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1172(and the only time that they are generated by the disassembler) is when a
1173floating point constant must be emitted but it cannot be represented as a
1174decimal floating point number. For example, NaN's, infinities, and other
1175special values are represented in their IEEE hexadecimal format so that
1176assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1177
1178</div>
1179
1180<!-- ======================================================================= -->
1181<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1182</div>
1183
1184<div class="doc_text">
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1185<p>Aggregate constants arise from aggregation of simple constants
1186and smaller aggregate constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1187
1188<dl>
1189 <dt><b>Structure constants</b></dt>
1190
1191 <dd>Structure constants are represented with notation similar to structure
1192 type definitions (a comma separated list of elements, surrounded by braces
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1193 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* %G }</tt>",
1194 where "<tt>%G</tt>" is declared as "<tt>%G = external global i32</tt>". Structure constants
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1195 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1196 types of elements must match those specified by the type.
1197 </dd>
1198
1199 <dt><b>Array constants</b></dt>
1200
1201 <dd>Array constants are represented with notation similar to array type
1202 definitions (a comma separated list of elements, surrounded by square brackets
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1203 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1204 constants must have <a href="#t_array">array type</a>, and the number and
1205 types of elements must match those specified by the type.
1206 </dd>
1207
1208 <dt><b>Packed constants</b></dt>
1209
1210 <dd>Packed constants are represented with notation similar to packed type
1211 definitions (a comma separated list of elements, surrounded by
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1212 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32 42,
1213 i32 11, i32 74, i32 100 &gt;</tt>". Packed constants must have <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1214 href="#t_packed">packed type</a>, and the number and types of elements must
1215 match those specified by the type.
1216 </dd>
1217
1218 <dt><b>Zero initialization</b></dt>
1219
1220 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1221 value to zero of <em>any</em> type, including scalar and aggregate types.
1222 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]1223 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1224 initializers.
1225 </dd>
1226</dl>
1227
1228</div>
1229
1230<!-- ======================================================================= -->
1231<div class="doc_subsection">
1232 <a name="globalconstants">Global Variable and Function Addresses</a>
1233</div>
1234
1235<div class="doc_text">
1236
1237<p>The addresses of <a href="#globalvars">global variables</a> and <a
1238href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1239constants. These constants are explicitly referenced when the <a
1240href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1241href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1242file:</p>
1243
1244<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1245 %X = global i32 17
1246 %Y = global i32 42
1247 %Z = global [2 x i32*] [ i32* %X, i32* %Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1248</pre>
1249
1250</div>
1251
1252<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1253<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1254<div class="doc_text">
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1255 <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]1256 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1257 a constant is permitted.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1258
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1259 <p>Undefined values indicate to the compiler that the program is well defined
1260 no matter what value is used, giving the compiler more freedom to optimize.
1261 </p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1262</div>
1263
1264<!-- ======================================================================= -->
1265<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1266</div>
1267
1268<div class="doc_text">
1269
1270<p>Constant expressions are used to allow expressions involving other constants
1271to be used as constants. Constant expressions may be of any <a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1272href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1273that does not have side effects (e.g. load and call are not supported). The
1274following is the syntax for constant expressions:</p>
1275
1276<dl>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1277 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1278 <dd>Truncate a constant to another type. The bit size of CST must be larger
1279 than the bit size of TYPE. Both types must be integral.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1280
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1281 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1282 <dd>Zero extend a constant to another type. The bit size of CST must be
1283 smaller or equal to the bit size of TYPE. Both types must be integral.</dd>
1284
1285 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1286 <dd>Sign extend a constant to another type. The bit size of CST must be
1287 smaller or equal to the bit size of TYPE. Both types must be integral.</dd>
1288
1289 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1290 <dd>Truncate a floating point constant to another floating point type. The
1291 size of CST must be larger than the size of TYPE. Both types must be
1292 floating point.</dd>
1293
1294 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1295 <dd>Floating point extend a constant to another type. The size of CST must be
1296 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1297
1298 <dt><b><tt>fp2uint ( CST to TYPE )</tt></b></dt>
1299 <dd>Convert a floating point constant to the corresponding unsigned integer
1300 constant. TYPE must be an integer type. CST must be floating point. If the
1301 value won't fit in the integer type, the results are undefined.</dd>
1302
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1303 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1304 <dd>Convert a floating point constant to the corresponding signed integer
1305 constant. TYPE must be an integer type. CST must be floating point. If the
1306 value won't fit in the integer type, the results are undefined.</dd>
1307
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1308 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1309 <dd>Convert an unsigned integer constant to the corresponding floating point
1310 constant. TYPE must be floating point. CST must be of integer type. If the
1311 value won't fit in the floating point type, the results are undefined.</dd>
1312
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1313 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1314 <dd>Convert a signed integer constant to the corresponding floating point
1315 constant. TYPE must be floating point. CST must be of integer type. If the
1316 value won't fit in the floating point type, the results are undefined.</dd>
1317
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]1318 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1319 <dd>Convert a pointer typed constant to the corresponding integer constant
1320 TYPE must be an integer type. CST must be of pointer type. The CST value is
1321 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1322
1323 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1324 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1325 pointer type. CST must be of integer type. The CST value is zero extended,
1326 truncated, or unchanged to make it fit in a pointer size. This one is
1327 <i>really</i> dangerous!</dd>
1328
1329 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1330 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1331 identical (same number of bits). The conversion is done as if the CST value
1332 was stored to memory and read back as TYPE. In other words, no bits change
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]1333 with this operator, just the type. This can be used for conversion of
1334 packed types to any other type, as long as they have the same bit width. For
1335 pointers it is only valid to cast to another pointer type.
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1336 </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1337
1338 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1339
1340 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1341 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1342 instruction, the index list may have zero or more indexes, which are required
1343 to make sense for the type of "CSTPTR".</dd>
1344
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1345 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1346
1347 <dd>Perform the <a href="#i_select">select operation</a> on
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1348 constants.</dd>
1349
1350 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1351 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1352
1353 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1354 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1355
1356 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1357
1358 <dd>Perform the <a href="#i_extractelement">extractelement
1359 operation</a> on constants.
1360
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1361 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1362
1363 <dd>Perform the <a href="#i_insertelement">insertelement
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1364 operation</a> on constants.</dd>
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1365
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1366
1367 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1368
1369 <dd>Perform the <a href="#i_shufflevector">shufflevector
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1370 operation</a> on constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1371
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1372 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1373
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1374 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1375 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1376 binary</a> operations. The constraints on operands are the same as those for
1377 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1378 values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1379</dl>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1380</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]1381
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1382<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1383<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1384<!-- *********************************************************************** -->
1385
1386<!-- ======================================================================= -->
1387<div class="doc_subsection">
1388<a name="inlineasm">Inline Assembler Expressions</a>
1389</div>
1390
1391<div class="doc_text">
1392
1393<p>
1394LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1395Module-Level Inline Assembly</a>) through the use of a special value. This
1396value represents the inline assembler as a string (containing the instructions
1397to emit), a list of operand constraints (stored as a string), and a flag that
1398indicates whether or not the inline asm expression has side effects. An example
1399inline assembler expression is:
1400</p>
1401
1402<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1403 i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1404</pre>
1405
1406<p>
1407Inline assembler expressions may <b>only</b> be used as the callee operand of
1408a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1409</p>
1410
1411<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1412 %X = call i32 asm "<a href="#i_bswap">bswap</a> $0", "=r,r"(i32 %Y)
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1413</pre>
1414
1415<p>
1416Inline asms with side effects not visible in the constraint list must be marked
1417as having side effects. This is done through the use of the
1418'<tt>sideeffect</tt>' keyword, like so:
1419</p>
1420
1421<pre>
1422 call void asm sideeffect "eieio", ""()
1423</pre>
1424
1425<p>TODO: The format of the asm and constraints string still need to be
1426documented here. Constraints on what can be done (e.g. duplication, moving, etc
1427need to be documented).
1428</p>
1429
1430</div>
1431
1432<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1433<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1434<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1435
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1436<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1437
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1438<p>The LLVM instruction set consists of several different
1439classifications of instructions: <a href="#terminators">terminator
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1440instructions</a>, <a href="#binaryops">binary instructions</a>,
1441<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1442 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1443instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1444
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1445</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1446
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1447<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1448<div class="doc_subsection"> <a name="terminators">Terminator
1449Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1450
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1451<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1452
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1453<p>As mentioned <a href="#functionstructure">previously</a>, every
1454basic block in a program ends with a "Terminator" instruction, which
1455indicates which block should be executed after the current block is
1456finished. These terminator instructions typically yield a '<tt>void</tt>'
1457value: they produce control flow, not values (the one exception being
1458the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1459<p>There are six different terminator instructions: the '<a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1460 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1461instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1462the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1463 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1464 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1465
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1466</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1467
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1468<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1469<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1470Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1471<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1472<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1473<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]1474 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1475</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1476<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1477<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1478value) from a function back to the caller.</p>
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]1479<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1480returns a value and then causes control flow, and one that just causes
1481control flow to occur.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1482<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1483<p>The '<tt>ret</tt>' instruction may return any '<a
1484 href="#t_firstclass">first class</a>' type. Notice that a function is
1485not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
1486instruction inside of the function that returns a value that does not
1487match the return type of the function.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1488<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1489<p>When the '<tt>ret</tt>' instruction is executed, control flow
1490returns back to the calling function's context. If the caller is a "<a
John Criswellfa081872004-06-25 15:16:57 +0000[diff] [blame]1491 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1492the instruction after the call. If the caller was an "<a
1493 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1494at the beginning of the "normal" destination block. If the instruction
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1495returns a value, that value shall set the call or invoke instruction's
1496return value.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1497<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1498<pre> ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1499 ret void <i>; Return from a void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1500</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1501</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1502<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1503<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1504<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1505<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1506<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]1507</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1508<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1509<p>The '<tt>br</tt>' instruction is used to cause control flow to
1510transfer to a different basic block in the current function. There are
1511two forms of this instruction, corresponding to a conditional branch
1512and an unconditional branch.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1513<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1514<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
1515single '<tt>bool</tt>' value and two '<tt>label</tt>' values. The
1516unconditional form of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>'
1517value as a target.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1518<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1519<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>bool</tt>'
1520argument is evaluated. If the value is <tt>true</tt>, control flows
1521to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1522control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1523<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1524<pre>Test:<br> %cond = <a href="#i_icmp">icmp</a> eq, i32 %a, %b<br> br bool %cond, label %IfEqual, label %IfUnequal<br>IfEqual:<br> <a
1525 href="#i_ret">ret</a> i32 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> i32 0<br></pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1526</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1527<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1528<div class="doc_subsubsection">
1529 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1530</div>
1531
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1532<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1533<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1534
1535<pre>
1536 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1537</pre>
1538
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1539<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1540
1541<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1542several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1543instruction, allowing a branch to occur to one of many possible
1544destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1545
1546
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1547<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1548
1549<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1550comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1551an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1552table is not allowed to contain duplicate constant entries.</p>
1553
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1554<h5>Semantics:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1555
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1556<p>The <tt>switch</tt> instruction specifies a table of values and
1557destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1558table is searched for the given value. If the value is found, control flow is
1559transfered to the corresponding destination; otherwise, control flow is
1560transfered to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1561
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1562<h5>Implementation:</h5>
1563
1564<p>Depending on properties of the target machine and the particular
1565<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1566ways. For example, it could be generated as a series of chained conditional
1567branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1568
1569<h5>Example:</h5>
1570
1571<pre>
1572 <i>; Emulate a conditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1573 %Val = <a href="#i_zext">zext</a> bool %value to i32
1574 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1575
1576 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1577 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1578
1579 <i>; Implement a jump table:</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1580 switch i32 %val, label %otherwise [ i32 0, label %onzero
1581 i32 1, label %onone
1582 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1583</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1584</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1585
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1586<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1587<div class="doc_subsubsection">
1588 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1589</div>
1590
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1591<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1592
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1593<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1594
1595<pre>
1596 &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]1597 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1598</pre>
1599
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1600<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1601
1602<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1603function, with the possibility of control flow transfer to either the
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1604'<tt>normal</tt>' label or the
1605'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1606"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1607"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1608href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
1609continued at the dynamically nearest "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1610
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1611<h5>Arguments:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1612
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1613<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1614
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1615<ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1616 <li>
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1617 The optional "cconv" marker indicates which <a href="callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1618 convention</a> the call should use. If none is specified, the call defaults
1619 to using C calling conventions.
1620 </li>
1621 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1622 function value being invoked. In most cases, this is a direct function
1623 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1624 an arbitrary pointer to function value.
1625 </li>
1626
1627 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1628 function to be invoked. </li>
1629
1630 <li>'<tt>function args</tt>': argument list whose types match the function
1631 signature argument types. If the function signature indicates the function
1632 accepts a variable number of arguments, the extra arguments can be
1633 specified. </li>
1634
1635 <li>'<tt>normal label</tt>': the label reached when the called function
1636 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1637
1638 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1639 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1640
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1641</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1642
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1643<h5>Semantics:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1644
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1645<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1646href="#i_call">call</a></tt>' instruction in most regards. The primary
1647difference is that it establishes an association with a label, which is used by
1648the runtime library to unwind the stack.</p>
1649
1650<p>This instruction is used in languages with destructors to ensure that proper
1651cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1652exception. Additionally, this is important for implementation of
1653'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1654
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1655<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1656<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1657 %retval = invoke i32 %Test(i32 15) to label %Continue
1658 unwind label %TestCleanup <i>; {i32}:retval set</i>
1659 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Test(i32 15) to label %Continue
1660 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1661</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1662</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1663
1664
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1665<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1666
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1667<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1668Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1669
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1670<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1671
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1672<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1673<pre>
1674 unwind
1675</pre>
1676
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1677<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1678
1679<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
1680at the first callee in the dynamic call stack which used an <a
1681href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
1682primarily used to implement exception handling.</p>
1683
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1684<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1685
1686<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
1687immediately halt. The dynamic call stack is then searched for the first <a
1688href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
1689execution continues at the "exceptional" destination block specified by the
1690<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
1691dynamic call chain, undefined behavior results.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1692</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1693
1694<!-- _______________________________________________________________________ -->
1695
1696<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
1697Instruction</a> </div>
1698
1699<div class="doc_text">
1700
1701<h5>Syntax:</h5>
1702<pre>
1703 unreachable
1704</pre>
1705
1706<h5>Overview:</h5>
1707
1708<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
1709instruction is used to inform the optimizer that a particular portion of the
1710code is not reachable. This can be used to indicate that the code after a
1711no-return function cannot be reached, and other facts.</p>
1712
1713<h5>Semantics:</h5>
1714
1715<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
1716</div>
1717
1718
1719
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1720<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1721<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1722<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1723<p>Binary operators are used to do most of the computation in a
1724program. They require two operands, execute an operation on them, and
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1725produce a single value. The operands might represent
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1726multiple data, as is the case with the <a href="#t_packed">packed</a> data type.
1727The result value of a binary operator is not
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1728necessarily the same type as its operands.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1729<p>There are several different binary operators:</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1730</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1731<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1732<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
1733Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1734<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1735<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1736<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]1737</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1738<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1739<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1740<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1741<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1742 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
1743 This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1744Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1745<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1746<p>The value produced is the integer or floating point sum of the two
1747operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1748<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1749<pre> &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1750</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1751</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1752<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1753<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
1754Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1755<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1756<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1757<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]1758</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1759<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1760<p>The '<tt>sub</tt>' instruction returns the difference of its two
1761operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1762<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
1763instruction present in most other intermediate representations.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1764<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1765<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1766 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1767values.
1768This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1769Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1770<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1771<p>The value produced is the integer or floating point difference of
1772the two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1773<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1774<pre> &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
1775 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1776</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1777</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1778<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1779<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
1780Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1781<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1782<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1783<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]1784</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1785<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1786<p>The '<tt>mul</tt>' instruction returns the product of its two
1787operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1788<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1789<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1790 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1791values.
1792This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1793Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1794<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1795<p>The value produced is the integer or floating point product of the
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1796two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1797<p>There is no signed vs unsigned multiplication. The appropriate
1798action is taken based on the type of the operand.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1799<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1800<pre> &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1801</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1802</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1803<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1804<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
1805</a></div>
1806<div class="doc_text">
1807<h5>Syntax:</h5>
1808<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1809</pre>
1810<h5>Overview:</h5>
1811<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
1812operands.</p>
1813<h5>Arguments:</h5>
1814<p>The two arguments to the '<tt>udiv</tt>' instruction must be
1815<a href="#t_integer">integer</a> values. Both arguments must have identical
1816types. This instruction can also take <a href="#t_packed">packed</a> versions
1817of the values in which case the elements must be integers.</p>
1818<h5>Semantics:</h5>
1819<p>The value produced is the unsigned integer quotient of the two operands. This
1820instruction always performs an unsigned division operation, regardless of
1821whether the arguments are unsigned or not.</p>
1822<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1823<pre> &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1824</pre>
1825</div>
1826<!-- _______________________________________________________________________ -->
1827<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
1828</a> </div>
1829<div class="doc_text">
1830<h5>Syntax:</h5>
1831<pre> &lt;result&gt; = sdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1832</pre>
1833<h5>Overview:</h5>
1834<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
1835operands.</p>
1836<h5>Arguments:</h5>
1837<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
1838<a href="#t_integer">integer</a> values. Both arguments must have identical
1839types. This instruction can also take <a href="#t_packed">packed</a> versions
1840of the values in which case the elements must be integers.</p>
1841<h5>Semantics:</h5>
1842<p>The value produced is the signed integer quotient of the two operands. This
1843instruction always performs a signed division operation, regardless of whether
1844the arguments are signed or not.</p>
1845<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1846<pre> &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1847</pre>
1848</div>
1849<!-- _______________________________________________________________________ -->
1850<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1851Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1852<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1853<h5>Syntax:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1854<pre> &lt;result&gt; = fdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1855</pre>
1856<h5>Overview:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1857<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1858operands.</p>
1859<h5>Arguments:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1860<p>The two arguments to the '<tt>div</tt>' instruction must be
1861<a href="#t_floating">floating point</a> values. Both arguments must have
1862identical types. This instruction can also take <a href="#t_packed">packed</a>
1863versions of the values in which case the elements must be floating point.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1864<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1865<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1866<h5>Example:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1867<pre> &lt;result&gt; = fdiv float 4.0, %var <i>; yields {float}:result = 4.0 / %var</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1868</pre>
1869</div>
1870<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1871<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
1872</div>
1873<div class="doc_text">
1874<h5>Syntax:</h5>
1875<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1876</pre>
1877<h5>Overview:</h5>
1878<p>The '<tt>urem</tt>' instruction returns the remainder from the
1879unsigned division of its two arguments.</p>
1880<h5>Arguments:</h5>
1881<p>The two arguments to the '<tt>urem</tt>' instruction must be
1882<a href="#t_integer">integer</a> values. Both arguments must have identical
1883types.</p>
1884<h5>Semantics:</h5>
1885<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
1886This instruction always performs an unsigned division to get the remainder,
1887regardless of whether the arguments are unsigned or not.</p>
1888<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1889<pre> &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1890</pre>
1891
1892</div>
1893<!-- _______________________________________________________________________ -->
1894<div class="doc_subsubsection"> <a name="i_srem">'<tt>srem</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1895Instruction</a> </div>
1896<div class="doc_text">
1897<h5>Syntax:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1898<pre> &lt;result&gt; = srem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1899</pre>
1900<h5>Overview:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1901<p>The '<tt>srem</tt>' instruction returns the remainder from the
1902signed division of its two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1903<h5>Arguments:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1904<p>The two arguments to the '<tt>srem</tt>' instruction must be
1905<a href="#t_integer">integer</a> values. Both arguments must have identical
1906types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1907<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1908<p>This instruction returns the <i>remainder</i> of a division (where the result
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1909has the same sign as the divisor), not the <i>modulus</i> (where the
1910result has the same sign as the dividend) of a value. For more
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1911information about the difference, see <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1912 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
1913Math Forum</a>.</p>
1914<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1915<pre> &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1916</pre>
1917
1918</div>
1919<!-- _______________________________________________________________________ -->
1920<div class="doc_subsubsection"> <a name="i_frem">'<tt>frem</tt>'
1921Instruction</a> </div>
1922<div class="doc_text">
1923<h5>Syntax:</h5>
1924<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1925</pre>
1926<h5>Overview:</h5>
1927<p>The '<tt>frem</tt>' instruction returns the remainder from the
1928division of its two operands.</p>
1929<h5>Arguments:</h5>
1930<p>The two arguments to the '<tt>frem</tt>' instruction must be
1931<a href="#t_floating">floating point</a> values. Both arguments must have
1932identical types.</p>
1933<h5>Semantics:</h5>
1934<p>This instruction returns the <i>remainder</i> of a division.</p>
1935<h5>Example:</h5>
1936<pre> &lt;result&gt; = frem float 4.0, %var <i>; yields {float}:result = 4.0 % %var</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1937</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1938</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]1939
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1940<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1941<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
1942Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1943<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1944<p>Bitwise binary operators are used to do various forms of
1945bit-twiddling in a program. They are generally very efficient
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1946instructions and can commonly be strength reduced from other
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1947instructions. They require two operands, execute an operation on them,
1948and produce a single value. The resulting value of the bitwise binary
1949operators is always the same type as its first operand.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1950</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1951<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1952<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
1953Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1954<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1955<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1956<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]1957</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1958<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1959<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
1960its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1961<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1962<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1963 href="#t_integral">integral</a> values. Both arguments must have
1964identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1965<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1966<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1967<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1968<div style="align: center">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1969<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1970 <tbody>
1971 <tr>
1972 <td>In0</td>
1973 <td>In1</td>
1974 <td>Out</td>
1975 </tr>
1976 <tr>
1977 <td>0</td>
1978 <td>0</td>
1979 <td>0</td>
1980 </tr>
1981 <tr>
1982 <td>0</td>
1983 <td>1</td>
1984 <td>0</td>
1985 </tr>
1986 <tr>
1987 <td>1</td>
1988 <td>0</td>
1989 <td>0</td>
1990 </tr>
1991 <tr>
1992 <td>1</td>
1993 <td>1</td>
1994 <td>1</td>
1995 </tr>
1996 </tbody>
1997</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1998</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1999<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2000<pre> &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
2001 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2002 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2003</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2004</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2005<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2006<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2007<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2008<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2009<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]2010</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2011<h5>Overview:</h5>
2012<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2013or of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2014<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2015<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2016 href="#t_integral">integral</a> values. Both arguments must have
2017identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2018<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2019<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2020<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2021<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2022<table border="1" cellspacing="0" cellpadding="4">
2023 <tbody>
2024 <tr>
2025 <td>In0</td>
2026 <td>In1</td>
2027 <td>Out</td>
2028 </tr>
2029 <tr>
2030 <td>0</td>
2031 <td>0</td>
2032 <td>0</td>
2033 </tr>
2034 <tr>
2035 <td>0</td>
2036 <td>1</td>
2037 <td>1</td>
2038 </tr>
2039 <tr>
2040 <td>1</td>
2041 <td>0</td>
2042 <td>1</td>
2043 </tr>
2044 <tr>
2045 <td>1</td>
2046 <td>1</td>
2047 <td>1</td>
2048 </tr>
2049 </tbody>
2050</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2051</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2052<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2053<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2054 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2055 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2056</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2057</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2058<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2059<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2060Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2061<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2062<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2063<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]2064</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2065<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2066<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2067or of its two operands. The <tt>xor</tt> is used to implement the
2068"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2069<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2070<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2071 href="#t_integral">integral</a> values. Both arguments must have
2072identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2073<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2074<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2075<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2076<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2077<table border="1" cellspacing="0" cellpadding="4">
2078 <tbody>
2079 <tr>
2080 <td>In0</td>
2081 <td>In1</td>
2082 <td>Out</td>
2083 </tr>
2084 <tr>
2085 <td>0</td>
2086 <td>0</td>
2087 <td>0</td>
2088 </tr>
2089 <tr>
2090 <td>0</td>
2091 <td>1</td>
2092 <td>1</td>
2093 </tr>
2094 <tr>
2095 <td>1</td>
2096 <td>0</td>
2097 <td>1</td>
2098 </tr>
2099 <tr>
2100 <td>1</td>
2101 <td>1</td>
2102 <td>0</td>
2103 </tr>
2104 </tbody>
2105</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2106</div>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2107<p> </p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2108<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2109<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2110 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2111 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2112 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2113</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2114</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2115<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2116<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2117Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2118<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2119<h5>Syntax:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2120<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, i8 &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2121</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2122<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2123<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2124the left a specified number of bits.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2125<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2126<p>The first argument to the '<tt>shl</tt>' instruction must be an <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2127 href="#t_integer">integer</a> type. The second argument must be an '<tt>i8</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2128type.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2129<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2130<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]2131<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2132<pre> &lt;result&gt; = shl i32 4, i8 %var <i>; yields {i32}:result = 4 &lt;&lt; %var</i>
2133 &lt;result&gt; = shl i32 4, i8 2 <i>; yields {i32}:result = 16</i>
2134 &lt;result&gt; = shl i32 1, i8 10 <i>; yields {i32}:result = 1024</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2135</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2136</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2137<!-- _______________________________________________________________________ -->
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2138<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2139Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2140<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2141<h5>Syntax:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2142<pre> &lt;result&gt; = lshr &lt;ty&gt; &lt;var1&gt;, i8 &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2143</pre>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2144
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2145<h5>Overview:</h5>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2146<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
2147operand shifted to the right a specified number of bits.</p>
2148
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2149<h5>Arguments:</h5>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2150<p>The first argument to the '<tt>lshr</tt>' instruction must be an <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2151 href="#t_integer">integer</a> type. The second argument must be an '<tt>i8</tt>' type.</p>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2152
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2153<h5>Semantics:</h5>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2154<p>This instruction always performs a logical shift right operation, regardless
2155of whether the arguments are unsigned or not. The <tt>var2</tt> most significant
2156bits will be filled with zero bits after the shift.</p>
2157
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2158<h5>Example:</h5>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2159<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2160 &lt;result&gt; = lshr i32 4, i8 1 <i>; yields {i32}:result = 2</i>
2161 &lt;result&gt; = lshr i32 4, i8 2 <i>; yields {i32}:result = 1</i>
2162 &lt;result&gt; = lshr i8 4, i8 3 <i>; yields {i8 }:result = 0</i>
2163 &lt;result&gt; = lshr i8 -2, i8 1 <i>; yields {i8 }:result = 0x7FFFFFFF </i>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2164</pre>
2165</div>
2166
2167<!-- ======================================================================= -->
2168<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2169Instruction</a> </div>
2170<div class="doc_text">
2171
2172<h5>Syntax:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2173<pre> &lt;result&gt; = ashr &lt;ty&gt; &lt;var1&gt;, i8 &lt;var2&gt; <i>; yields {ty}:result</i>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2174</pre>
2175
2176<h5>Overview:</h5>
2177<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
2178operand shifted to the right a specified number of bits.</p>
2179
2180<h5>Arguments:</h5>
2181<p>The first argument to the '<tt>ashr</tt>' instruction must be an
2182<a href="#t_integer">integer</a> type. The second argument must be an
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2183'<tt>i8</tt>' type.</p>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2184
2185<h5>Semantics:</h5>
2186<p>This instruction always performs an arithmetic shift right operation,
2187regardless of whether the arguments are signed or not. The <tt>var2</tt> most
2188significant bits will be filled with the sign bit of <tt>var1</tt>.</p>
2189
2190<h5>Example:</h5>
2191<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2192 &lt;result&gt; = ashr i32 4, i8 1 <i>; yields {i32}:result = 2</i>
2193 &lt;result&gt; = ashr i32 4, i8 2 <i>; yields {i32}:result = 1</i>
2194 &lt;result&gt; = ashr i8 4, i8 3 <i>; yields {i8}:result = 0</i>
2195 &lt;result&gt; = ashr i8 -2, i8 1 <i>; yields {i8 }:result = -1</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2196</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2197</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2198
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2199<!-- ======================================================================= -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2200<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2201 <a name="vectorops">Vector Operations</a>
2202</div>
2203
2204<div class="doc_text">
2205
2206<p>LLVM supports several instructions to represent vector operations in a
2207target-independent manner. This instructions cover the element-access and
2208vector-specific operations needed to process vectors effectively. While LLVM
2209does directly support these vector operations, many sophisticated algorithms
2210will want to use target-specific intrinsics to take full advantage of a specific
2211target.</p>
2212
2213</div>
2214
2215<!-- _______________________________________________________________________ -->
2216<div class="doc_subsubsection">
2217 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2218</div>
2219
2220<div class="doc_text">
2221
2222<h5>Syntax:</h5>
2223
2224<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2225 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2226</pre>
2227
2228<h5>Overview:</h5>
2229
2230<p>
2231The '<tt>extractelement</tt>' instruction extracts a single scalar
2232element from a packed vector at a specified index.
2233</p>
2234
2235
2236<h5>Arguments:</h5>
2237
2238<p>
2239The first operand of an '<tt>extractelement</tt>' instruction is a
2240value of <a href="#t_packed">packed</a> type. The second operand is
2241an index indicating the position from which to extract the element.
2242The index may be a variable.</p>
2243
2244<h5>Semantics:</h5>
2245
2246<p>
2247The result is a scalar of the same type as the element type of
2248<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2249<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2250results are undefined.
2251</p>
2252
2253<h5>Example:</h5>
2254
2255<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2256 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2257</pre>
2258</div>
2259
2260
2261<!-- _______________________________________________________________________ -->
2262<div class="doc_subsubsection">
2263 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2264</div>
2265
2266<div class="doc_text">
2267
2268<h5>Syntax:</h5>
2269
2270<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2271 &lt;result&gt; = insertelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, &lt;ty&gt; &lt;elt&gt, i32 &lt;idx&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2272</pre>
2273
2274<h5>Overview:</h5>
2275
2276<p>
2277The '<tt>insertelement</tt>' instruction inserts a scalar
2278element into a packed vector at a specified index.
2279</p>
2280
2281
2282<h5>Arguments:</h5>
2283
2284<p>
2285The first operand of an '<tt>insertelement</tt>' instruction is a
2286value of <a href="#t_packed">packed</a> type. The second operand is a
2287scalar value whose type must equal the element type of the first
2288operand. The third operand is an index indicating the position at
2289which to insert the value. The index may be a variable.</p>
2290
2291<h5>Semantics:</h5>
2292
2293<p>
2294The result is a packed vector of the same type as <tt>val</tt>. Its
2295element values are those of <tt>val</tt> except at position
2296<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2297exceeds the length of <tt>val</tt>, the results are undefined.
2298</p>
2299
2300<h5>Example:</h5>
2301
2302<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2303 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2304</pre>
2305</div>
2306
2307<!-- _______________________________________________________________________ -->
2308<div class="doc_subsubsection">
2309 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2310</div>
2311
2312<div class="doc_text">
2313
2314<h5>Syntax:</h5>
2315
2316<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2317 &lt;result&gt; = shufflevector &lt;n x &lt;ty&gt;&gt; &lt;v1&gt;, &lt;n x &lt;ty&gt;&gt; &lt;v2&gt;, &lt;n x i32&gt; &lt;mask&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2318</pre>
2319
2320<h5>Overview:</h5>
2321
2322<p>
2323The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2324from two input vectors, returning a vector of the same type.
2325</p>
2326
2327<h5>Arguments:</h5>
2328
2329<p>
2330The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2331with types that match each other and types that match the result of the
2332instruction. The third argument is a shuffle mask, which has the same number
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2333of elements as the other vector type, but whose element type is always 'i32'.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2334</p>
2335
2336<p>
2337The shuffle mask operand is required to be a constant vector with either
2338constant integer or undef values.
2339</p>
2340
2341<h5>Semantics:</h5>
2342
2343<p>
2344The elements of the two input vectors are numbered from left to right across
2345both of the vectors. The shuffle mask operand specifies, for each element of
2346the result vector, which element of the two input registers the result element
2347gets. The element selector may be undef (meaning "don't care") and the second
2348operand may be undef if performing a shuffle from only one vector.
2349</p>
2350
2351<h5>Example:</h5>
2352
2353<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2354 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
2355 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
2356 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2357 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i> - Identity shuffle.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2358</pre>
2359</div>
2360
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]2361
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2362<!-- ======================================================================= -->
2363<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2364 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2365</div>
2366
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2367<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2368
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2369<p>A key design point of an SSA-based representation is how it
2370represents memory. In LLVM, no memory locations are in SSA form, which
2371makes things very simple. This section describes how to read, write,
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2372allocate, and free memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2373
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2374</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2375
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2376<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2377<div class="doc_subsubsection">
2378 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2379</div>
2380
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2381<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2382
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2383<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2384
2385<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2386 &lt;result&gt; = malloc &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2387</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2388
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2389<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2390
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2391<p>The '<tt>malloc</tt>' instruction allocates memory from the system
2392heap and returns a pointer to it.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2393
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2394<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2395
2396<p>The '<tt>malloc</tt>' instruction allocates
2397<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswell6e4ca612004-02-24 16:13:56 +0000[diff] [blame]2398bytes of memory from the operating system and returns a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2399appropriate type to the program. If "NumElements" is specified, it is the
2400number of elements allocated. If an alignment is specified, the value result
2401of the allocation is guaranteed to be aligned to at least that boundary. If
2402not specified, or if zero, the target can choose to align the allocation on any
2403convenient boundary.</p>
2404
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2405<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2406
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2407<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2408
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2409<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
2410a pointer is returned.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2411
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2412<h5>Example:</h5>
2413
2414<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2415 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2416
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2417 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
2418 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
2419 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
2420 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
2421 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2422</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2423</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2424
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2425<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2426<div class="doc_subsubsection">
2427 <a name="i_free">'<tt>free</tt>' Instruction</a>
2428</div>
2429
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2430<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2431
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2432<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2433
2434<pre>
2435 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2436</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2437
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2438<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2439
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2440<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2441memory heap to be reallocated in the future.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2442
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2443<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2444
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2445<p>'<tt>value</tt>' shall be a pointer value that points to a value
2446that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
2447instruction.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2448
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2449<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2450
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2451<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2452after this instruction executes.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2453
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2454<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2455
2456<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2457 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
2458 free [4 x i8]* %array
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2459</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2460</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2461
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2462<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2463<div class="doc_subsubsection">
2464 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
2465</div>
2466
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2467<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2468
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2469<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2470
2471<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2472 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2473</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2474
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2475<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2476
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2477<p>The '<tt>alloca</tt>' instruction allocates memory on the current
2478stack frame of the procedure that is live until the current function
2479returns to its caller.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2480
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2481<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2482
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2483<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2484bytes of memory on the runtime stack, returning a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2485appropriate type to the program. If "NumElements" is specified, it is the
2486number of elements allocated. If an alignment is specified, the value result
2487of the allocation is guaranteed to be aligned to at least that boundary. If
2488not specified, or if zero, the target can choose to align the allocation on any
2489convenient boundary.</p>
2490
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2491<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2492
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2493<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2494
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2495<p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2496memory is automatically released when the function returns. The '<tt>alloca</tt>'
2497instruction is commonly used to represent automatic variables that must
2498have an address available. When the function returns (either with the <tt><a
John Criswelldae2e932005-05-12 16:55:34 +0000[diff] [blame]2499 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]2500instructions), the memory is reclaimed.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2501
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2502<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2503
2504<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2505 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
2506 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
2507 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
2508 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2509</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2510</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2511
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2512<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2513<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
2514Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2515<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2516<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2517<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]2518<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2519<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2520<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2521<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2522address from which to load. The pointer must point to a <a
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]2523 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2524marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2525the number or order of execution of this <tt>load</tt> with other
2526volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
2527instructions. </p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2528<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2529<p>The location of memory pointed to is loaded.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2530<h5>Examples:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2531<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2532 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2533 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2534 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2535</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2536</div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2537<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2538<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
2539Instruction</a> </div>
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]2540<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2541<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2542<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]2543 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]2544</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2545<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2546<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2547<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2548<p>There are two arguments to the '<tt>store</tt>' instruction: a value
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2549to 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]2550operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2551operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2552optimizer is not allowed to modify the number or order of execution of
2553this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
2554 href="#i_store">store</a></tt> instructions.</p>
2555<h5>Semantics:</h5>
2556<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
2557at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2558<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2559<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2560 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2561 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2562 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2563</pre>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2564</div>
2565
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2566<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2567<div class="doc_subsubsection">
2568 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
2569</div>
2570
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2571<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2572<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2573<pre>
2574 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
2575</pre>
2576
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2577<h5>Overview:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2578
2579<p>
2580The '<tt>getelementptr</tt>' instruction is used to get the address of a
2581subelement of an aggregate data structure.</p>
2582
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2583<h5>Arguments:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2584
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2585<p>This instruction takes a list of integer operands that indicate what
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2586elements of the aggregate object to index to. The actual types of the arguments
2587provided depend on the type of the first pointer argument. The
2588'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2589levels of a structure or to a specific index in an array. When indexing into a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2590structure, only <tt>i32</tt> integer constants are allowed. When indexing
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2591into an array or pointer, only integers of 32 or 64 bits are allowed, and will
2592be sign extended to 64-bit values.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2593
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2594<p>For example, let's consider a C code fragment and how it gets
2595compiled to LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2596
2597<pre>
2598 struct RT {
2599 char A;
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2600 i32 B[10][20];
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2601 char C;
2602 };
2603 struct ST {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2604 i32 X;
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2605 double Y;
2606 struct RT Z;
2607 };
2608
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2609 define i32 *foo(struct ST *s) {
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2610 return &amp;s[1].Z.B[5][13];
2611 }
2612</pre>
2613
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2614<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2615
2616<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2617 %RT = type { i8 , [10 x [20 x i32]], i8 }
2618 %ST = type { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2619
Brian Gaeke7283e7c2004-07-02 21:08:14 +0000[diff] [blame]2620 implementation
2621
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2622 define i32* %foo(%ST* %s) {
Brian Gaeke7283e7c2004-07-02 21:08:14 +0000[diff] [blame]2623 entry:
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2624 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
2625 ret i32* %reg
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2626 }
2627</pre>
2628
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2629<h5>Semantics:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2630
2631<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2632on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2633and <a href="#t_array">array</a> types can use a 32-bit or 64-bit
Reid Spencer42ddd842006-12-03 16:53:48 +0000[diff] [blame]2634<a href="#t_integer">integer</a> type but the value will always be sign extended
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2635to 64-bits. <a href="#t_struct">Structure</a> types, require <tt>i32</tt>
Reid Spencer42ddd842006-12-03 16:53:48 +0000[diff] [blame]2636<b>constants</b>.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2637
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2638<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2639type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2640}</tt>' type, a structure. The second index indexes into the third element of
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2641the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
2642i8 }</tt>' type, another structure. The third index indexes into the second
2643element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2644array. The two dimensions of the array are subscripted into, yielding an
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2645'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
2646to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2647
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2648<p>Note that it is perfectly legal to index partially through a
2649structure, returning a pointer to an inner element. Because of this,
2650the LLVM code for the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2651
2652<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2653 define i32* %foo(%ST* %s) {
2654 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
2655 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
2656 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
2657 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
2658 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
2659 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2660 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2661</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2662
2663<p>Note that it is undefined to access an array out of bounds: array and
2664pointer indexes must always be within the defined bounds of the array type.
2665The one exception for this rules is zero length arrays. These arrays are
2666defined to be accessible as variable length arrays, which requires access
2667beyond the zero'th element.</p>
2668
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2669<p>The getelementptr instruction is often confusing. For some more insight
2670into how it works, see <a href="GetElementPtr.html">the getelementptr
2671FAQ</a>.</p>
2672
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2673<h5>Example:</h5>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2674
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2675<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2676 <i>; yields [12 x i8]*:aptr</i>
2677 %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2678</pre>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2679</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2680
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2681<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]2682<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2683</div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2684<div class="doc_text">
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]2685<p>The instructions in this category are the conversion instructions (casting)
2686which all take a single operand and a type. They perform various bit conversions
2687on the operand.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2688</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2689
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2690<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2691<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2692 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
2693</div>
2694<div class="doc_text">
2695
2696<h5>Syntax:</h5>
2697<pre>
2698 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2699</pre>
2700
2701<h5>Overview:</h5>
2702<p>
2703The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
2704</p>
2705
2706<h5>Arguments:</h5>
2707<p>
2708The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
2709be an <a href="#t_integer">integer</a> type, and a type that specifies the size
2710and type of the result, which must be an <a href="#t_integral">integral</a>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2711type. The bit size of <tt>value</tt> must be larger than the bit size of
2712<tt>ty2</tt>. Equal sized types are not allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2713
2714<h5>Semantics:</h5>
2715<p>
2716The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2717and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
2718larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
2719It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2720
2721<h5>Example:</h5>
2722<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2723 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
2724 %Y = trunc i32 123 to bool <i>; yields bool:true</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2725</pre>
2726</div>
2727
2728<!-- _______________________________________________________________________ -->
2729<div class="doc_subsubsection">
2730 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
2731</div>
2732<div class="doc_text">
2733
2734<h5>Syntax:</h5>
2735<pre>
2736 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2737</pre>
2738
2739<h5>Overview:</h5>
2740<p>The '<tt>zext</tt>' instruction zero extends its operand to type
2741<tt>ty2</tt>.</p>
2742
2743
2744<h5>Arguments:</h5>
2745<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
2746<a href="#t_integral">integral</a> type, and a type to cast it to, which must
2747also be of <a href="#t_integral">integral</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2748<tt>value</tt> must be smaller than the bit size of the destination type,
2749<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2750
2751<h5>Semantics:</h5>
2752<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
2753bits until it reaches the size of the destination type, <tt>ty2</tt>. When the
2754the operand and the type are the same size, no bit filling is done and the
2755cast is considered a <i>no-op cast</i> because no bits change (only the type
2756changes).</p>
2757
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2758<p>When zero extending from bool, the result will alwasy be either 0 or 1.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2759
2760<h5>Example:</h5>
2761<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2762 %X = zext i32 257 to i64 <i>; yields i64:257</i>
2763 %Y = zext bool true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2764</pre>
2765</div>
2766
2767<!-- _______________________________________________________________________ -->
2768<div class="doc_subsubsection">
2769 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
2770</div>
2771<div class="doc_text">
2772
2773<h5>Syntax:</h5>
2774<pre>
2775 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2776</pre>
2777
2778<h5>Overview:</h5>
2779<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
2780
2781<h5>Arguments:</h5>
2782<p>
2783The '<tt>sext</tt>' instruction takes a value to cast, which must be of
2784<a href="#t_integral">integral</a> type, and a type to cast it to, which must
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2785also be of <a href="#t_integral">integral</a> type. The bit size of the
2786<tt>value</tt> must be smaller than the bit size of the destination type,
2787<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2788
2789<h5>Semantics:</h5>
2790<p>
2791The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
2792bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
2793the type <tt>ty2</tt>. When the the operand and the type are the same size,
2794no bit filling is done and the cast is considered a <i>no-op cast</i> because
2795no bits change (only the type changes).</p>
2796
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2797<p>When sign extending from bool, the extension always results in -1 or 0.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2798
2799<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2800<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2801 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
2802 %Y = sext bool true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2803</pre>
2804</div>
2805
2806<!-- _______________________________________________________________________ -->
2807<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]2808 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
2809</div>
2810
2811<div class="doc_text">
2812
2813<h5>Syntax:</h5>
2814
2815<pre>
2816 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2817</pre>
2818
2819<h5>Overview:</h5>
2820<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
2821<tt>ty2</tt>.</p>
2822
2823
2824<h5>Arguments:</h5>
2825<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
2826 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
2827cast it to. The size of <tt>value</tt> must be larger than the size of
2828<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
2829<i>no-op cast</i>.</p>
2830
2831<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2832<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
2833<a href="#t_floating">floating point</a> type to a smaller
2834<a href="#t_floating">floating point</a> type. If the value cannot fit within
2835the destination type, <tt>ty2</tt>, then the results are undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]2836
2837<h5>Example:</h5>
2838<pre>
2839 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
2840 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
2841</pre>
2842</div>
2843
2844<!-- _______________________________________________________________________ -->
2845<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2846 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
2847</div>
2848<div class="doc_text">
2849
2850<h5>Syntax:</h5>
2851<pre>
2852 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2853</pre>
2854
2855<h5>Overview:</h5>
2856<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
2857floating point value.</p>
2858
2859<h5>Arguments:</h5>
2860<p>The '<tt>fpext</tt>' instruction takes a
2861<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2862and a <a href="#t_floating">floating point</a> type to cast it to. The source
2863type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2864
2865<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2866<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
2867<a href="t_floating">floating point</a> type to a larger
2868<a href="t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
2869used to make a <i>no-op cast</i> because it always changes bits. Use
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2870<tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2871
2872<h5>Example:</h5>
2873<pre>
2874 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
2875 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
2876</pre>
2877</div>
2878
2879<!-- _______________________________________________________________________ -->
2880<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2881 <a name="i_fp2uint">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2882</div>
2883<div class="doc_text">
2884
2885<h5>Syntax:</h5>
2886<pre>
2887 &lt;result&gt; = fp2uint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2888</pre>
2889
2890<h5>Overview:</h5>
2891<p>The '<tt>fp2uint</tt>' converts a floating point <tt>value</tt> to its
2892unsigned integer equivalent of type <tt>ty2</tt>.
2893</p>
2894
2895<h5>Arguments:</h5>
2896<p>The '<tt>fp2uint</tt>' instruction takes a value to cast, which must be a
2897<a href="#t_floating">floating point</a> value, and a type to cast it to, which
2898must be an <a href="#t_integral">integral</a> type.</p>
2899
2900<h5>Semantics:</h5>
2901<p> The '<tt>fp2uint</tt>' instruction converts its
2902<a href="#t_floating">floating point</a> operand into the nearest (rounding
2903towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
2904the results are undefined.</p>
2905
2906<p>When converting to bool, the conversion is done as a comparison against
2907zero. If the <tt>value</tt> was zero, the bool result will be <tt>false</tt>.
2908If the <tt>value</tt> was non-zero, the bool result will be <tt>true</tt>.</p>
2909
2910<h5>Example:</h5>
2911<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2912 %X = fp2uint double 123.0 to i32 <i>; yields i32:123</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2913 %Y = fp2uint float 1.0E+300 to bool <i>; yields bool:true</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2914 %X = fp2uint float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2915</pre>
2916</div>
2917
2918<!-- _______________________________________________________________________ -->
2919<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2920 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2921</div>
2922<div class="doc_text">
2923
2924<h5>Syntax:</h5>
2925<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2926 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2927</pre>
2928
2929<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2930<p>The '<tt>fptosi</tt>' instruction converts
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2931<a href="#t_floating">floating point</a> <tt>value</tt> to type <tt>ty2</tt>.
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2932</p>
2933
2934
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2935<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2936<p> The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2937<a href="#t_floating">floating point</a> value, and a type to cast it to, which
2938must also be an <a href="#t_integral">integral</a> type.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2939
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2940<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2941<p>The '<tt>fptosi</tt>' instruction converts its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2942<a href="#t_floating">floating point</a> operand into the nearest (rounding
2943towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
2944the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2945
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2946<p>When converting to bool, the conversion is done as a comparison against
2947zero. If the <tt>value</tt> was zero, the bool result will be <tt>false</tt>.
2948If the <tt>value</tt> was non-zero, the bool result will be <tt>true</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2949
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2950<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2951<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2952 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2953 %Y = fptosi float 1.0E-247 to bool <i>; yields bool:true</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2954 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2955</pre>
2956</div>
2957
2958<!-- _______________________________________________________________________ -->
2959<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2960 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2961</div>
2962<div class="doc_text">
2963
2964<h5>Syntax:</h5>
2965<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2966 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2967</pre>
2968
2969<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2970<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2971integer and converts that value to the <tt>ty2</tt> type.</p>
2972
2973
2974<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2975<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be an
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2976<a href="#t_integral">integral</a> value, and a type to cast it to, which must
2977be a <a href="#t_floating">floating point</a> type.</p>
2978
2979<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2980<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2981integer quantity and converts it to the corresponding floating point value. If
2982the value cannot fit in the floating point value, the results are undefined.</p>
2983
2984
2985<h5>Example:</h5>
2986<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2987 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
2988 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2989</pre>
2990</div>
2991
2992<!-- _______________________________________________________________________ -->
2993<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2994 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2995</div>
2996<div class="doc_text">
2997
2998<h5>Syntax:</h5>
2999<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3000 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3001</pre>
3002
3003<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3004<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3005integer and converts that value to the <tt>ty2</tt> type.</p>
3006
3007<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3008<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be an
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3009<a href="#t_integral">integral</a> value, and a type to cast it to, which must be
3010a <a href="#t_floating">floating point</a> type.</p>
3011
3012<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3013<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3014integer quantity and converts it to the corresponding floating point value. If
3015the value cannot fit in the floating point value, the results are undefined.</p>
3016
3017<h5>Example:</h5>
3018<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3019 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
3020 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3021</pre>
3022</div>
3023
3024<!-- _______________________________________________________________________ -->
3025<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3026 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3027</div>
3028<div class="doc_text">
3029
3030<h5>Syntax:</h5>
3031<pre>
3032 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3033</pre>
3034
3035<h5>Overview:</h5>
3036<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3037the integer type <tt>ty2</tt>.</p>
3038
3039<h5>Arguments:</h5>
3040<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
3041must be a <a href="t_pointer">pointer</a> value, and a type to cast it to
3042<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
3043
3044<h5>Semantics:</h5>
3045<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3046<tt>ty2</tt> by interpreting the pointer value as an integer and either
3047truncating or zero extending that value to the size of the integer type. If
3048<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3049<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
3050are the same size, then nothing is done (<i>no-op cast</i>).</p>
3051
3052<h5>Example:</h5>
3053<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3054 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit</i>
3055 %Y = ptrtoint i32* %x to i64 <i>; yields zero extend on 32-bit</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3056</pre>
3057</div>
3058
3059<!-- _______________________________________________________________________ -->
3060<div class="doc_subsubsection">
3061 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3062</div>
3063<div class="doc_text">
3064
3065<h5>Syntax:</h5>
3066<pre>
3067 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3068</pre>
3069
3070<h5>Overview:</h5>
3071<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3072a pointer type, <tt>ty2</tt>.</p>
3073
3074<h5>Arguments:</h5>
3075<p>The '<tt>inttoptr</tt>' instruction takes an <a href="i_integer">integer</a>
3076value to cast, and a type to cast it to, which must be a
3077<a href="#t_pointer">pointer</a> type. </tt>
3078
3079<h5>Semantics:</h5>
3080<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3081<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3082the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3083size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3084the size of a pointer then a zero extension is done. If they are the same size,
3085nothing is done (<i>no-op cast</i>).</p>
3086
3087<h5>Example:</h5>
3088<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3089 %X = inttoptr i32 255 to i32* <i>; yields zero extend on 64-bit</i>
3090 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit </i>
3091 %Y = inttoptr i16 0 to i32* <i>; yields zero extend on 32-bit</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3092</pre>
3093</div>
3094
3095<!-- _______________________________________________________________________ -->
3096<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3097 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3098</div>
3099<div class="doc_text">
3100
3101<h5>Syntax:</h5>
3102<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3103 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3104</pre>
3105
3106<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3107<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3108<tt>ty2</tt> without changing any bits.</p>
3109
3110<h5>Arguments:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3111<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3112a first class value, and a type to cast it to, which must also be a <a
3113 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
3114and the destination type, <tt>ty2</tt>, must be identical.</p>
3115
3116<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3117<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3118<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3119this conversion. The conversion is done as if the <tt>value</tt> had been
3120stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3121converted to other pointer types with this instruction. To convert pointers to
3122other types, use the <a href="#i_inttoptr">inttoptr</a> or
3123<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3124
3125<h5>Example:</h5>
3126<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3127 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
3128 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
3129 %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3130</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3131</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3132
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3133<!-- ======================================================================= -->
3134<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3135<div class="doc_text">
3136<p>The instructions in this category are the "miscellaneous"
3137instructions, which defy better classification.</p>
3138</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3139
3140<!-- _______________________________________________________________________ -->
3141<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3142</div>
3143<div class="doc_text">
3144<h5>Syntax:</h5>
3145<pre> &lt;result&gt; = icmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
3146</pre>
3147<h5>Overview:</h5>
3148<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
3149of its two integer operands.</p>
3150<h5>Arguments:</h5>
3151<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
3152the condition code which indicates the kind of comparison to perform. It is not
3153a value, just a keyword. The possibilities for the condition code are:
3154<ol>
3155 <li><tt>eq</tt>: equal</li>
3156 <li><tt>ne</tt>: not equal </li>
3157 <li><tt>ugt</tt>: unsigned greater than</li>
3158 <li><tt>uge</tt>: unsigned greater or equal</li>
3159 <li><tt>ult</tt>: unsigned less than</li>
3160 <li><tt>ule</tt>: unsigned less or equal</li>
3161 <li><tt>sgt</tt>: signed greater than</li>
3162 <li><tt>sge</tt>: signed greater or equal</li>
3163 <li><tt>slt</tt>: signed less than</li>
3164 <li><tt>sle</tt>: signed less or equal</li>
3165</ol>
3166<p>The remaining two arguments must be of <a href="#t_integral">integral</a>,
3167<a href="#t_pointer">pointer</a> or a <a href="#t_packed">packed</a> integral
3168type. They must have identical types.</p>
3169<h5>Semantics:</h5>
3170<p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3171the condition code given as <tt>cond</tt>. The comparison performed always
3172yields a <a href="#t_bool">bool</a> result, as follows:
3173<ol>
3174 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3175 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3176 </li>
3177 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3178 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3179 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3180 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3181 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3182 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3183 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3184 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3185 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3186 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3187 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3188 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3189 <li><tt>sge</tt>: interprets the operands as signed values and yields
3190 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3191 <li><tt>slt</tt>: interprets the operands as signed values and yields
3192 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3193 <li><tt>sle</tt>: interprets the operands as signed values and yields
3194 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3195 </li>
3196</ol>
3197<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
3198values are treated as integers and then compared.</p>
3199<p>If the operands are <a href="#t_packed">packed</a> typed, the elements of
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3200the vector are compared in turn and the predicate must hold for all
3201elements.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3202
3203<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3204<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3205 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3206 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3207 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3208 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3209 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3210</pre>
3211</div>
3212
3213<!-- _______________________________________________________________________ -->
3214<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3215</div>
3216<div class="doc_text">
3217<h5>Syntax:</h5>
3218<pre> &lt;result&gt; = fcmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
3219</pre>
3220<h5>Overview:</h5>
3221<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3222of its floating point operands.</p>
3223<h5>Arguments:</h5>
3224<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
3225the condition code which indicates the kind of comparison to perform. It is not
3226a value, just a keyword. The possibilities for the condition code are:
3227<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3228 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3229 <li><tt>oeq</tt>: ordered and equal</li>
3230 <li><tt>ogt</tt>: ordered and greater than </li>
3231 <li><tt>oge</tt>: ordered and greater than or equal</li>
3232 <li><tt>olt</tt>: ordered and less than </li>
3233 <li><tt>ole</tt>: ordered and less than or equal</li>
3234 <li><tt>one</tt>: ordered and not equal</li>
3235 <li><tt>ord</tt>: ordered (no nans)</li>
3236 <li><tt>ueq</tt>: unordered or equal</li>
3237 <li><tt>ugt</tt>: unordered or greater than </li>
3238 <li><tt>uge</tt>: unordered or greater than or equal</li>
3239 <li><tt>ult</tt>: unordered or less than </li>
3240 <li><tt>ule</tt>: unordered or less than or equal</li>
3241 <li><tt>une</tt>: unordered or not equal</li>
3242 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3243 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3244</ol>
Reid Spencer93a49852006-12-06 07:08:07 +0000[diff] [blame]3245<p>In the preceding, <i>ordered</i> means that neither operand is a QNAN while
3246<i>unordered</i> means that either operand may be a QNAN.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3247<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be of
3248<a href="#t_floating">floating point</a>, or a <a href="#t_packed">packed</a>
3249floating point type. They must have identical types.</p>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3250<p>In the foregoing, <i>ordered</i> means that neither operand is a QNAN and
3251<i>unordered</i> means that either operand is a QNAN.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3252<h5>Semantics:</h5>
3253<p>The '<tt>fcmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3254the condition code given as <tt>cond</tt>. The comparison performed always
3255yields a <a href="#t_bool">bool</a> result, as follows:
3256<ol>
3257 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3258 <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3259 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3260 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3261 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3262 <li><tt>oge</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3263 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3264 <li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3265 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3266 <li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3267 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3268 <li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3269 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3270 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3271 <li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3272 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3273 <li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3274 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3275 <li><tt>uge</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3276 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3277 <li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3278 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3279 <li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3280 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3281 <li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3282 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3283 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3284 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3285</ol>
3286<p>If the operands are <a href="#t_packed">packed</a> typed, the elements of
3287the vector are compared in turn and the predicate must hold for all elements.
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3288</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3289
3290<h5>Example:</h5>
3291<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3292 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3293 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3294 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3295</pre>
3296</div>
3297
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3298<!-- _______________________________________________________________________ -->
3299<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
3300Instruction</a> </div>
3301<div class="doc_text">
3302<h5>Syntax:</h5>
3303<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
3304<h5>Overview:</h5>
3305<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
3306the SSA graph representing the function.</p>
3307<h5>Arguments:</h5>
3308<p>The type of the incoming values are specified with the first type
3309field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
3310as arguments, with one pair for each predecessor basic block of the
3311current block. Only values of <a href="#t_firstclass">first class</a>
3312type may be used as the value arguments to the PHI node. Only labels
3313may be used as the label arguments.</p>
3314<p>There must be no non-phi instructions between the start of a basic
3315block and the PHI instructions: i.e. PHI instructions must be first in
3316a basic block.</p>
3317<h5>Semantics:</h5>
3318<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the
3319value specified by the parameter, depending on which basic block we
3320came from in the last <a href="#terminators">terminator</a> instruction.</p>
3321<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3322<pre>Loop: ; Infinite loop that counts from 0 on up...<br> %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]<br> %nextindvar = add i32 %indvar, 1<br> br label %Loop<br></pre>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3323</div>
3324
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3325<!-- _______________________________________________________________________ -->
3326<div class="doc_subsubsection">
3327 <a name="i_select">'<tt>select</tt>' Instruction</a>
3328</div>
3329
3330<div class="doc_text">
3331
3332<h5>Syntax:</h5>
3333
3334<pre>
3335 &lt;result&gt; = select bool &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
3336</pre>
3337
3338<h5>Overview:</h5>
3339
3340<p>
3341The '<tt>select</tt>' instruction is used to choose one value based on a
3342condition, without branching.
3343</p>
3344
3345
3346<h5>Arguments:</h5>
3347
3348<p>
3349The '<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.
3350</p>
3351
3352<h5>Semantics:</h5>
3353
3354<p>
3355If the boolean condition evaluates to true, the instruction returns the first
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3356value argument; otherwise, it returns the second value argument.
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3357</p>
3358
3359<h5>Example:</h5>
3360
3361<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3362 %X = select bool true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3363</pre>
3364</div>
3365
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]3366
3367<!-- _______________________________________________________________________ -->
3368<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3369 <a name="i_call">'<tt>call</tt>' Instruction</a>
3370</div>
3371
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3372<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3373
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3374<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3375<pre>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3376 &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]3377</pre>
3378
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3379<h5>Overview:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3380
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3381<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3382
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3383<h5>Arguments:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3384
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3385<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3386
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3387<ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3388 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3389 <p>The optional "tail" marker indicates whether the callee function accesses
3390 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3391 function call is eligible for tail call optimization. Note that calls may
3392 be marked "tail" even if they do not occur before a <a
3393 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3394 </li>
3395 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3396 <p>The optional "cconv" marker indicates which <a href="callingconv">calling
3397 convention</a> the call should use. If none is specified, the call defaults
3398 to using C calling conventions.
3399 </li>
3400 <li>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3401 <p>'<tt>ty</tt>': shall be the signature of the pointer to function value
3402 being invoked. The argument types must match the types implied by this
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3403 signature. This type can be omitted if the function is not varargs and
3404 if the function type does not return a pointer to a function.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3405 </li>
3406 <li>
3407 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
3408 be invoked. In most cases, this is a direct function invocation, but
3409 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3410 to function value.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3411 </li>
3412 <li>
3413 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencera7e302a2005-05-01 22:22:57 +0000[diff] [blame]3414 function signature argument types. All arguments must be of
3415 <a href="#t_firstclass">first class</a> type. If the function signature
3416 indicates the function accepts a variable number of arguments, the extra
3417 arguments can be specified.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3418 </li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3419</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3420
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3421<h5>Semantics:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3422
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3423<p>The '<tt>call</tt>' instruction is used to cause control flow to
3424transfer to a specified function, with its incoming arguments bound to
3425the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
3426instruction in the called function, control flow continues with the
3427instruction after the function call, and the return value of the
3428function is bound to the result argument. This is a simpler case of
3429the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3430
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3431<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3432
3433<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3434 %retval = call i32 %test(i32 %argc)
3435 call i32(i8 *, ...) *%printf(i8 * %msg, i32 12, i8 42);
3436 %X = tail call i32 %foo()
3437 %Y = tail call <a href="#callingconv">fastcc</a> i32 %foo()
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3438</pre>
3439
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3440</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3441
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3442<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3443<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3444 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3445</div>
3446
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3447<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3448
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3449<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3450
3451<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3452 &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]3453</pre>
3454
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3455<h5>Overview:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3456
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3457<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3458the "variable argument" area of a function call. It is used to implement the
3459<tt>va_arg</tt> macro in C.</p>
3460
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3461<h5>Arguments:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3462
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3463<p>This instruction takes a <tt>va_list*</tt> value and the type of
3464the argument. It returns a value of the specified argument type and
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]3465increments the <tt>va_list</tt> to point to the next argument. Again, the
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3466actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3467
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3468<h5>Semantics:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3469
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3470<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
3471type from the specified <tt>va_list</tt> and causes the
3472<tt>va_list</tt> to point to the next argument. For more information,
3473see the variable argument handling <a href="#int_varargs">Intrinsic
3474Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3475
3476<p>It is legal for this instruction to be called in a function which does not
3477take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3478function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3479
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3480<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3481href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3482argument.</p>
3483
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3484<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3485
3486<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
3487
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3488</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3489
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3490<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3491<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
3492<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3493
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3494<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3495
3496<p>LLVM supports the notion of an "intrinsic function". These functions have
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3497well known names and semantics and are required to follow certain
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3498restrictions. Overall, these instructions represent an extension mechanism for
3499the LLVM language that does not require changing all of the transformations in
3500LLVM to add to the language (or the bytecode reader/writer, the parser,
3501etc...).</p>
3502
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3503<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
3504prefix is reserved in LLVM for intrinsic names; thus, functions may not be named
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3505this. Intrinsic functions must always be external functions: you cannot define
3506the body of intrinsic functions. Intrinsic functions may only be used in call
3507or invoke instructions: it is illegal to take the address of an intrinsic
3508function. Additionally, because intrinsic functions are part of the LLVM
3509language, it is required that they all be documented here if any are added.</p>
3510
3511
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3512<p>To learn how to add an intrinsic function, please see the <a
Chris Lattner590cff32005-05-11 03:35:57 +0000[diff] [blame]3513href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3514</p>
3515
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3516</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3517
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3518<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3519<div class="doc_subsection">
3520 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
3521</div>
3522
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3523<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3524
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3525<p>Variable argument support is defined in LLVM with the <a
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3526 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3527intrinsic functions. These functions are related to the similarly
3528named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3529
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3530<p>All of these functions operate on arguments that use a
3531target-specific value type "<tt>va_list</tt>". The LLVM assembly
3532language reference manual does not define what this type is, so all
3533transformations should be prepared to handle intrinsics with any type
3534used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3535
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]3536<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]3537instruction and the variable argument handling intrinsic functions are
3538used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3539
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3540<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3541define i32 %test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3542 ; Initialize variable argument processing
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3543 %ap = alloca i8 *
3544 call void %<a href="#i_va_start">llvm.va_start</a>(i8 ** %ap)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3545
3546 ; Read a single integer argument
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3547 %tmp = va_arg i8 ** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3548
3549 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3550 %aq = alloca i8 *
3551 call void %<a href="#i_va_copy">llvm.va_copy</a>(i8 ** %aq, i8 ** %ap)
3552 call void %<a href="#i_va_end">llvm.va_end</a>(i8 ** %aq)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3553
3554 ; Stop processing of arguments.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3555 call void %<a href="#i_va_end">llvm.va_end</a>(i8 ** %ap)
3556 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3557}
3558</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3559</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3560
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3561<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3562<div class="doc_subsubsection">
3563 <a name="i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
3564</div>
3565
3566
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3567<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3568<h5>Syntax:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3569<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]3570<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3571<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
3572<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
3573href="#i_va_arg">va_arg</a></tt>.</p>
3574
3575<h5>Arguments:</h5>
3576
3577<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
3578
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3579<h5>Semantics:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3580
3581<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
3582macro available in C. In a target-dependent way, it initializes the
3583<tt>va_list</tt> element the argument points to, so that the next call to
3584<tt>va_arg</tt> will produce the first variable argument passed to the function.
3585Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
3586last argument of the function, the compiler can figure that out.</p>
3587
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3588</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3589
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3590<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3591<div class="doc_subsubsection">
3592 <a name="i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
3593</div>
3594
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3595<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3596<h5>Syntax:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3597<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]3598<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3599<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>&lt;arglist&gt;</tt>
3600which has been initialized previously with <tt><a href="#i_va_start">llvm.va_start</a></tt>
3601or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3602<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3603<p>The argument is a <tt>va_list</tt> to destroy.</p>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3604<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3605<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]3606macro available in C. In a target-dependent way, it destroys the <tt>va_list</tt>.
3607Calls to <a href="#i_va_start"><tt>llvm.va_start</tt></a> and <a
3608 href="#i_va_copy"><tt>llvm.va_copy</tt></a> must be matched exactly
3609with calls to <tt>llvm.va_end</tt>.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3610</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3611
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3612<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3613<div class="doc_subsubsection">
3614 <a name="i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
3615</div>
3616
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3617<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3618
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3619<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3620
3621<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3622 declare void %llvm.va_copy(&lt;va_list&gt;* &lt;destarglist&gt;,
Andrew Lenharthd0a4c622005-06-22 20:38:11 +0000[diff] [blame]3623 &lt;va_list&gt;* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3624</pre>
3625
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3626<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3627
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3628<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position from
3629the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3630
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3631<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3632
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3633<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]3634The 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]3635
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3636
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3637<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3638
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3639<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt> macro
3640available in C. In a target-dependent way, it copies the source
3641<tt>va_list</tt> element into the destination list. This intrinsic is necessary
3642because 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]3643arbitrarily complex and require memory allocation, for example.</p>
3644
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3645</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3646
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3647<!-- ======================================================================= -->
3648<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3649 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
3650</div>
3651
3652<div class="doc_text">
3653
3654<p>
3655LLVM support for <a href="GarbageCollection.html">Accurate Garbage
3656Collection</a> requires the implementation and generation of these intrinsics.
3657These intrinsics allow identification of <a href="#i_gcroot">GC roots on the
3658stack</a>, as well as garbage collector implementations that require <a
3659href="#i_gcread">read</a> and <a href="#i_gcwrite">write</a> barriers.
3660Front-ends for type-safe garbage collected languages should generate these
3661intrinsics to make use of the LLVM garbage collectors. For more details, see <a
3662href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
3663</p>
3664</div>
3665
3666<!-- _______________________________________________________________________ -->
3667<div class="doc_subsubsection">
3668 <a name="i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
3669</div>
3670
3671<div class="doc_text">
3672
3673<h5>Syntax:</h5>
3674
3675<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]3676 declare void %llvm.gcroot(&lt;ty&gt;** %ptrloc, &lt;ty2&gt;* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3677</pre>
3678
3679<h5>Overview:</h5>
3680
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]3681<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]3682the code generator, and allows some metadata to be associated with it.</p>
3683
3684<h5>Arguments:</h5>
3685
3686<p>The first argument specifies the address of a stack object that contains the
3687root pointer. The second pointer (which must be either a constant or a global
3688value address) contains the meta-data to be associated with the root.</p>
3689
3690<h5>Semantics:</h5>
3691
3692<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
3693location. At compile-time, the code generator generates information to allow
3694the runtime to find the pointer at GC safe points.
3695</p>
3696
3697</div>
3698
3699
3700<!-- _______________________________________________________________________ -->
3701<div class="doc_subsubsection">
3702 <a name="i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
3703</div>
3704
3705<div class="doc_text">
3706
3707<h5>Syntax:</h5>
3708
3709<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3710 declare i8 * %llvm.gcread(i8 * %ObjPtr, i8 ** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3711</pre>
3712
3713<h5>Overview:</h5>
3714
3715<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
3716locations, allowing garbage collector implementations that require read
3717barriers.</p>
3718
3719<h5>Arguments:</h5>
3720
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3721<p>The second argument is the address to read from, which should be an address
3722allocated from the garbage collector. The first object is a pointer to the
3723start of the referenced object, if needed by the language runtime (otherwise
3724null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3725
3726<h5>Semantics:</h5>
3727
3728<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
3729instruction, but may be replaced with substantially more complex code by the
3730garbage collector runtime, as needed.</p>
3731
3732</div>
3733
3734
3735<!-- _______________________________________________________________________ -->
3736<div class="doc_subsubsection">
3737 <a name="i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
3738</div>
3739
3740<div class="doc_text">
3741
3742<h5>Syntax:</h5>
3743
3744<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3745 declare void %llvm.gcwrite(i8 * %P1, i8 * %Obj, i8 ** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3746</pre>
3747
3748<h5>Overview:</h5>
3749
3750<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
3751locations, allowing garbage collector implementations that require write
3752barriers (such as generational or reference counting collectors).</p>
3753
3754<h5>Arguments:</h5>
3755
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3756<p>The first argument is the reference to store, the second is the start of the
3757object to store it to, and the third is the address of the field of Obj to
3758store to. If the runtime does not require a pointer to the object, Obj may be
3759null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3760
3761<h5>Semantics:</h5>
3762
3763<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
3764instruction, but may be replaced with substantially more complex code by the
3765garbage collector runtime, as needed.</p>
3766
3767</div>
3768
3769
3770
3771<!-- ======================================================================= -->
3772<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3773 <a name="int_codegen">Code Generator Intrinsics</a>
3774</div>
3775
3776<div class="doc_text">
3777<p>
3778These intrinsics are provided by LLVM to expose special features that may only
3779be implemented with code generator support.
3780</p>
3781
3782</div>
3783
3784<!-- _______________________________________________________________________ -->
3785<div class="doc_subsubsection">
3786 <a name="i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
3787</div>
3788
3789<div class="doc_text">
3790
3791<h5>Syntax:</h5>
3792<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3793 declare i8 *%llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3794</pre>
3795
3796<h5>Overview:</h5>
3797
3798<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]3799The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
3800target-specific value indicating the return address of the current function
3801or one of its callers.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3802</p>
3803
3804<h5>Arguments:</h5>
3805
3806<p>
3807The argument to this intrinsic indicates which function to return the address
3808for. Zero indicates the calling function, one indicates its caller, etc. The
3809argument is <b>required</b> to be a constant integer value.
3810</p>
3811
3812<h5>Semantics:</h5>
3813
3814<p>
3815The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
3816the return address of the specified call frame, or zero if it cannot be
3817identified. The value returned by this intrinsic is likely to be incorrect or 0
3818for arguments other than zero, so it should only be used for debugging purposes.
3819</p>
3820
3821<p>
3822Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]3823aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3824source-language caller.
3825</p>
3826</div>
3827
3828
3829<!-- _______________________________________________________________________ -->
3830<div class="doc_subsubsection">
3831 <a name="i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
3832</div>
3833
3834<div class="doc_text">
3835
3836<h5>Syntax:</h5>
3837<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3838 declare i8 *%llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3839</pre>
3840
3841<h5>Overview:</h5>
3842
3843<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]3844The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
3845target-specific frame pointer value for the specified stack frame.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3846</p>
3847
3848<h5>Arguments:</h5>
3849
3850<p>
3851The argument to this intrinsic indicates which function to return the frame
3852pointer for. Zero indicates the calling function, one indicates its caller,
3853etc. The argument is <b>required</b> to be a constant integer value.
3854</p>
3855
3856<h5>Semantics:</h5>
3857
3858<p>
3859The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
3860the frame address of the specified call frame, or zero if it cannot be
3861identified. The value returned by this intrinsic is likely to be incorrect or 0
3862for arguments other than zero, so it should only be used for debugging purposes.
3863</p>
3864
3865<p>
3866Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]3867aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3868source-language caller.
3869</p>
3870</div>
3871
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3872<!-- _______________________________________________________________________ -->
3873<div class="doc_subsubsection">
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]3874 <a name="i_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
3875</div>
3876
3877<div class="doc_text">
3878
3879<h5>Syntax:</h5>
3880<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3881 declare i8 *%llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]3882</pre>
3883
3884<h5>Overview:</h5>
3885
3886<p>
3887The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
3888the function stack, for use with <a href="#i_stackrestore">
3889<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
3890features like scoped automatic variable sized arrays in C99.
3891</p>
3892
3893<h5>Semantics:</h5>
3894
3895<p>
3896This intrinsic returns a opaque pointer value that can be passed to <a
3897href="#i_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
3898<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
3899<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
3900state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
3901practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
3902that were allocated after the <tt>llvm.stacksave</tt> was executed.
3903</p>
3904
3905</div>
3906
3907<!-- _______________________________________________________________________ -->
3908<div class="doc_subsubsection">
3909 <a name="i_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
3910</div>
3911
3912<div class="doc_text">
3913
3914<h5>Syntax:</h5>
3915<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3916 declare void %llvm.stackrestore(i8 * %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]3917</pre>
3918
3919<h5>Overview:</h5>
3920
3921<p>
3922The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
3923the function stack to the state it was in when the corresponding <a
3924href="#llvm.stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
3925useful for implementing language features like scoped automatic variable sized
3926arrays in C99.
3927</p>
3928
3929<h5>Semantics:</h5>
3930
3931<p>
3932See the description for <a href="#i_stacksave"><tt>llvm.stacksave</tt></a>.
3933</p>
3934
3935</div>
3936
3937
3938<!-- _______________________________________________________________________ -->
3939<div class="doc_subsubsection">
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3940 <a name="i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
3941</div>
3942
3943<div class="doc_text">
3944
3945<h5>Syntax:</h5>
3946<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3947 declare void %llvm.prefetch(i8 * &lt;address&gt;,
3948 i32 &lt;rw&gt;, i32 &lt;locality&gt;)
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3949</pre>
3950
3951<h5>Overview:</h5>
3952
3953
3954<p>
3955The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3956a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
3957no
3958effect on the behavior of the program but can change its performance
Chris Lattner2a615362005-02-28 19:47:14 +0000[diff] [blame]3959characteristics.
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3960</p>
3961
3962<h5>Arguments:</h5>
3963
3964<p>
3965<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
3966determining if the fetch should be for a read (0) or write (1), and
3967<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattneraeffb4a2005-03-07 20:31:38 +0000[diff] [blame]3968locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3969<tt>locality</tt> arguments must be constant integers.
3970</p>
3971
3972<h5>Semantics:</h5>
3973
3974<p>
3975This intrinsic does not modify the behavior of the program. In particular,
3976prefetches cannot trap and do not produce a value. On targets that support this
3977intrinsic, the prefetch can provide hints to the processor cache for better
3978performance.
3979</p>
3980
3981</div>
3982
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]3983<!-- _______________________________________________________________________ -->
3984<div class="doc_subsubsection">
3985 <a name="i_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
3986</div>
3987
3988<div class="doc_text">
3989
3990<h5>Syntax:</h5>
3991<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3992 declare void %llvm.pcmarker( i32 &lt;id&gt; )
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]3993</pre>
3994
3995<h5>Overview:</h5>
3996
3997
3998<p>
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3999The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
4000(PC) in a region of
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4001code to simulators and other tools. The method is target specific, but it is
4002expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]4003The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnerd07c3f42005-11-15 06:07:55 +0000[diff] [blame]4004after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb3e7afd2006-03-24 07:16:10 +0000[diff] [blame]4005optimizations. The intended use is to be inserted after optimizations to allow
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4006correlations of simulation runs.
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4007</p>
4008
4009<h5>Arguments:</h5>
4010
4011<p>
4012<tt>id</tt> is a numerical id identifying the marker.
4013</p>
4014
4015<h5>Semantics:</h5>
4016
4017<p>
4018This intrinsic does not modify the behavior of the program. Backends that do not
4019support this intrinisic may ignore it.
4020</p>
4021
4022</div>
4023
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4024<!-- _______________________________________________________________________ -->
4025<div class="doc_subsubsection">
4026 <a name="i_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
4027</div>
4028
4029<div class="doc_text">
4030
4031<h5>Syntax:</h5>
4032<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4033 declare i64 %llvm.readcyclecounter( )
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4034</pre>
4035
4036<h5>Overview:</h5>
4037
4038
4039<p>
4040The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
4041counter register (or similar low latency, high accuracy clocks) on those targets
4042that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
4043As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
4044should only be used for small timings.
4045</p>
4046
4047<h5>Semantics:</h5>
4048
4049<p>
4050When directly supported, reading the cycle counter should not modify any memory.
4051Implementations are allowed to either return a application specific value or a
4052system wide value. On backends without support, this is lowered to a constant 0.
4053</p>
4054
4055</div>
4056
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4057<!-- ======================================================================= -->
4058<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4059 <a name="int_libc">Standard C Library Intrinsics</a>
4060</div>
4061
4062<div class="doc_text">
4063<p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4064LLVM provides intrinsics for a few important standard C library functions.
4065These intrinsics allow source-language front-ends to pass information about the
4066alignment of the pointer arguments to the code generator, providing opportunity
4067for more efficient code generation.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4068</p>
4069
4070</div>
4071
4072<!-- _______________________________________________________________________ -->
4073<div class="doc_subsubsection">
4074 <a name="i_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
4075</div>
4076
4077<div class="doc_text">
4078
4079<h5>Syntax:</h5>
4080<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4081 declare void %llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4082 i32 &lt;len&gt;, i32 &lt;align&gt;)
4083 declare void %llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4084 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4085</pre>
4086
4087<h5>Overview:</h5>
4088
4089<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4090The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4091location to the destination location.
4092</p>
4093
4094<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4095Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4096intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4097</p>
4098
4099<h5>Arguments:</h5>
4100
4101<p>
4102The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4103the source. The third argument is an integer argument
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4104specifying the number of bytes to copy, and the fourth argument is the alignment
4105of the source and destination locations.
4106</p>
4107
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4108<p>
4109If 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]4110the caller guarantees that both the source and destination pointers are aligned
4111to that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4112</p>
4113
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4114<h5>Semantics:</h5>
4115
4116<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4117The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4118location to the destination location, which are not allowed to overlap. It
4119copies "len" bytes of memory over. If the argument is known to be aligned to
4120some boundary, this can be specified as the fourth argument, otherwise it should
4121be set to 0 or 1.
4122</p>
4123</div>
4124
4125
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4126<!-- _______________________________________________________________________ -->
4127<div class="doc_subsubsection">
4128 <a name="i_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
4129</div>
4130
4131<div class="doc_text">
4132
4133<h5>Syntax:</h5>
4134<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4135 declare void %llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4136 i32 &lt;len&gt;, i32 &lt;align&gt;)
4137 declare void %llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4138 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4139</pre>
4140
4141<h5>Overview:</h5>
4142
4143<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4144The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
4145location to the destination location. It is similar to the
4146'<tt>llvm.memcmp</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4147</p>
4148
4149<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4150Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
4151intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4152</p>
4153
4154<h5>Arguments:</h5>
4155
4156<p>
4157The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4158the source. The third argument is an integer argument
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4159specifying the number of bytes to copy, and the fourth argument is the alignment
4160of the source and destination locations.
4161</p>
4162
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4163<p>
4164If 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]4165the caller guarantees that the source and destination pointers are aligned to
4166that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4167</p>
4168
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4169<h5>Semantics:</h5>
4170
4171<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4172The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4173location to the destination location, which may overlap. It
4174copies "len" bytes of memory over. If the argument is known to be aligned to
4175some boundary, this can be specified as the fourth argument, otherwise it should
4176be set to 0 or 1.
4177</p>
4178</div>
4179
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4180
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4181<!-- _______________________________________________________________________ -->
4182<div class="doc_subsubsection">
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4183 <a name="i_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4184</div>
4185
4186<div class="doc_text">
4187
4188<h5>Syntax:</h5>
4189<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4190 declare void %llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
4191 i32 &lt;len&gt;, i32 &lt;align&gt;)
4192 declare void %llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
4193 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4194</pre>
4195
4196<h5>Overview:</h5>
4197
4198<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4199The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4200byte value.
4201</p>
4202
4203<p>
4204Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
4205does not return a value, and takes an extra alignment argument.
4206</p>
4207
4208<h5>Arguments:</h5>
4209
4210<p>
4211The first argument is a pointer to the destination to fill, the second is the
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4212byte value to fill it with, the third argument is an integer
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4213argument specifying the number of bytes to fill, and the fourth argument is the
4214known alignment of destination location.
4215</p>
4216
4217<p>
4218If 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]4219the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4220</p>
4221
4222<h5>Semantics:</h5>
4223
4224<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4225The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
4226the
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4227destination location. If the argument is known to be aligned to some boundary,
4228this can be specified as the fourth argument, otherwise it should be set to 0 or
42291.
4230</p>
4231</div>
4232
4233
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4234<!-- _______________________________________________________________________ -->
4235<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4236 <a name="i_isunordered">'<tt>llvm.isunordered.*</tt>' Intrinsic</a>
Alkis Evlogimenos26bbe932004-06-13 01:16:15 +0000[diff] [blame]4237</div>
4238
4239<div class="doc_text">
4240
4241<h5>Syntax:</h5>
4242<pre>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4243 declare bool %llvm.isunordered.f32(float Val1, float Val2)
4244 declare bool %llvm.isunordered.f64(double Val1, double Val2)
Alkis Evlogimenos26bbe932004-06-13 01:16:15 +0000[diff] [blame]4245</pre>
4246
4247<h5>Overview:</h5>
4248
4249<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4250The '<tt>llvm.isunordered</tt>' intrinsics return true if either or both of the
Alkis Evlogimenos26bbe932004-06-13 01:16:15 +0000[diff] [blame]4251specified floating point values is a NAN.
4252</p>
4253
4254<h5>Arguments:</h5>
4255
4256<p>
4257The arguments are floating point numbers of the same type.
4258</p>
4259
4260<h5>Semantics:</h5>
4261
4262<p>
4263If either or both of the arguments is a SNAN or QNAN, it returns true, otherwise
4264false.
4265</p>
4266</div>
4267
4268
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4269<!-- _______________________________________________________________________ -->
4270<div class="doc_subsubsection">
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4271 <a name="i_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4272</div>
4273
4274<div class="doc_text">
4275
4276<h5>Syntax:</h5>
4277<pre>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4278 declare float %llvm.sqrt.f32(float %Val)
4279 declare double %llvm.sqrt.f64(double %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4280</pre>
4281
4282<h5>Overview:</h5>
4283
4284<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4285The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4286returning the same value as the libm '<tt>sqrt</tt>' function would. Unlike
4287<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
4288negative numbers (which allows for better optimization).
4289</p>
4290
4291<h5>Arguments:</h5>
4292
4293<p>
4294The argument and return value are floating point numbers of the same type.
4295</p>
4296
4297<h5>Semantics:</h5>
4298
4299<p>
4300This function returns the sqrt of the specified operand if it is a positive
4301floating point number.
4302</p>
4303</div>
4304
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4305<!-- _______________________________________________________________________ -->
4306<div class="doc_subsubsection">
4307 <a name="i_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
4308</div>
4309
4310<div class="doc_text">
4311
4312<h5>Syntax:</h5>
4313<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4314 declare float %llvm.powi.f32(float %Val, i32 %power)
4315 declare double %llvm.powi.f64(double %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4316</pre>
4317
4318<h5>Overview:</h5>
4319
4320<p>
4321The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
4322specified (positive or negative) power. The order of evaluation of
4323multiplications is not defined.
4324</p>
4325
4326<h5>Arguments:</h5>
4327
4328<p>
4329The second argument is an integer power, and the first is a value to raise to
4330that power.
4331</p>
4332
4333<h5>Semantics:</h5>
4334
4335<p>
4336This function returns the first value raised to the second power with an
4337unspecified sequence of rounding operations.</p>
4338</div>
4339
4340
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4341<!-- ======================================================================= -->
4342<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4343 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4344</div>
4345
4346<div class="doc_text">
4347<p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4348LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4349These allow efficient code generation for some algorithms.
4350</p>
4351
4352</div>
4353
4354<!-- _______________________________________________________________________ -->
4355<div class="doc_subsubsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4356 <a name="i_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
4357</div>
4358
4359<div class="doc_text">
4360
4361<h5>Syntax:</h5>
4362<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4363 declare i16 %llvm.bswap.i16(i16 &lt;id&gt;)
4364 declare i32 %llvm.bswap.i32(i32 &lt;id&gt;)
4365 declare i64 %llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4366</pre>
4367
4368<h5>Overview:</h5>
4369
4370<p>
4371The '<tt>llvm.bwsap</tt>' family of intrinsics is used to byteswap a 16, 32 or
437264 bit quantity. These are useful for performing operations on data that is not
4373in the target's native byte order.
4374</p>
4375
4376<h5>Semantics:</h5>
4377
4378<p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4379The <tt>llvm.bswap.16</tt> intrinsic returns an i16 value that has the high
4380and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
4381intrinsic returns an i32 value that has the four bytes of the input i32
4382swapped, so that if the input bytes are numbered 0, 1, 2, 3 then the returned
4383i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i64</tt>
4384intrinsic extends this concept to 64 bits.
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4385</p>
4386
4387</div>
4388
4389<!-- _______________________________________________________________________ -->
4390<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4391 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4392</div>
4393
4394<div class="doc_text">
4395
4396<h5>Syntax:</h5>
4397<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4398 declare i8 %llvm.ctpop.i8 (i8 &lt;src&gt;)
4399 declare i16 %llvm.ctpop.i16(i16 &lt;src&gt;)
4400 declare i32 %llvm.ctpop.i32(i32 &lt;src&gt;)
4401 declare i64 %llvm.ctpop.i64(i64 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4402</pre>
4403
4404<h5>Overview:</h5>
4405
4406<p>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4407The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
4408value.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4409</p>
4410
4411<h5>Arguments:</h5>
4412
4413<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]4414The only argument is the value to be counted. The argument may be of any
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4415unsigned integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4416</p>
4417
4418<h5>Semantics:</h5>
4419
4420<p>
4421The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
4422</p>
4423</div>
4424
4425<!-- _______________________________________________________________________ -->
4426<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]4427 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4428</div>
4429
4430<div class="doc_text">
4431
4432<h5>Syntax:</h5>
4433<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4434 declare i8 %llvm.ctlz.i8 (i8 &lt;src&gt;)
4435 declare i16 %llvm.ctlz.i16(i16 &lt;src&gt;)
4436 declare i32 %llvm.ctlz.i32(i32 &lt;src&gt;)
4437 declare i64 %llvm.ctlz.i64(i64 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4438</pre>
4439
4440<h5>Overview:</h5>
4441
4442<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4443The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
4444leading zeros in a variable.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4445</p>
4446
4447<h5>Arguments:</h5>
4448
4449<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]4450The only argument is the value to be counted. The argument may be of any
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4451unsigned integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4452</p>
4453
4454<h5>Semantics:</h5>
4455
4456<p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4457The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
4458in a variable. If the src == 0 then the result is the size in bits of the type
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4459of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4460</p>
4461</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4462
4463
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4464
4465<!-- _______________________________________________________________________ -->
4466<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]4467 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4468</div>
4469
4470<div class="doc_text">
4471
4472<h5>Syntax:</h5>
4473<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4474 declare i8 %llvm.cttz.i8 (i8 &lt;src&gt;)
4475 declare i16 %llvm.cttz.i16(i16 &lt;src&gt;)
4476 declare i32 %llvm.cttz.i32(i32 &lt;src&gt;)
4477 declare i64 %llvm.cttz.i64(i64 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4478</pre>
4479
4480<h5>Overview:</h5>
4481
4482<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4483The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
4484trailing zeros.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4485</p>
4486
4487<h5>Arguments:</h5>
4488
4489<p>
4490The only argument is the value to be counted. The argument may be of any
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4491unsigned integer type. The return type must match the argument type.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4492</p>
4493
4494<h5>Semantics:</h5>
4495
4496<p>
4497The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
4498in a variable. If the src == 0 then the result is the size in bits of the type
4499of src. For example, <tt>llvm.cttz(2) = 1</tt>.
4500</p>
4501</div>
4502
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4503<!-- ======================================================================= -->
4504<div class="doc_subsection">
4505 <a name="int_debugger">Debugger Intrinsics</a>
4506</div>
4507
4508<div class="doc_text">
4509<p>
4510The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
4511are described in the <a
4512href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
4513Debugging</a> document.
4514</p>
4515</div>
4516
4517
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4518<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4519<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]4520<address>
4521 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
4522 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
4523 <a href="http://validator.w3.org/check/referer"><img
4524 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!" /></a>
4525
4526 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]4527 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]4528 Last modified: $Date$
4529</address>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4530</body>
4531</html>