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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / c28d2bc476cd3a75612596718cef9bed997e8fc0 / . / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
Reid Spencer3921c742004-08-26 20:44:00 +0000[diff] [blame]6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
8 <meta name="description"
9 content="LLVM Assembly Language Reference Manual.">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]14
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]15<div class="doc_title"> LLVM Language Reference Manual </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a></li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]24 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]25 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]26 <li><a href="#functionstructure">Functions</a></li>
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 Spencerc28d2bc2006-12-31 21:30:18 +0000[diff] [blame^]523 prototype and implemented declaration of the function (as does normal C).
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]524 </dd>
525
Chris Lattner5710ce92006-05-19 21:15:36 +0000[diff] [blame]526 <dt><b>"<tt>csretcc</tt>" - The C struct return calling convention</b>:</dt>
527
528 <dd>This calling convention matches the target C calling conventions, except
529 that functions with this convention are required to take a pointer as their
530 first argument, and the return type of the function must be void. This is
531 used for C functions that return aggregates by-value. In this case, the
532 function has been transformed to take a pointer to the struct as the first
533 argument to the function. For targets where the ABI specifies specific
534 behavior for structure-return calls, the calling convention can be used to
535 distinguish between struct return functions and other functions that take a
536 pointer to a struct as the first argument.
537 </dd>
538
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]539 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
540
541 <dd>This calling convention attempts to make calls as fast as possible
542 (e.g. by passing things in registers). This calling convention allows the
543 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner8cdc5bc2005-05-06 23:08:23 +0000[diff] [blame]544 without having to conform to an externally specified ABI. Implementations of
545 this convention should allow arbitrary tail call optimization to be supported.
546 This calling convention does not support varargs and requires the prototype of
547 all callees to exactly match the prototype of the function definition.
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]548 </dd>
549
550 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
551
552 <dd>This calling convention attempts to make code in the caller as efficient
553 as possible under the assumption that the call is not commonly executed. As
554 such, these calls often preserve all registers so that the call does not break
555 any live ranges in the caller side. This calling convention does not support
556 varargs and requires the prototype of all callees to exactly match the
557 prototype of the function definition.
558 </dd>
559
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]560 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]561
562 <dd>Any calling convention may be specified by number, allowing
563 target-specific calling conventions to be used. Target specific calling
564 conventions start at 64.
565 </dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]566</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]567
568<p>More calling conventions can be added/defined on an as-needed basis, to
569support pascal conventions or any other well-known target-independent
570convention.</p>
571
572</div>
573
574<!-- ======================================================================= -->
575<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]576 <a name="globalvars">Global Variables</a>
577</div>
578
579<div class="doc_text">
580
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]581<p>Global variables define regions of memory allocated at compilation time
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]582instead of run-time. Global variables may optionally be initialized, may have
583an explicit section to be placed in, and may
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]584have an optional explicit alignment specified. A
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]585variable may be defined as a global "constant," which indicates that the
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]586contents of the variable will <b>never</b> be modified (enabling better
587optimization, allowing the global data to be placed in the read-only section of
588an executable, etc). Note that variables that need runtime initialization
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]589cannot be marked "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]590
591<p>
592LLVM explicitly allows <em>declarations</em> of global variables to be marked
593constant, even if the final definition of the global is not. This capability
594can be used to enable slightly better optimization of the program, but requires
595the language definition to guarantee that optimizations based on the
596'constantness' are valid for the translation units that do not include the
597definition.
598</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]599
600<p>As SSA values, global variables define pointer values that are in
601scope (i.e. they dominate) all basic blocks in the program. Global
602variables always define a pointer to their "content" type because they
603describe a region of memory, and all memory objects in LLVM are
604accessed through pointers.</p>
605
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]606<p>LLVM allows an explicit section to be specified for globals. If the target
607supports it, it will emit globals to the section specified.</p>
608
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]609<p>An explicit alignment may be specified for a global. If not present, or if
610the alignment is set to zero, the alignment of the global is set by the target
611to whatever it feels convenient. If an explicit alignment is specified, the
612global is forced to have at least that much alignment. All alignments must be
613a power of 2.</p>
614
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]615</div>
616
617
618<!-- ======================================================================= -->
619<div class="doc_subsection">
620 <a name="functionstructure">Functions</a>
621</div>
622
623<div class="doc_text">
624
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]625<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
626an optional <a href="#linkage">linkage type</a>, an optional
627<a href="#callingconv">calling convention</a>, a return type, an optional
628<a href="#paramattrs">parameter attribute</a> for the return type, a function
629name, a (possibly empty) argument list (each with optional
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]630<a href="#paramattrs">parameter attributes</a>), an optional section, an
631optional alignment, an opening curly brace, a list of basic blocks, and a
632closing curly brace. LLVM function declarations
633consist of the "<tt>declare</tt>" keyword, an optional <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]634 href="#callingconv">calling convention</a>, a return type, an optional
635<a href="#paramattrs">parameter attribute</a> for the return type, a function
636name, a possibly empty list of arguments, and an optional alignment.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]637
638<p>A function definition contains a list of basic blocks, forming the CFG for
639the function. Each basic block may optionally start with a label (giving the
640basic block a symbol table entry), contains a list of instructions, and ends
641with a <a href="#terminators">terminator</a> instruction (such as a branch or
642function return).</p>
643
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]644<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]645executed on entrance to the function, and it is not allowed to have predecessor
646basic blocks (i.e. there can not be any branches to the entry block of a
647function). Because the block can have no predecessors, it also cannot have any
648<a href="#i_phi">PHI nodes</a>.</p>
649
650<p>LLVM functions are identified by their name and type signature. Hence, two
651functions with the same name but different parameter lists or return values are
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]652considered different functions, and LLVM will resolve references to each
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]653appropriately.</p>
654
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]655<p>LLVM allows an explicit section to be specified for functions. If the target
656supports it, it will emit functions to the section specified.</p>
657
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]658<p>An explicit alignment may be specified for a function. If not present, or if
659the alignment is set to zero, the alignment of the function is set by the target
660to whatever it feels convenient. If an explicit alignment is specified, the
661function is forced to have at least that much alignment. All alignments must be
662a power of 2.</p>
663
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]664</div>
665
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]666<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]667<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
668<div class="doc_text">
669 <p>The return type and each parameter of a function type may have a set of
670 <i>parameter attributes</i> associated with them. Parameter attributes are
671 used to communicate additional information about the result or parameters of
672 a function. Parameter attributes are considered to be part of the function
673 type so two functions types that differ only by the parameter attributes
674 are different function types.</p>
675
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]676 <p>Parameter attributes consist of an at sign (@) followed by either a single
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]677 keyword or a comma separate list of keywords enclosed in parentheses. For
678 example:<pre>
679 %someFunc = i16 @zext (i8 @(sext) %someParam)
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]680 %someFunc = i16 @zext (i8 @zext %someParam)</pre>
681 Note that the two function types above are unique because the parameter
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]682 has a different attribute (@sext in the first one, @zext in the second).</p>
683
684 <p>Currently, only the following parameter attributes are defined:
685 <dl>
686 <dt><tt>@zext</tt></dt>
687 <dd>This indicates that the parameter should be zero extended just before
688 a call to this function.</dd>
689 <dt><tt>@sext</tt></dt>
690 <dd>This indicates that the parameter should be sign extended just before
691 a call to this function.</dd>
692 </dl></p>
693
694 <p>The current motivation for parameter attributes is to enable the sign and
695 zero extend information necessary for the C calling convention to be passed
696 from the front end to LLVM. The <tt>@zext</tt> and <tt>@sext</tt> attributes
697 are used by the code generator to perform the required extension. However,
698 parameter attributes are an orthogonal feature to calling conventions and
699 may be used for other purposes in the future.</p>
700</div>
701
702<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]703<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]704 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]705</div>
706
707<div class="doc_text">
708<p>
709Modules may contain "module-level inline asm" blocks, which corresponds to the
710GCC "file scope inline asm" blocks. These blocks are internally concatenated by
711LLVM and treated as a single unit, but may be separated in the .ll file if
712desired. The syntax is very simple:
713</p>
714
715<div class="doc_code"><pre>
Chris Lattner52599e12006-01-24 00:37:20 +0000[diff] [blame]716 module asm "inline asm code goes here"
717 module asm "more can go here"
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]718</pre></div>
719
720<p>The strings can contain any character by escaping non-printable characters.
721 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
722 for the number.
723</p>
724
725<p>
726 The inline asm code is simply printed to the machine code .s file when
727 assembly code is generated.
728</p>
729</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]730
731
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]732<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]733<div class="doc_section"> <a name="typesystem">Type System</a> </div>
734<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]735
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]736<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]737
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]738<p>The LLVM type system is one of the most important features of the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]739intermediate representation. Being typed enables a number of
740optimizations to be performed on the IR directly, without having to do
741extra analyses on the side before the transformation. A strong type
742system makes it easier to read the generated code and enables novel
743analyses and transformations that are not feasible to perform on normal
744three address code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]745
746</div>
747
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]748<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]749<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]750<div class="doc_text">
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]751<p>The primitive types are the fundamental building blocks of the LLVM
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]752system. The current set of primitive types is as follows:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]753
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]754<table class="layout">
755 <tr class="layout">
756 <td class="left">
757 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]758 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]759 <tr><th>Type</th><th>Description</th></tr>
760 <tr><td><tt>void</tt></td><td>No value</td></tr>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]761 <tr><td><tt>i8</tt></td><td>Signless 8-bit value</td></tr>
762 <tr><td><tt>i32</tt></td><td>Signless 32-bit value</td></tr>
Misha Brukmancfa87bc2005-04-22 18:02:52 +0000[diff] [blame]763 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]764 <tr><td><tt>label</tt></td><td>Branch destination</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]765 </tbody>
766 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]767 </td>
768 <td class="right">
769 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]770 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]771 <tr><th>Type</th><th>Description</th></tr>
772 <tr><td><tt>bool</tt></td><td>True or False value</td></tr>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]773 <tr><td><tt>i16</tt></td><td>Signless 16-bit value</td></tr>
774 <tr><td><tt>i64</tt></td><td>Signless 64-bit value</td></tr>
775 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]776 </tbody>
777 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]778 </td>
779 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]780</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]781</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]782
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]783<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]784<div class="doc_subsubsection"> <a name="t_classifications">Type
785Classifications</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]786<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]787<p>These different primitive types fall into a few useful
788classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]789
790<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]791 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]792 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]793 <tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]794 <td><a name="t_integer">integer</a></td>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]795 <td><tt>i8, i16, i32, i64</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]796 </tr>
797 <tr>
798 <td><a name="t_integral">integral</a></td>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]799 <td><tt>bool, i8, i16, i32, i64</tt>
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]800 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]801 </tr>
802 <tr>
803 <td><a name="t_floating">floating point</a></td>
804 <td><tt>float, double</tt></td>
805 </tr>
806 <tr>
807 <td><a name="t_firstclass">first class</a></td>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]808 <td><tt>bool, i8, i16, i32, i64, float, double, <br/>
809 <a href="#t_pointer">pointer</a>,<a href="#t_packed">packed</a></tt>
810 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]811 </tr>
812 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]813</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]814
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]815<p>The <a href="#t_firstclass">first class</a> types are perhaps the
816most important. Values of these types are the only ones which can be
817produced by instructions, passed as arguments, or used as operands to
818instructions. This means that all structures and arrays must be
819manipulated either by pointer or by component.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]820</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]821
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]822<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]823<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]824
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]825<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]826
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]827<p>The real power in LLVM comes from the derived types in the system.
828This is what allows a programmer to represent arrays, functions,
829pointers, and other useful types. Note that these derived types may be
830recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]831
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]832</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]833
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]834<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]835<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]836
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]837<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]838
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]839<h5>Overview:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]840
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]841<p>The array type is a very simple derived type that arranges elements
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]842sequentially in memory. The array type requires a size (number of
843elements) and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]844
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]845<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]846
847<pre>
848 [&lt;# elements&gt; x &lt;elementtype&gt;]
849</pre>
850
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]851<p>The number of elements is a constant integer value; elementtype may
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]852be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]853
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]854<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]855<table class="layout">
856 <tr class="layout">
857 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]858 <tt>[40 x i32 ]</tt><br/>
859 <tt>[41 x i32 ]</tt><br/>
860 <tt>[40 x i32]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]861 </td>
862 <td class="left">
863 Array of 40 integer values.<br/>
864 Array of 41 integer values.<br/>
865 Array of 40 unsigned integer values.<br/>
866 </td>
867 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]868</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]869<p>Here are some examples of multidimensional arrays:</p>
870<table class="layout">
871 <tr class="layout">
872 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]873 <tt>[3 x [4 x i32]]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]874 <tt>[12 x [10 x float]]</tt><br/>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]875 <tt>[2 x [3 x [4 x i32]]]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]876 </td>
877 <td class="left">
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]878 3x4 array of integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]879 12x10 array of single precision floating point values.<br/>
880 2x3x4 array of unsigned integer values.<br/>
881 </td>
882 </tr>
883</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]884
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]885<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
886length array. Normally, accesses past the end of an array are undefined in
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]887LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
888As a special case, however, zero length arrays are recognized to be variable
889length. This allows implementation of 'pascal style arrays' with the LLVM
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]890type "{ i32, [0 x float]}", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]891
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]892</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]893
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]894<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]895<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]896<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]897<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]898<p>The function type can be thought of as a function signature. It
899consists of a return type and a list of formal parameter types.
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]900Function types are usually used to build virtual function tables
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]901(which are structures of pointers to functions), for indirect function
902calls, and when defining a function.</p>
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]903<p>
904The return type of a function type cannot be an aggregate type.
905</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]906<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]907<pre> &lt;returntype&gt; (&lt;parameter list&gt;)<br></pre>
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]908<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]909specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]910which indicates that the function takes a variable number of arguments.
911Variable argument functions can access their arguments with the <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]912 href="#int_varargs">variable argument handling intrinsic</a> functions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]913<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]914<table class="layout">
915 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]916 <td class="left"><tt>i32 (i32)</tt></td>
917 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]918 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]919 </tr><tr class="layout">
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]920 <td class="left"><tt>float&nbsp;(i16&nbsp;@sext,&nbsp;i32&nbsp;*)&nbsp;*
921 </tt></td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]922 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
923 an <tt>i16</tt> that should be sign extended and a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]924 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]925 <tt>float</tt>.
926 </td>
927 </tr><tr class="layout">
928 <td class="left"><tt>i32 (i8*, ...)</tt></td>
929 <td class="left">A vararg function that takes at least one
930 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (signed char in C),
931 which returns an integer. This is the signature for <tt>printf</tt> in
932 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]933 </td>
934 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]935</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]936
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]937</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]938<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]939<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]940<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]941<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]942<p>The structure type is used to represent a collection of data members
943together in memory. The packing of the field types is defined to match
944the ABI of the underlying processor. The elements of a structure may
945be any type that has a size.</p>
946<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
947and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
948field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
949instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]950<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]951<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]952<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]953<table class="layout">
954 <tr class="layout">
955 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]956 <tt>{ i32, i32, i32 }</tt><br/>
957 <tt>{ float, i32 (i32) * }</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]958 </td>
959 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]960 a triple of three <tt>i32</tt> values<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]961 A pair, where the first element is a <tt>float</tt> and the second element
962 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]963 that takes an <tt>i32</tt>, returning an <tt>i32</tt>.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]964 </td>
965 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]966</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]967</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]968
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]969<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]970<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
971</div>
972<div class="doc_text">
973<h5>Overview:</h5>
974<p>The packed structure type is used to represent a collection of data members
975together in memory. There is no padding between fields. Further, the alignment
976of a packed structure is 1 byte. The elements of a packed structure may
977be any type that has a size.</p>
978<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
979and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
980field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
981instruction.</p>
982<h5>Syntax:</h5>
983<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
984<h5>Examples:</h5>
985<table class="layout">
986 <tr class="layout">
987 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]988 <tt> &lt; { i32, i32, i32 } &gt; </tt><br/>
989 <tt> &lt; { float, i32 (i32) * } &gt; </tt><br/>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]990 </td>
991 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]992 a triple of three <tt>i32</tt> values<br/>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]993 A pair, where the first element is a <tt>float</tt> and the second element
994 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]995 that takes an <tt>i32</tt>, returning an <tt>i32</tt>.<br/>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]996 </td>
997 </tr>
998</table>
999</div>
1000
1001<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1002<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1003<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1004<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1005<p>As in many languages, the pointer type represents a pointer or
1006reference to another object, which must live in memory.</p>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1007<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1008<pre> &lt;type&gt; *<br></pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1009<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1010<table class="layout">
1011 <tr class="layout">
1012 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1013 <tt>[4x i32]*</tt><br/>
1014 <tt>i32 (i32 *) *</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1015 </td>
1016 <td class="left">
1017 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]1018 four <tt>i32</tt> values<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1019 A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1020 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
1021 <tt>i32</tt>.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1022 </td>
1023 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1024</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1025</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1026
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1027<!-- _______________________________________________________________________ -->
1028<div class="doc_subsubsection"> <a name="t_packed">Packed Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1029<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1030
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1031<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1032
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1033<p>A packed type is a simple derived type that represents a vector
1034of elements. Packed types are used when multiple primitive data
1035are operated in parallel using a single instruction (SIMD).
1036A packed type requires a size (number of
Chris Lattnerb8d172f2005-11-10 01:44:22 +0000[diff] [blame]1037elements) and an underlying primitive data type. Vectors must have a power
1038of two length (1, 2, 4, 8, 16 ...). Packed types are
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1039considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1040
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1041<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1042
1043<pre>
1044 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1045</pre>
1046
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1047<p>The number of elements is a constant integer value; elementtype may
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1048be any integral or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1049
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1050<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1051
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1052<table class="layout">
1053 <tr class="layout">
1054 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1055 <tt>&lt;4 x i32&gt;</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1056 <tt>&lt;8 x float&gt;</tt><br/>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1057 <tt>&lt;2 x i32&gt;</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1058 </td>
1059 <td class="left">
1060 Packed vector of 4 integer values.<br/>
1061 Packed vector of 8 floating-point values.<br/>
1062 Packed vector of 2 unsigned integer values.<br/>
1063 </td>
1064 </tr>
1065</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1066</div>
1067
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1068<!-- _______________________________________________________________________ -->
1069<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1070<div class="doc_text">
1071
1072<h5>Overview:</h5>
1073
1074<p>Opaque types are used to represent unknown types in the system. This
1075corresponds (for example) to the C notion of a foward declared structure type.
1076In LLVM, opaque types can eventually be resolved to any type (not just a
1077structure type).</p>
1078
1079<h5>Syntax:</h5>
1080
1081<pre>
1082 opaque
1083</pre>
1084
1085<h5>Examples:</h5>
1086
1087<table class="layout">
1088 <tr class="layout">
1089 <td class="left">
1090 <tt>opaque</tt>
1091 </td>
1092 <td class="left">
1093 An opaque type.<br/>
1094 </td>
1095 </tr>
1096</table>
1097</div>
1098
1099
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1100<!-- *********************************************************************** -->
1101<div class="doc_section"> <a name="constants">Constants</a> </div>
1102<!-- *********************************************************************** -->
1103
1104<div class="doc_text">
1105
1106<p>LLVM has several different basic types of constants. This section describes
1107them all and their syntax.</p>
1108
1109</div>
1110
1111<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1112<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1113
1114<div class="doc_text">
1115
1116<dl>
1117 <dt><b>Boolean constants</b></dt>
1118
1119 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
1120 constants of the <tt><a href="#t_primitive">bool</a></tt> type.
1121 </dd>
1122
1123 <dt><b>Integer constants</b></dt>
1124
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1125 <dd>Standard integers (such as '4') are constants of the <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1126 href="#t_integer">integer</a> type. Negative numbers may be used with signed
1127 integer types.
1128 </dd>
1129
1130 <dt><b>Floating point constants</b></dt>
1131
1132 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1133 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1134 notation (see below). Floating point constants must have a <a
1135 href="#t_floating">floating point</a> type. </dd>
1136
1137 <dt><b>Null pointer constants</b></dt>
1138
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1139 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1140 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1141
1142</dl>
1143
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1144<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1145of floating point constants. For example, the form '<tt>double
11460x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
11474.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1148(and the only time that they are generated by the disassembler) is when a
1149floating point constant must be emitted but it cannot be represented as a
1150decimal floating point number. For example, NaN's, infinities, and other
1151special values are represented in their IEEE hexadecimal format so that
1152assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1153
1154</div>
1155
1156<!-- ======================================================================= -->
1157<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1158</div>
1159
1160<div class="doc_text">
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1161<p>Aggregate constants arise from aggregation of simple constants
1162and smaller aggregate constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1163
1164<dl>
1165 <dt><b>Structure constants</b></dt>
1166
1167 <dd>Structure constants are represented with notation similar to structure
1168 type definitions (a comma separated list of elements, surrounded by braces
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1169 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* %G }</tt>",
1170 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]1171 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1172 types of elements must match those specified by the type.
1173 </dd>
1174
1175 <dt><b>Array constants</b></dt>
1176
1177 <dd>Array constants are represented with notation similar to array type
1178 definitions (a comma separated list of elements, surrounded by square brackets
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1179 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1180 constants must have <a href="#t_array">array type</a>, and the number and
1181 types of elements must match those specified by the type.
1182 </dd>
1183
1184 <dt><b>Packed constants</b></dt>
1185
1186 <dd>Packed constants are represented with notation similar to packed type
1187 definitions (a comma separated list of elements, surrounded by
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1188 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32 42,
1189 i32 11, i32 74, i32 100 &gt;</tt>". Packed constants must have <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1190 href="#t_packed">packed type</a>, and the number and types of elements must
1191 match those specified by the type.
1192 </dd>
1193
1194 <dt><b>Zero initialization</b></dt>
1195
1196 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1197 value to zero of <em>any</em> type, including scalar and aggregate types.
1198 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]1199 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1200 initializers.
1201 </dd>
1202</dl>
1203
1204</div>
1205
1206<!-- ======================================================================= -->
1207<div class="doc_subsection">
1208 <a name="globalconstants">Global Variable and Function Addresses</a>
1209</div>
1210
1211<div class="doc_text">
1212
1213<p>The addresses of <a href="#globalvars">global variables</a> and <a
1214href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1215constants. These constants are explicitly referenced when the <a
1216href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1217href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1218file:</p>
1219
1220<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1221 %X = global i32 17
1222 %Y = global i32 42
1223 %Z = global [2 x i32*] [ i32* %X, i32* %Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1224</pre>
1225
1226</div>
1227
1228<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1229<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1230<div class="doc_text">
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1231 <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]1232 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1233 a constant is permitted.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1234
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1235 <p>Undefined values indicate to the compiler that the program is well defined
1236 no matter what value is used, giving the compiler more freedom to optimize.
1237 </p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1238</div>
1239
1240<!-- ======================================================================= -->
1241<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1242</div>
1243
1244<div class="doc_text">
1245
1246<p>Constant expressions are used to allow expressions involving other constants
1247to be used as constants. Constant expressions may be of any <a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1248href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1249that does not have side effects (e.g. load and call are not supported). The
1250following is the syntax for constant expressions:</p>
1251
1252<dl>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1253 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1254 <dd>Truncate a constant to another type. The bit size of CST must be larger
1255 than the bit size of TYPE. Both types must be integral.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1256
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1257 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1258 <dd>Zero extend a constant to another type. The bit size of CST must be
1259 smaller or equal to the bit size of TYPE. Both types must be integral.</dd>
1260
1261 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1262 <dd>Sign extend a constant to another type. The bit size of CST must be
1263 smaller or equal to the bit size of TYPE. Both types must be integral.</dd>
1264
1265 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1266 <dd>Truncate a floating point constant to another floating point type. The
1267 size of CST must be larger than the size of TYPE. Both types must be
1268 floating point.</dd>
1269
1270 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1271 <dd>Floating point extend a constant to another type. The size of CST must be
1272 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1273
1274 <dt><b><tt>fp2uint ( CST to TYPE )</tt></b></dt>
1275 <dd>Convert a floating point constant to the corresponding unsigned integer
1276 constant. TYPE must be an integer type. CST must be floating point. If the
1277 value won't fit in the integer type, the results are undefined.</dd>
1278
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1279 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1280 <dd>Convert a floating point constant to the corresponding signed integer
1281 constant. TYPE must be an integer type. CST must be floating point. If the
1282 value won't fit in the integer type, the results are undefined.</dd>
1283
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1284 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1285 <dd>Convert an unsigned integer constant to the corresponding floating point
1286 constant. TYPE must be floating point. CST must be of integer type. If the
1287 value won't fit in the floating point type, the results are undefined.</dd>
1288
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1289 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1290 <dd>Convert a signed integer constant to the corresponding floating point
1291 constant. TYPE must be floating point. CST must be of integer type. If the
1292 value won't fit in the floating point type, the results are undefined.</dd>
1293
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]1294 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1295 <dd>Convert a pointer typed constant to the corresponding integer constant
1296 TYPE must be an integer type. CST must be of pointer type. The CST value is
1297 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1298
1299 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1300 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1301 pointer type. CST must be of integer type. The CST value is zero extended,
1302 truncated, or unchanged to make it fit in a pointer size. This one is
1303 <i>really</i> dangerous!</dd>
1304
1305 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1306 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1307 identical (same number of bits). The conversion is done as if the CST value
1308 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]1309 with this operator, just the type. This can be used for conversion of
1310 packed types to any other type, as long as they have the same bit width. For
1311 pointers it is only valid to cast to another pointer type.
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1312 </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1313
1314 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1315
1316 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1317 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1318 instruction, the index list may have zero or more indexes, which are required
1319 to make sense for the type of "CSTPTR".</dd>
1320
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1321 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1322
1323 <dd>Perform the <a href="#i_select">select operation</a> on
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1324 constants.</dd>
1325
1326 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1327 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1328
1329 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1330 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1331
1332 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1333
1334 <dd>Perform the <a href="#i_extractelement">extractelement
1335 operation</a> on constants.
1336
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1337 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1338
1339 <dd>Perform the <a href="#i_insertelement">insertelement
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1340 operation</a> on constants.</dd>
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1341
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1342
1343 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1344
1345 <dd>Perform the <a href="#i_shufflevector">shufflevector
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1346 operation</a> on constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1347
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1348 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1349
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1350 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1351 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1352 binary</a> operations. The constraints on operands are the same as those for
1353 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1354 values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1355</dl>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1356</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]1357
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1358<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1359<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1360<!-- *********************************************************************** -->
1361
1362<!-- ======================================================================= -->
1363<div class="doc_subsection">
1364<a name="inlineasm">Inline Assembler Expressions</a>
1365</div>
1366
1367<div class="doc_text">
1368
1369<p>
1370LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1371Module-Level Inline Assembly</a>) through the use of a special value. This
1372value represents the inline assembler as a string (containing the instructions
1373to emit), a list of operand constraints (stored as a string), and a flag that
1374indicates whether or not the inline asm expression has side effects. An example
1375inline assembler expression is:
1376</p>
1377
1378<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1379 i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1380</pre>
1381
1382<p>
1383Inline assembler expressions may <b>only</b> be used as the callee operand of
1384a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1385</p>
1386
1387<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1388 %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]1389</pre>
1390
1391<p>
1392Inline asms with side effects not visible in the constraint list must be marked
1393as having side effects. This is done through the use of the
1394'<tt>sideeffect</tt>' keyword, like so:
1395</p>
1396
1397<pre>
1398 call void asm sideeffect "eieio", ""()
1399</pre>
1400
1401<p>TODO: The format of the asm and constraints string still need to be
1402documented here. Constraints on what can be done (e.g. duplication, moving, etc
1403need to be documented).
1404</p>
1405
1406</div>
1407
1408<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1409<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1410<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1411
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1412<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1413
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1414<p>The LLVM instruction set consists of several different
1415classifications of instructions: <a href="#terminators">terminator
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1416instructions</a>, <a href="#binaryops">binary instructions</a>,
1417<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1418 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1419instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1420
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1421</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1422
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1423<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1424<div class="doc_subsection"> <a name="terminators">Terminator
1425Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1426
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1427<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1428
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1429<p>As mentioned <a href="#functionstructure">previously</a>, every
1430basic block in a program ends with a "Terminator" instruction, which
1431indicates which block should be executed after the current block is
1432finished. These terminator instructions typically yield a '<tt>void</tt>'
1433value: they produce control flow, not values (the one exception being
1434the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1435<p>There are six different terminator instructions: the '<a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1436 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1437instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1438the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1439 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1440 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1441
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1442</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1443
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1444<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1445<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1446Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1447<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1448<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1449<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]1450 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1451</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1452<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1453<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1454value) from a function back to the caller.</p>
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]1455<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1456returns a value and then causes control flow, and one that just causes
1457control flow to occur.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1458<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1459<p>The '<tt>ret</tt>' instruction may return any '<a
1460 href="#t_firstclass">first class</a>' type. Notice that a function is
1461not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
1462instruction inside of the function that returns a value that does not
1463match the return type of the function.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1464<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1465<p>When the '<tt>ret</tt>' instruction is executed, control flow
1466returns back to the calling function's context. If the caller is a "<a
John Criswellfa081872004-06-25 15:16:57 +0000[diff] [blame]1467 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1468the instruction after the call. If the caller was an "<a
1469 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1470at the beginning of the "normal" destination block. If the instruction
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1471returns a value, that value shall set the call or invoke instruction's
1472return value.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1473<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1474<pre> ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1475 ret void <i>; Return from a void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1476</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1477</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1478<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1479<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1480<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1481<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1482<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]1483</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1484<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1485<p>The '<tt>br</tt>' instruction is used to cause control flow to
1486transfer to a different basic block in the current function. There are
1487two forms of this instruction, corresponding to a conditional branch
1488and an unconditional branch.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1489<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1490<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
1491single '<tt>bool</tt>' value and two '<tt>label</tt>' values. The
1492unconditional form of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>'
1493value as a target.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1494<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1495<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>bool</tt>'
1496argument is evaluated. If the value is <tt>true</tt>, control flows
1497to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1498control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1499<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1500<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
1501 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]1502</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1503<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1504<div class="doc_subsubsection">
1505 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1506</div>
1507
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1508<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1509<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1510
1511<pre>
1512 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1513</pre>
1514
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1515<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1516
1517<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1518several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1519instruction, allowing a branch to occur to one of many possible
1520destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1521
1522
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1523<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1524
1525<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1526comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1527an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1528table is not allowed to contain duplicate constant entries.</p>
1529
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1530<h5>Semantics:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1531
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1532<p>The <tt>switch</tt> instruction specifies a table of values and
1533destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1534table is searched for the given value. If the value is found, control flow is
1535transfered to the corresponding destination; otherwise, control flow is
1536transfered to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1537
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1538<h5>Implementation:</h5>
1539
1540<p>Depending on properties of the target machine and the particular
1541<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1542ways. For example, it could be generated as a series of chained conditional
1543branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1544
1545<h5>Example:</h5>
1546
1547<pre>
1548 <i>; Emulate a conditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1549 %Val = <a href="#i_zext">zext</a> bool %value to i32
1550 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1551
1552 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1553 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1554
1555 <i>; Implement a jump table:</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1556 switch i32 %val, label %otherwise [ i32 0, label %onzero
1557 i32 1, label %onone
1558 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1559</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1560</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1561
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1562<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1563<div class="doc_subsubsection">
1564 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1565</div>
1566
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1567<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1568
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1569<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1570
1571<pre>
1572 &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]1573 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1574</pre>
1575
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1576<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1577
1578<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1579function, with the possibility of control flow transfer to either the
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1580'<tt>normal</tt>' label or the
1581'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1582"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1583"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1584href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
1585continued at the dynamically nearest "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1586
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1587<h5>Arguments:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1588
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1589<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1590
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1591<ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1592 <li>
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1593 The optional "cconv" marker indicates which <a href="callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1594 convention</a> the call should use. If none is specified, the call defaults
1595 to using C calling conventions.
1596 </li>
1597 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1598 function value being invoked. In most cases, this is a direct function
1599 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1600 an arbitrary pointer to function value.
1601 </li>
1602
1603 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1604 function to be invoked. </li>
1605
1606 <li>'<tt>function args</tt>': argument list whose types match the function
1607 signature argument types. If the function signature indicates the function
1608 accepts a variable number of arguments, the extra arguments can be
1609 specified. </li>
1610
1611 <li>'<tt>normal label</tt>': the label reached when the called function
1612 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1613
1614 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1615 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1616
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1617</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1618
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1619<h5>Semantics:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1620
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1621<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1622href="#i_call">call</a></tt>' instruction in most regards. The primary
1623difference is that it establishes an association with a label, which is used by
1624the runtime library to unwind the stack.</p>
1625
1626<p>This instruction is used in languages with destructors to ensure that proper
1627cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1628exception. Additionally, this is important for implementation of
1629'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1630
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1631<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1632<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1633 %retval = invoke i32 %Test(i32 15) to label %Continue
1634 unwind label %TestCleanup <i>; {i32}:retval set</i>
1635 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Test(i32 15) to label %Continue
1636 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1637</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1638</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1639
1640
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1641<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1642
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1643<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1644Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1645
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1646<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1647
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1648<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1649<pre>
1650 unwind
1651</pre>
1652
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1653<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1654
1655<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
1656at the first callee in the dynamic call stack which used an <a
1657href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
1658primarily used to implement exception handling.</p>
1659
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1660<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1661
1662<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
1663immediately halt. The dynamic call stack is then searched for the first <a
1664href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
1665execution continues at the "exceptional" destination block specified by the
1666<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
1667dynamic call chain, undefined behavior results.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1668</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1669
1670<!-- _______________________________________________________________________ -->
1671
1672<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
1673Instruction</a> </div>
1674
1675<div class="doc_text">
1676
1677<h5>Syntax:</h5>
1678<pre>
1679 unreachable
1680</pre>
1681
1682<h5>Overview:</h5>
1683
1684<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
1685instruction is used to inform the optimizer that a particular portion of the
1686code is not reachable. This can be used to indicate that the code after a
1687no-return function cannot be reached, and other facts.</p>
1688
1689<h5>Semantics:</h5>
1690
1691<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
1692</div>
1693
1694
1695
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1696<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1697<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1698<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1699<p>Binary operators are used to do most of the computation in a
1700program. They require two operands, execute an operation on them, and
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1701produce a single value. The operands might represent
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1702multiple data, as is the case with the <a href="#t_packed">packed</a> data type.
1703The result value of a binary operator is not
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1704necessarily the same type as its operands.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1705<p>There are several different binary operators:</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1706</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1707<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1708<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
1709Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1710<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1711<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1712<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]1713</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1714<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1715<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1716<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1717<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1718 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
1719 This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1720Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1721<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1722<p>The value produced is the integer or floating point sum of the two
1723operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1724<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1725<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]1726</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1727</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1728<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1729<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
1730Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1731<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1732<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1733<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]1734</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1735<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1736<p>The '<tt>sub</tt>' instruction returns the difference of its two
1737operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1738<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
1739instruction present in most other intermediate representations.</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>sub</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1742 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1743values.
1744This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1745Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1746<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1747<p>The value produced is the integer or floating point difference of
1748the two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1749<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1750<pre> &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
1751 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1752</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1753</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1754<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1755<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
1756Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1757<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1758<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1759<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]1760</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1761<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1762<p>The '<tt>mul</tt>' instruction returns the product of its two
1763operands.</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>mul</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 product of the
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1772two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1773<p>There is no signed vs unsigned multiplication. The appropriate
1774action is taken based on the type of the operand.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1775<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1776<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]1777</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1778</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1779<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1780<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
1781</a></div>
1782<div class="doc_text">
1783<h5>Syntax:</h5>
1784<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1785</pre>
1786<h5>Overview:</h5>
1787<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
1788operands.</p>
1789<h5>Arguments:</h5>
1790<p>The two arguments to the '<tt>udiv</tt>' instruction must be
1791<a href="#t_integer">integer</a> values. Both arguments must have identical
1792types. This instruction can also take <a href="#t_packed">packed</a> versions
1793of the values in which case the elements must be integers.</p>
1794<h5>Semantics:</h5>
1795<p>The value produced is the unsigned integer quotient of the two operands. This
1796instruction always performs an unsigned division operation, regardless of
1797whether the arguments are unsigned or not.</p>
1798<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1799<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]1800</pre>
1801</div>
1802<!-- _______________________________________________________________________ -->
1803<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
1804</a> </div>
1805<div class="doc_text">
1806<h5>Syntax:</h5>
1807<pre> &lt;result&gt; = sdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1808</pre>
1809<h5>Overview:</h5>
1810<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
1811operands.</p>
1812<h5>Arguments:</h5>
1813<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
1814<a href="#t_integer">integer</a> values. Both arguments must have identical
1815types. This instruction can also take <a href="#t_packed">packed</a> versions
1816of the values in which case the elements must be integers.</p>
1817<h5>Semantics:</h5>
1818<p>The value produced is the signed integer quotient of the two operands. This
1819instruction always performs a signed division operation, regardless of whether
1820the arguments are signed or not.</p>
1821<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1822<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]1823</pre>
1824</div>
1825<!-- _______________________________________________________________________ -->
1826<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1827Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1828<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1829<h5>Syntax:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1830<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]1831</pre>
1832<h5>Overview:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1833<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1834operands.</p>
1835<h5>Arguments:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1836<p>The two arguments to the '<tt>div</tt>' instruction must be
1837<a href="#t_floating">floating point</a> values. Both arguments must have
1838identical types. This instruction can also take <a href="#t_packed">packed</a>
1839versions of the values in which case the elements must be floating point.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1840<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1841<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1842<h5>Example:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1843<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]1844</pre>
1845</div>
1846<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1847<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
1848</div>
1849<div class="doc_text">
1850<h5>Syntax:</h5>
1851<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1852</pre>
1853<h5>Overview:</h5>
1854<p>The '<tt>urem</tt>' instruction returns the remainder from the
1855unsigned division of its two arguments.</p>
1856<h5>Arguments:</h5>
1857<p>The two arguments to the '<tt>urem</tt>' instruction must be
1858<a href="#t_integer">integer</a> values. Both arguments must have identical
1859types.</p>
1860<h5>Semantics:</h5>
1861<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
1862This instruction always performs an unsigned division to get the remainder,
1863regardless of whether the arguments are unsigned or not.</p>
1864<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1865<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]1866</pre>
1867
1868</div>
1869<!-- _______________________________________________________________________ -->
1870<div class="doc_subsubsection"> <a name="i_srem">'<tt>srem</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1871Instruction</a> </div>
1872<div class="doc_text">
1873<h5>Syntax:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1874<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]1875</pre>
1876<h5>Overview:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1877<p>The '<tt>srem</tt>' instruction returns the remainder from the
1878signed division of its two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1879<h5>Arguments:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1880<p>The two arguments to the '<tt>srem</tt>' instruction must be
1881<a href="#t_integer">integer</a> values. Both arguments must have identical
1882types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1883<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1884<p>This instruction returns the <i>remainder</i> of a division (where the result
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1885has the same sign as the divisor), not the <i>modulus</i> (where the
1886result has the same sign as the dividend) of a value. For more
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1887information about the difference, see <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1888 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
1889Math Forum</a>.</p>
1890<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1891<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]1892</pre>
1893
1894</div>
1895<!-- _______________________________________________________________________ -->
1896<div class="doc_subsubsection"> <a name="i_frem">'<tt>frem</tt>'
1897Instruction</a> </div>
1898<div class="doc_text">
1899<h5>Syntax:</h5>
1900<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1901</pre>
1902<h5>Overview:</h5>
1903<p>The '<tt>frem</tt>' instruction returns the remainder from the
1904division of its two operands.</p>
1905<h5>Arguments:</h5>
1906<p>The two arguments to the '<tt>frem</tt>' instruction must be
1907<a href="#t_floating">floating point</a> values. Both arguments must have
1908identical types.</p>
1909<h5>Semantics:</h5>
1910<p>This instruction returns the <i>remainder</i> of a division.</p>
1911<h5>Example:</h5>
1912<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]1913</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1914</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]1915
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1916<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1917<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
1918Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1919<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1920<p>Bitwise binary operators are used to do various forms of
1921bit-twiddling in a program. They are generally very efficient
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1922instructions and can commonly be strength reduced from other
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1923instructions. They require two operands, execute an operation on them,
1924and produce a single value. The resulting value of the bitwise binary
1925operators is always the same type as its first operand.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1926</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1927<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1928<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
1929Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1930<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1931<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1932<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]1933</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1934<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1935<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
1936its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1937<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1938<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1939 href="#t_integral">integral</a> values. Both arguments must have
1940identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1941<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1942<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1943<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1944<div style="align: center">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1945<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1946 <tbody>
1947 <tr>
1948 <td>In0</td>
1949 <td>In1</td>
1950 <td>Out</td>
1951 </tr>
1952 <tr>
1953 <td>0</td>
1954 <td>0</td>
1955 <td>0</td>
1956 </tr>
1957 <tr>
1958 <td>0</td>
1959 <td>1</td>
1960 <td>0</td>
1961 </tr>
1962 <tr>
1963 <td>1</td>
1964 <td>0</td>
1965 <td>0</td>
1966 </tr>
1967 <tr>
1968 <td>1</td>
1969 <td>1</td>
1970 <td>1</td>
1971 </tr>
1972 </tbody>
1973</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1974</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1975<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1976<pre> &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
1977 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
1978 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1979</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1980</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1981<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1982<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1983<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1984<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1985<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]1986</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1987<h5>Overview:</h5>
1988<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
1989or of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1990<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1991<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1992 href="#t_integral">integral</a> values. Both arguments must have
1993identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1994<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1995<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1996<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1997<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1998<table border="1" cellspacing="0" cellpadding="4">
1999 <tbody>
2000 <tr>
2001 <td>In0</td>
2002 <td>In1</td>
2003 <td>Out</td>
2004 </tr>
2005 <tr>
2006 <td>0</td>
2007 <td>0</td>
2008 <td>0</td>
2009 </tr>
2010 <tr>
2011 <td>0</td>
2012 <td>1</td>
2013 <td>1</td>
2014 </tr>
2015 <tr>
2016 <td>1</td>
2017 <td>0</td>
2018 <td>1</td>
2019 </tr>
2020 <tr>
2021 <td>1</td>
2022 <td>1</td>
2023 <td>1</td>
2024 </tr>
2025 </tbody>
2026</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2027</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2028<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2029<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2030 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2031 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2032</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2033</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2034<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2035<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2036Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2037<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2038<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2039<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]2040</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2041<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2042<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2043or of its two operands. The <tt>xor</tt> is used to implement the
2044"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2045<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2046<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2047 href="#t_integral">integral</a> values. Both arguments must have
2048identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2049<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2050<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2051<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2052<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2053<table border="1" cellspacing="0" cellpadding="4">
2054 <tbody>
2055 <tr>
2056 <td>In0</td>
2057 <td>In1</td>
2058 <td>Out</td>
2059 </tr>
2060 <tr>
2061 <td>0</td>
2062 <td>0</td>
2063 <td>0</td>
2064 </tr>
2065 <tr>
2066 <td>0</td>
2067 <td>1</td>
2068 <td>1</td>
2069 </tr>
2070 <tr>
2071 <td>1</td>
2072 <td>0</td>
2073 <td>1</td>
2074 </tr>
2075 <tr>
2076 <td>1</td>
2077 <td>1</td>
2078 <td>0</td>
2079 </tr>
2080 </tbody>
2081</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2082</div>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2083<p> </p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2084<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2085<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2086 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2087 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2088 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2089</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2090</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2091<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2092<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2093Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2094<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2095<h5>Syntax:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2096<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]2097</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2098<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2099<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2100the left a specified number of bits.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2101<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2102<p>The first argument to the '<tt>shl</tt>' instruction must be an <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2103 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]2104type.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2105<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2106<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]2107<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2108<pre> &lt;result&gt; = shl i32 4, i8 %var <i>; yields {i32}:result = 4 &lt;&lt; %var</i>
2109 &lt;result&gt; = shl i32 4, i8 2 <i>; yields {i32}:result = 16</i>
2110 &lt;result&gt; = shl i32 1, i8 10 <i>; yields {i32}:result = 1024</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2111</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2112</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2113<!-- _______________________________________________________________________ -->
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2114<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2115Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2116<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2117<h5>Syntax:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2118<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]2119</pre>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2120
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2121<h5>Overview:</h5>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2122<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
2123operand shifted to the right a specified number of bits.</p>
2124
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2125<h5>Arguments:</h5>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2126<p>The first argument to the '<tt>lshr</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>' type.</p>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2128
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2129<h5>Semantics:</h5>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2130<p>This instruction always performs a logical shift right operation, regardless
2131of whether the arguments are unsigned or not. The <tt>var2</tt> most significant
2132bits will be filled with zero bits after the shift.</p>
2133
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2134<h5>Example:</h5>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2135<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2136 &lt;result&gt; = lshr i32 4, i8 1 <i>; yields {i32}:result = 2</i>
2137 &lt;result&gt; = lshr i32 4, i8 2 <i>; yields {i32}:result = 1</i>
2138 &lt;result&gt; = lshr i8 4, i8 3 <i>; yields {i8 }:result = 0</i>
2139 &lt;result&gt; = lshr i8 -2, i8 1 <i>; yields {i8 }:result = 0x7FFFFFFF </i>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2140</pre>
2141</div>
2142
2143<!-- ======================================================================= -->
2144<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2145Instruction</a> </div>
2146<div class="doc_text">
2147
2148<h5>Syntax:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2149<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]2150</pre>
2151
2152<h5>Overview:</h5>
2153<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
2154operand shifted to the right a specified number of bits.</p>
2155
2156<h5>Arguments:</h5>
2157<p>The first argument to the '<tt>ashr</tt>' instruction must be an
2158<a href="#t_integer">integer</a> type. The second argument must be an
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2159'<tt>i8</tt>' type.</p>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2160
2161<h5>Semantics:</h5>
2162<p>This instruction always performs an arithmetic shift right operation,
2163regardless of whether the arguments are signed or not. The <tt>var2</tt> most
2164significant bits will be filled with the sign bit of <tt>var1</tt>.</p>
2165
2166<h5>Example:</h5>
2167<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2168 &lt;result&gt; = ashr i32 4, i8 1 <i>; yields {i32}:result = 2</i>
2169 &lt;result&gt; = ashr i32 4, i8 2 <i>; yields {i32}:result = 1</i>
2170 &lt;result&gt; = ashr i8 4, i8 3 <i>; yields {i8}:result = 0</i>
2171 &lt;result&gt; = ashr i8 -2, i8 1 <i>; yields {i8 }:result = -1</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2172</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2173</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2174
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2175<!-- ======================================================================= -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2176<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2177 <a name="vectorops">Vector Operations</a>
2178</div>
2179
2180<div class="doc_text">
2181
2182<p>LLVM supports several instructions to represent vector operations in a
2183target-independent manner. This instructions cover the element-access and
2184vector-specific operations needed to process vectors effectively. While LLVM
2185does directly support these vector operations, many sophisticated algorithms
2186will want to use target-specific intrinsics to take full advantage of a specific
2187target.</p>
2188
2189</div>
2190
2191<!-- _______________________________________________________________________ -->
2192<div class="doc_subsubsection">
2193 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2194</div>
2195
2196<div class="doc_text">
2197
2198<h5>Syntax:</h5>
2199
2200<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2201 &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]2202</pre>
2203
2204<h5>Overview:</h5>
2205
2206<p>
2207The '<tt>extractelement</tt>' instruction extracts a single scalar
2208element from a packed vector at a specified index.
2209</p>
2210
2211
2212<h5>Arguments:</h5>
2213
2214<p>
2215The first operand of an '<tt>extractelement</tt>' instruction is a
2216value of <a href="#t_packed">packed</a> type. The second operand is
2217an index indicating the position from which to extract the element.
2218The index may be a variable.</p>
2219
2220<h5>Semantics:</h5>
2221
2222<p>
2223The result is a scalar of the same type as the element type of
2224<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2225<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2226results are undefined.
2227</p>
2228
2229<h5>Example:</h5>
2230
2231<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2232 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2233</pre>
2234</div>
2235
2236
2237<!-- _______________________________________________________________________ -->
2238<div class="doc_subsubsection">
2239 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2240</div>
2241
2242<div class="doc_text">
2243
2244<h5>Syntax:</h5>
2245
2246<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2247 &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]2248</pre>
2249
2250<h5>Overview:</h5>
2251
2252<p>
2253The '<tt>insertelement</tt>' instruction inserts a scalar
2254element into a packed vector at a specified index.
2255</p>
2256
2257
2258<h5>Arguments:</h5>
2259
2260<p>
2261The first operand of an '<tt>insertelement</tt>' instruction is a
2262value of <a href="#t_packed">packed</a> type. The second operand is a
2263scalar value whose type must equal the element type of the first
2264operand. The third operand is an index indicating the position at
2265which to insert the value. The index may be a variable.</p>
2266
2267<h5>Semantics:</h5>
2268
2269<p>
2270The result is a packed vector of the same type as <tt>val</tt>. Its
2271element values are those of <tt>val</tt> except at position
2272<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2273exceeds the length of <tt>val</tt>, the results are undefined.
2274</p>
2275
2276<h5>Example:</h5>
2277
2278<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2279 %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]2280</pre>
2281</div>
2282
2283<!-- _______________________________________________________________________ -->
2284<div class="doc_subsubsection">
2285 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2286</div>
2287
2288<div class="doc_text">
2289
2290<h5>Syntax:</h5>
2291
2292<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2293 &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]2294</pre>
2295
2296<h5>Overview:</h5>
2297
2298<p>
2299The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2300from two input vectors, returning a vector of the same type.
2301</p>
2302
2303<h5>Arguments:</h5>
2304
2305<p>
2306The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2307with types that match each other and types that match the result of the
2308instruction. The third argument is a shuffle mask, which has the same number
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2309of elements as the other vector type, but whose element type is always 'i32'.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2310</p>
2311
2312<p>
2313The shuffle mask operand is required to be a constant vector with either
2314constant integer or undef values.
2315</p>
2316
2317<h5>Semantics:</h5>
2318
2319<p>
2320The elements of the two input vectors are numbered from left to right across
2321both of the vectors. The shuffle mask operand specifies, for each element of
2322the result vector, which element of the two input registers the result element
2323gets. The element selector may be undef (meaning "don't care") and the second
2324operand may be undef if performing a shuffle from only one vector.
2325</p>
2326
2327<h5>Example:</h5>
2328
2329<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2330 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
2331 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
2332 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2333 &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]2334</pre>
2335</div>
2336
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]2337
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2338<!-- ======================================================================= -->
2339<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2340 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2341</div>
2342
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2343<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2344
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2345<p>A key design point of an SSA-based representation is how it
2346represents memory. In LLVM, no memory locations are in SSA form, which
2347makes things very simple. This section describes how to read, write,
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2348allocate, and free memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2349
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2350</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2351
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2352<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2353<div class="doc_subsubsection">
2354 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2355</div>
2356
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2357<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2358
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2359<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2360
2361<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2362 &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]2363</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2364
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2365<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2366
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2367<p>The '<tt>malloc</tt>' instruction allocates memory from the system
2368heap and returns a pointer to it.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2369
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2370<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2371
2372<p>The '<tt>malloc</tt>' instruction allocates
2373<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswell6e4ca612004-02-24 16:13:56 +0000[diff] [blame]2374bytes of memory from the operating system and returns a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2375appropriate type to the program. If "NumElements" is specified, it is the
2376number of elements allocated. If an alignment is specified, the value result
2377of the allocation is guaranteed to be aligned to at least that boundary. If
2378not specified, or if zero, the target can choose to align the allocation on any
2379convenient boundary.</p>
2380
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2381<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2382
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2383<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2384
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2385<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
2386a pointer is returned.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2387
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2388<h5>Example:</h5>
2389
2390<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2391 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2392
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2393 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
2394 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
2395 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
2396 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
2397 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2398</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2399</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2400
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2401<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2402<div class="doc_subsubsection">
2403 <a name="i_free">'<tt>free</tt>' Instruction</a>
2404</div>
2405
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2406<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2407
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2408<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2409
2410<pre>
2411 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2412</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2413
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2414<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2415
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2416<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2417memory heap to be reallocated in the future.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2418
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2419<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2420
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2421<p>'<tt>value</tt>' shall be a pointer value that points to a value
2422that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
2423instruction.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2424
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2425<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2426
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2427<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2428after this instruction executes.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2429
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2430<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2431
2432<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2433 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
2434 free [4 x i8]* %array
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2435</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2436</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2437
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2438<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2439<div class="doc_subsubsection">
2440 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
2441</div>
2442
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2443<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2444
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2445<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2446
2447<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2448 &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]2449</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2450
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2451<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2452
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2453<p>The '<tt>alloca</tt>' instruction allocates memory on the current
2454stack frame of the procedure that is live until the current function
2455returns to its caller.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2456
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2457<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2458
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2459<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2460bytes of memory on the runtime stack, returning a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2461appropriate type to the program. If "NumElements" is specified, it is the
2462number of elements allocated. If an alignment is specified, the value result
2463of the allocation is guaranteed to be aligned to at least that boundary. If
2464not specified, or if zero, the target can choose to align the allocation on any
2465convenient boundary.</p>
2466
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2467<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2468
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2469<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2470
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2471<p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2472memory is automatically released when the function returns. The '<tt>alloca</tt>'
2473instruction is commonly used to represent automatic variables that must
2474have an address available. When the function returns (either with the <tt><a
John Criswelldae2e932005-05-12 16:55:34 +0000[diff] [blame]2475 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]2476instructions), the memory is reclaimed.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2477
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2478<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2479
2480<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2481 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
2482 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
2483 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
2484 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2485</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2486</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2487
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2488<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2489<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
2490Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2491<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2492<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2493<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]2494<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2495<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2496<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2497<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2498address from which to load. The pointer must point to a <a
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]2499 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2500marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2501the number or order of execution of this <tt>load</tt> with other
2502volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
2503instructions. </p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2504<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2505<p>The location of memory pointed to is loaded.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2506<h5>Examples:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2507<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2508 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2509 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2510 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2511</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2512</div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2513<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2514<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
2515Instruction</a> </div>
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]2516<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2517<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2518<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]2519 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]2520</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2521<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2522<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2523<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2524<p>There are two arguments to the '<tt>store</tt>' instruction: a value
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2525to 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]2526operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2527operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2528optimizer is not allowed to modify the number or order of execution of
2529this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
2530 href="#i_store">store</a></tt> instructions.</p>
2531<h5>Semantics:</h5>
2532<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
2533at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2534<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2535<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2536 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2537 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2538 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2539</pre>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2540</div>
2541
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2542<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2543<div class="doc_subsubsection">
2544 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
2545</div>
2546
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2547<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2548<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2549<pre>
2550 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
2551</pre>
2552
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2553<h5>Overview:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2554
2555<p>
2556The '<tt>getelementptr</tt>' instruction is used to get the address of a
2557subelement of an aggregate data structure.</p>
2558
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2559<h5>Arguments:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2560
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2561<p>This instruction takes a list of integer operands that indicate what
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2562elements of the aggregate object to index to. The actual types of the arguments
2563provided depend on the type of the first pointer argument. The
2564'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2565levels 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]2566structure, only <tt>i32</tt> integer constants are allowed. When indexing
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2567into an array or pointer, only integers of 32 or 64 bits are allowed, and will
2568be sign extended to 64-bit values.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2569
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2570<p>For example, let's consider a C code fragment and how it gets
2571compiled to LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2572
2573<pre>
2574 struct RT {
2575 char A;
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2576 i32 B[10][20];
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2577 char C;
2578 };
2579 struct ST {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2580 i32 X;
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2581 double Y;
2582 struct RT Z;
2583 };
2584
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2585 define i32 *foo(struct ST *s) {
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2586 return &amp;s[1].Z.B[5][13];
2587 }
2588</pre>
2589
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2590<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2591
2592<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2593 %RT = type { i8 , [10 x [20 x i32]], i8 }
2594 %ST = type { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2595
Brian Gaeke7283e7c2004-07-02 21:08:14 +0000[diff] [blame]2596 implementation
2597
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2598 define i32* %foo(%ST* %s) {
Brian Gaeke7283e7c2004-07-02 21:08:14 +0000[diff] [blame]2599 entry:
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2600 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
2601 ret i32* %reg
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2602 }
2603</pre>
2604
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2605<h5>Semantics:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2606
2607<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2608on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2609and <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]2610<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]2611to 64-bits. <a href="#t_struct">Structure</a> types, require <tt>i32</tt>
Reid Spencer42ddd842006-12-03 16:53:48 +0000[diff] [blame]2612<b>constants</b>.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2613
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2614<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]2615type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2616}</tt>' type, a structure. The second index indexes into the third element of
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2617the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
2618i8 }</tt>' type, another structure. The third index indexes into the second
2619element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2620array. The two dimensions of the array are subscripted into, yielding an
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2621'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
2622to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2623
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2624<p>Note that it is perfectly legal to index partially through a
2625structure, returning a pointer to an inner element. Because of this,
2626the LLVM code for the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2627
2628<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2629 define i32* %foo(%ST* %s) {
2630 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
2631 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
2632 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
2633 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
2634 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
2635 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2636 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2637</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2638
2639<p>Note that it is undefined to access an array out of bounds: array and
2640pointer indexes must always be within the defined bounds of the array type.
2641The one exception for this rules is zero length arrays. These arrays are
2642defined to be accessible as variable length arrays, which requires access
2643beyond the zero'th element.</p>
2644
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2645<p>The getelementptr instruction is often confusing. For some more insight
2646into how it works, see <a href="GetElementPtr.html">the getelementptr
2647FAQ</a>.</p>
2648
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2649<h5>Example:</h5>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2650
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2651<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2652 <i>; yields [12 x i8]*:aptr</i>
2653 %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2654</pre>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2655</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2656
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2657<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]2658<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2659</div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2660<div class="doc_text">
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]2661<p>The instructions in this category are the conversion instructions (casting)
2662which all take a single operand and a type. They perform various bit conversions
2663on the operand.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2664</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2665
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2666<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2667<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2668 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
2669</div>
2670<div class="doc_text">
2671
2672<h5>Syntax:</h5>
2673<pre>
2674 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2675</pre>
2676
2677<h5>Overview:</h5>
2678<p>
2679The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
2680</p>
2681
2682<h5>Arguments:</h5>
2683<p>
2684The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
2685be an <a href="#t_integer">integer</a> type, and a type that specifies the size
2686and type of the result, which must be an <a href="#t_integral">integral</a>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2687type. The bit size of <tt>value</tt> must be larger than the bit size of
2688<tt>ty2</tt>. Equal sized types are not allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2689
2690<h5>Semantics:</h5>
2691<p>
2692The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2693and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
2694larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
2695It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2696
2697<h5>Example:</h5>
2698<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2699 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
2700 %Y = trunc i32 123 to bool <i>; yields bool:true</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2701</pre>
2702</div>
2703
2704<!-- _______________________________________________________________________ -->
2705<div class="doc_subsubsection">
2706 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
2707</div>
2708<div class="doc_text">
2709
2710<h5>Syntax:</h5>
2711<pre>
2712 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2713</pre>
2714
2715<h5>Overview:</h5>
2716<p>The '<tt>zext</tt>' instruction zero extends its operand to type
2717<tt>ty2</tt>.</p>
2718
2719
2720<h5>Arguments:</h5>
2721<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
2722<a href="#t_integral">integral</a> type, and a type to cast it to, which must
2723also be of <a href="#t_integral">integral</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2724<tt>value</tt> must be smaller than the bit size of the destination type,
2725<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2726
2727<h5>Semantics:</h5>
2728<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
2729bits until it reaches the size of the destination type, <tt>ty2</tt>. When the
2730the operand and the type are the same size, no bit filling is done and the
2731cast is considered a <i>no-op cast</i> because no bits change (only the type
2732changes).</p>
2733
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2734<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]2735
2736<h5>Example:</h5>
2737<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2738 %X = zext i32 257 to i64 <i>; yields i64:257</i>
2739 %Y = zext bool true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2740</pre>
2741</div>
2742
2743<!-- _______________________________________________________________________ -->
2744<div class="doc_subsubsection">
2745 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
2746</div>
2747<div class="doc_text">
2748
2749<h5>Syntax:</h5>
2750<pre>
2751 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2752</pre>
2753
2754<h5>Overview:</h5>
2755<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
2756
2757<h5>Arguments:</h5>
2758<p>
2759The '<tt>sext</tt>' instruction takes a value to cast, which must be of
2760<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]2761also be of <a href="#t_integral">integral</a> type. The bit size of the
2762<tt>value</tt> must be smaller than the bit size of the destination type,
2763<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2764
2765<h5>Semantics:</h5>
2766<p>
2767The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
2768bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
2769the type <tt>ty2</tt>. When the the operand and the type are the same size,
2770no bit filling is done and the cast is considered a <i>no-op cast</i> because
2771no bits change (only the type changes).</p>
2772
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2773<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]2774
2775<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2776<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2777 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
2778 %Y = sext bool true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2779</pre>
2780</div>
2781
2782<!-- _______________________________________________________________________ -->
2783<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]2784 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
2785</div>
2786
2787<div class="doc_text">
2788
2789<h5>Syntax:</h5>
2790
2791<pre>
2792 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2793</pre>
2794
2795<h5>Overview:</h5>
2796<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
2797<tt>ty2</tt>.</p>
2798
2799
2800<h5>Arguments:</h5>
2801<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
2802 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
2803cast it to. The size of <tt>value</tt> must be larger than the size of
2804<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
2805<i>no-op cast</i>.</p>
2806
2807<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2808<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
2809<a href="#t_floating">floating point</a> type to a smaller
2810<a href="#t_floating">floating point</a> type. If the value cannot fit within
2811the destination type, <tt>ty2</tt>, then the results are undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]2812
2813<h5>Example:</h5>
2814<pre>
2815 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
2816 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
2817</pre>
2818</div>
2819
2820<!-- _______________________________________________________________________ -->
2821<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2822 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
2823</div>
2824<div class="doc_text">
2825
2826<h5>Syntax:</h5>
2827<pre>
2828 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2829</pre>
2830
2831<h5>Overview:</h5>
2832<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
2833floating point value.</p>
2834
2835<h5>Arguments:</h5>
2836<p>The '<tt>fpext</tt>' instruction takes a
2837<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2838and a <a href="#t_floating">floating point</a> type to cast it to. The source
2839type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2840
2841<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2842<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
2843<a href="t_floating">floating point</a> type to a larger
2844<a href="t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
2845used to make a <i>no-op cast</i> because it always changes bits. Use
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2846<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]2847
2848<h5>Example:</h5>
2849<pre>
2850 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
2851 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
2852</pre>
2853</div>
2854
2855<!-- _______________________________________________________________________ -->
2856<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2857 <a name="i_fp2uint">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2858</div>
2859<div class="doc_text">
2860
2861<h5>Syntax:</h5>
2862<pre>
2863 &lt;result&gt; = fp2uint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2864</pre>
2865
2866<h5>Overview:</h5>
2867<p>The '<tt>fp2uint</tt>' converts a floating point <tt>value</tt> to its
2868unsigned integer equivalent of type <tt>ty2</tt>.
2869</p>
2870
2871<h5>Arguments:</h5>
2872<p>The '<tt>fp2uint</tt>' instruction takes a value to cast, which must be a
2873<a href="#t_floating">floating point</a> value, and a type to cast it to, which
2874must be an <a href="#t_integral">integral</a> type.</p>
2875
2876<h5>Semantics:</h5>
2877<p> The '<tt>fp2uint</tt>' instruction converts its
2878<a href="#t_floating">floating point</a> operand into the nearest (rounding
2879towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
2880the results are undefined.</p>
2881
2882<p>When converting to bool, the conversion is done as a comparison against
2883zero. If the <tt>value</tt> was zero, the bool result will be <tt>false</tt>.
2884If the <tt>value</tt> was non-zero, the bool result will be <tt>true</tt>.</p>
2885
2886<h5>Example:</h5>
2887<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2888 %X = fp2uint double 123.0 to i32 <i>; yields i32:123</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2889 %Y = fp2uint float 1.0E+300 to bool <i>; yields bool:true</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2890 %X = fp2uint float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2891</pre>
2892</div>
2893
2894<!-- _______________________________________________________________________ -->
2895<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2896 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2897</div>
2898<div class="doc_text">
2899
2900<h5>Syntax:</h5>
2901<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2902 &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]2903</pre>
2904
2905<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2906<p>The '<tt>fptosi</tt>' instruction converts
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2907<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]2908</p>
2909
2910
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2911<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2912<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]2913<a href="#t_floating">floating point</a> value, and a type to cast it to, which
2914must also be an <a href="#t_integral">integral</a> type.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2915
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2916<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2917<p>The '<tt>fptosi</tt>' instruction converts its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2918<a href="#t_floating">floating point</a> operand into the nearest (rounding
2919towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
2920the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2921
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2922<p>When converting to bool, the conversion is done as a comparison against
2923zero. If the <tt>value</tt> was zero, the bool result will be <tt>false</tt>.
2924If 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]2925
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2926<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2927<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2928 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2929 %Y = fptosi float 1.0E-247 to bool <i>; yields bool:true</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2930 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2931</pre>
2932</div>
2933
2934<!-- _______________________________________________________________________ -->
2935<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2936 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2937</div>
2938<div class="doc_text">
2939
2940<h5>Syntax:</h5>
2941<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2942 &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]2943</pre>
2944
2945<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2946<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2947integer and converts that value to the <tt>ty2</tt> type.</p>
2948
2949
2950<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2951<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]2952<a href="#t_integral">integral</a> value, and a type to cast it to, which must
2953be a <a href="#t_floating">floating point</a> type.</p>
2954
2955<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2956<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2957integer quantity and converts it to the corresponding floating point value. If
2958the value cannot fit in the floating point value, the results are undefined.</p>
2959
2960
2961<h5>Example:</h5>
2962<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2963 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
2964 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2965</pre>
2966</div>
2967
2968<!-- _______________________________________________________________________ -->
2969<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2970 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2971</div>
2972<div class="doc_text">
2973
2974<h5>Syntax:</h5>
2975<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2976 &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]2977</pre>
2978
2979<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2980<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2981integer and converts that value to the <tt>ty2</tt> type.</p>
2982
2983<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2984<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]2985<a href="#t_integral">integral</a> value, and a type to cast it to, which must be
2986a <a href="#t_floating">floating point</a> type.</p>
2987
2988<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2989<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2990integer quantity and converts it to the corresponding floating point value. If
2991the value cannot fit in the floating point value, the results are undefined.</p>
2992
2993<h5>Example:</h5>
2994<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2995 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
2996 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2997</pre>
2998</div>
2999
3000<!-- _______________________________________________________________________ -->
3001<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3002 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3003</div>
3004<div class="doc_text">
3005
3006<h5>Syntax:</h5>
3007<pre>
3008 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3009</pre>
3010
3011<h5>Overview:</h5>
3012<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3013the integer type <tt>ty2</tt>.</p>
3014
3015<h5>Arguments:</h5>
3016<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
3017must be a <a href="t_pointer">pointer</a> value, and a type to cast it to
3018<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
3019
3020<h5>Semantics:</h5>
3021<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3022<tt>ty2</tt> by interpreting the pointer value as an integer and either
3023truncating or zero extending that value to the size of the integer type. If
3024<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3025<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
3026are the same size, then nothing is done (<i>no-op cast</i>).</p>
3027
3028<h5>Example:</h5>
3029<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3030 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit</i>
3031 %Y = ptrtoint i32* %x to i64 <i>; yields zero extend on 32-bit</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3032</pre>
3033</div>
3034
3035<!-- _______________________________________________________________________ -->
3036<div class="doc_subsubsection">
3037 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3038</div>
3039<div class="doc_text">
3040
3041<h5>Syntax:</h5>
3042<pre>
3043 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3044</pre>
3045
3046<h5>Overview:</h5>
3047<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3048a pointer type, <tt>ty2</tt>.</p>
3049
3050<h5>Arguments:</h5>
3051<p>The '<tt>inttoptr</tt>' instruction takes an <a href="i_integer">integer</a>
3052value to cast, and a type to cast it to, which must be a
3053<a href="#t_pointer">pointer</a> type. </tt>
3054
3055<h5>Semantics:</h5>
3056<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3057<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3058the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3059size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3060the size of a pointer then a zero extension is done. If they are the same size,
3061nothing is done (<i>no-op cast</i>).</p>
3062
3063<h5>Example:</h5>
3064<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3065 %X = inttoptr i32 255 to i32* <i>; yields zero extend on 64-bit</i>
3066 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit </i>
3067 %Y = inttoptr i16 0 to i32* <i>; yields zero extend on 32-bit</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3068</pre>
3069</div>
3070
3071<!-- _______________________________________________________________________ -->
3072<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3073 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3074</div>
3075<div class="doc_text">
3076
3077<h5>Syntax:</h5>
3078<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3079 &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]3080</pre>
3081
3082<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3083<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3084<tt>ty2</tt> without changing any bits.</p>
3085
3086<h5>Arguments:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3087<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3088a first class value, and a type to cast it to, which must also be a <a
3089 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
3090and the destination type, <tt>ty2</tt>, must be identical.</p>
3091
3092<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3093<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3094<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3095this conversion. The conversion is done as if the <tt>value</tt> had been
3096stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3097converted to other pointer types with this instruction. To convert pointers to
3098other types, use the <a href="#i_inttoptr">inttoptr</a> or
3099<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3100
3101<h5>Example:</h5>
3102<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3103 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
3104 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
3105 %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3106</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3107</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3108
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3109<!-- ======================================================================= -->
3110<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3111<div class="doc_text">
3112<p>The instructions in this category are the "miscellaneous"
3113instructions, which defy better classification.</p>
3114</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3115
3116<!-- _______________________________________________________________________ -->
3117<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3118</div>
3119<div class="doc_text">
3120<h5>Syntax:</h5>
3121<pre> &lt;result&gt; = icmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
3122</pre>
3123<h5>Overview:</h5>
3124<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
3125of its two integer operands.</p>
3126<h5>Arguments:</h5>
3127<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
3128the condition code which indicates the kind of comparison to perform. It is not
3129a value, just a keyword. The possibilities for the condition code are:
3130<ol>
3131 <li><tt>eq</tt>: equal</li>
3132 <li><tt>ne</tt>: not equal </li>
3133 <li><tt>ugt</tt>: unsigned greater than</li>
3134 <li><tt>uge</tt>: unsigned greater or equal</li>
3135 <li><tt>ult</tt>: unsigned less than</li>
3136 <li><tt>ule</tt>: unsigned less or equal</li>
3137 <li><tt>sgt</tt>: signed greater than</li>
3138 <li><tt>sge</tt>: signed greater or equal</li>
3139 <li><tt>slt</tt>: signed less than</li>
3140 <li><tt>sle</tt>: signed less or equal</li>
3141</ol>
3142<p>The remaining two arguments must be of <a href="#t_integral">integral</a>,
3143<a href="#t_pointer">pointer</a> or a <a href="#t_packed">packed</a> integral
3144type. They must have identical types.</p>
3145<h5>Semantics:</h5>
3146<p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3147the condition code given as <tt>cond</tt>. The comparison performed always
3148yields a <a href="#t_bool">bool</a> result, as follows:
3149<ol>
3150 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3151 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3152 </li>
3153 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3154 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3155 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3156 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3157 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3158 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3159 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3160 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3161 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3162 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3163 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3164 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3165 <li><tt>sge</tt>: interprets the operands as signed values and yields
3166 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3167 <li><tt>slt</tt>: interprets the operands as signed values and yields
3168 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3169 <li><tt>sle</tt>: interprets the operands as signed values and yields
3170 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3171 </li>
3172</ol>
3173<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
3174values are treated as integers and then compared.</p>
3175<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]3176the vector are compared in turn and the predicate must hold for all
3177elements.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3178
3179<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3180<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3181 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3182 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3183 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3184 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3185 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3186</pre>
3187</div>
3188
3189<!-- _______________________________________________________________________ -->
3190<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3191</div>
3192<div class="doc_text">
3193<h5>Syntax:</h5>
3194<pre> &lt;result&gt; = fcmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
3195</pre>
3196<h5>Overview:</h5>
3197<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3198of its floating point operands.</p>
3199<h5>Arguments:</h5>
3200<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
3201the condition code which indicates the kind of comparison to perform. It is not
3202a value, just a keyword. The possibilities for the condition code are:
3203<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3204 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3205 <li><tt>oeq</tt>: ordered and equal</li>
3206 <li><tt>ogt</tt>: ordered and greater than </li>
3207 <li><tt>oge</tt>: ordered and greater than or equal</li>
3208 <li><tt>olt</tt>: ordered and less than </li>
3209 <li><tt>ole</tt>: ordered and less than or equal</li>
3210 <li><tt>one</tt>: ordered and not equal</li>
3211 <li><tt>ord</tt>: ordered (no nans)</li>
3212 <li><tt>ueq</tt>: unordered or equal</li>
3213 <li><tt>ugt</tt>: unordered or greater than </li>
3214 <li><tt>uge</tt>: unordered or greater than or equal</li>
3215 <li><tt>ult</tt>: unordered or less than </li>
3216 <li><tt>ule</tt>: unordered or less than or equal</li>
3217 <li><tt>une</tt>: unordered or not equal</li>
3218 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3219 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3220</ol>
Reid Spencer93a49852006-12-06 07:08:07 +0000[diff] [blame]3221<p>In the preceding, <i>ordered</i> means that neither operand is a QNAN while
3222<i>unordered</i> means that either operand may be a QNAN.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3223<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be of
3224<a href="#t_floating">floating point</a>, or a <a href="#t_packed">packed</a>
3225floating point type. They must have identical types.</p>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3226<p>In the foregoing, <i>ordered</i> means that neither operand is a QNAN and
3227<i>unordered</i> means that either operand is a QNAN.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3228<h5>Semantics:</h5>
3229<p>The '<tt>fcmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3230the condition code given as <tt>cond</tt>. The comparison performed always
3231yields a <a href="#t_bool">bool</a> result, as follows:
3232<ol>
3233 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3234 <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]3235 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3236 <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]3237 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3238 <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]3239 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3240 <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]3241 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3242 <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]3243 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3244 <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]3245 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3246 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3247 <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]3248 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3249 <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]3250 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3251 <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]3252 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3253 <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]3254 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3255 <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]3256 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3257 <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]3258 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3259 <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]3260 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3261</ol>
3262<p>If the operands are <a href="#t_packed">packed</a> typed, the elements of
3263the vector are compared in turn and the predicate must hold for all elements.
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3264</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3265
3266<h5>Example:</h5>
3267<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3268 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3269 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3270 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3271</pre>
3272</div>
3273
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3274<!-- _______________________________________________________________________ -->
3275<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
3276Instruction</a> </div>
3277<div class="doc_text">
3278<h5>Syntax:</h5>
3279<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
3280<h5>Overview:</h5>
3281<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
3282the SSA graph representing the function.</p>
3283<h5>Arguments:</h5>
3284<p>The type of the incoming values are specified with the first type
3285field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
3286as arguments, with one pair for each predecessor basic block of the
3287current block. Only values of <a href="#t_firstclass">first class</a>
3288type may be used as the value arguments to the PHI node. Only labels
3289may be used as the label arguments.</p>
3290<p>There must be no non-phi instructions between the start of a basic
3291block and the PHI instructions: i.e. PHI instructions must be first in
3292a basic block.</p>
3293<h5>Semantics:</h5>
3294<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the
3295value specified by the parameter, depending on which basic block we
3296came from in the last <a href="#terminators">terminator</a> instruction.</p>
3297<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3298<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]3299</div>
3300
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3301<!-- _______________________________________________________________________ -->
3302<div class="doc_subsubsection">
3303 <a name="i_select">'<tt>select</tt>' Instruction</a>
3304</div>
3305
3306<div class="doc_text">
3307
3308<h5>Syntax:</h5>
3309
3310<pre>
3311 &lt;result&gt; = select bool &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
3312</pre>
3313
3314<h5>Overview:</h5>
3315
3316<p>
3317The '<tt>select</tt>' instruction is used to choose one value based on a
3318condition, without branching.
3319</p>
3320
3321
3322<h5>Arguments:</h5>
3323
3324<p>
3325The '<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.
3326</p>
3327
3328<h5>Semantics:</h5>
3329
3330<p>
3331If the boolean condition evaluates to true, the instruction returns the first
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3332value argument; otherwise, it returns the second value argument.
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3333</p>
3334
3335<h5>Example:</h5>
3336
3337<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3338 %X = select bool true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3339</pre>
3340</div>
3341
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]3342
3343<!-- _______________________________________________________________________ -->
3344<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3345 <a name="i_call">'<tt>call</tt>' Instruction</a>
3346</div>
3347
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3348<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3349
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3350<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3351<pre>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3352 &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]3353</pre>
3354
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3355<h5>Overview:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3356
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3357<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3358
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3359<h5>Arguments:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3360
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3361<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3362
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3363<ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3364 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3365 <p>The optional "tail" marker indicates whether the callee function accesses
3366 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3367 function call is eligible for tail call optimization. Note that calls may
3368 be marked "tail" even if they do not occur before a <a
3369 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3370 </li>
3371 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3372 <p>The optional "cconv" marker indicates which <a href="callingconv">calling
3373 convention</a> the call should use. If none is specified, the call defaults
3374 to using C calling conventions.
3375 </li>
3376 <li>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3377 <p>'<tt>ty</tt>': shall be the signature of the pointer to function value
3378 being invoked. The argument types must match the types implied by this
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3379 signature. This type can be omitted if the function is not varargs and
3380 if the function type does not return a pointer to a function.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3381 </li>
3382 <li>
3383 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
3384 be invoked. In most cases, this is a direct function invocation, but
3385 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3386 to function value.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3387 </li>
3388 <li>
3389 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencera7e302a2005-05-01 22:22:57 +0000[diff] [blame]3390 function signature argument types. All arguments must be of
3391 <a href="#t_firstclass">first class</a> type. If the function signature
3392 indicates the function accepts a variable number of arguments, the extra
3393 arguments can be specified.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3394 </li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3395</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3396
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3397<h5>Semantics:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3398
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3399<p>The '<tt>call</tt>' instruction is used to cause control flow to
3400transfer to a specified function, with its incoming arguments bound to
3401the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
3402instruction in the called function, control flow continues with the
3403instruction after the function call, and the return value of the
3404function is bound to the result argument. This is a simpler case of
3405the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3406
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3407<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3408
3409<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3410 %retval = call i32 %test(i32 %argc)
3411 call i32(i8 *, ...) *%printf(i8 * %msg, i32 12, i8 42);
3412 %X = tail call i32 %foo()
3413 %Y = tail call <a href="#callingconv">fastcc</a> i32 %foo()
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3414</pre>
3415
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3416</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3417
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3418<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3419<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3420 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3421</div>
3422
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3423<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3424
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3425<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3426
3427<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3428 &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]3429</pre>
3430
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3431<h5>Overview:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3432
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3433<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3434the "variable argument" area of a function call. It is used to implement the
3435<tt>va_arg</tt> macro in C.</p>
3436
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3437<h5>Arguments:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3438
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3439<p>This instruction takes a <tt>va_list*</tt> value and the type of
3440the argument. It returns a value of the specified argument type and
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]3441increments the <tt>va_list</tt> to point to the next argument. Again, the
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3442actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3443
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3444<h5>Semantics:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3445
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3446<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
3447type from the specified <tt>va_list</tt> and causes the
3448<tt>va_list</tt> to point to the next argument. For more information,
3449see the variable argument handling <a href="#int_varargs">Intrinsic
3450Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3451
3452<p>It is legal for this instruction to be called in a function which does not
3453take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3454function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3455
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3456<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3457href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3458argument.</p>
3459
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3460<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3461
3462<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
3463
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3464</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3465
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3466<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3467<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
3468<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3469
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3470<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3471
3472<p>LLVM supports the notion of an "intrinsic function". These functions have
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3473well known names and semantics and are required to follow certain
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3474restrictions. Overall, these instructions represent an extension mechanism for
3475the LLVM language that does not require changing all of the transformations in
3476LLVM to add to the language (or the bytecode reader/writer, the parser,
3477etc...).</p>
3478
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3479<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
3480prefix is reserved in LLVM for intrinsic names; thus, functions may not be named
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3481this. Intrinsic functions must always be external functions: you cannot define
3482the body of intrinsic functions. Intrinsic functions may only be used in call
3483or invoke instructions: it is illegal to take the address of an intrinsic
3484function. Additionally, because intrinsic functions are part of the LLVM
3485language, it is required that they all be documented here if any are added.</p>
3486
3487
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3488<p>To learn how to add an intrinsic function, please see the <a
Chris Lattner590cff32005-05-11 03:35:57 +0000[diff] [blame]3489href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3490</p>
3491
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3492</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3493
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3494<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3495<div class="doc_subsection">
3496 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
3497</div>
3498
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3499<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3500
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3501<p>Variable argument support is defined in LLVM with the <a
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3502 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3503intrinsic functions. These functions are related to the similarly
3504named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3505
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3506<p>All of these functions operate on arguments that use a
3507target-specific value type "<tt>va_list</tt>". The LLVM assembly
3508language reference manual does not define what this type is, so all
3509transformations should be prepared to handle intrinsics with any type
3510used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3511
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]3512<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]3513instruction and the variable argument handling intrinsic functions are
3514used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3515
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3516<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3517define i32 %test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3518 ; Initialize variable argument processing
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3519 %ap = alloca i8 *
3520 call void %<a href="#i_va_start">llvm.va_start</a>(i8 ** %ap)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3521
3522 ; Read a single integer argument
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3523 %tmp = va_arg i8 ** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3524
3525 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3526 %aq = alloca i8 *
3527 call void %<a href="#i_va_copy">llvm.va_copy</a>(i8 ** %aq, i8 ** %ap)
3528 call void %<a href="#i_va_end">llvm.va_end</a>(i8 ** %aq)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3529
3530 ; Stop processing of arguments.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3531 call void %<a href="#i_va_end">llvm.va_end</a>(i8 ** %ap)
3532 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3533}
3534</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3535</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3536
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3537<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3538<div class="doc_subsubsection">
3539 <a name="i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
3540</div>
3541
3542
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3543<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3544<h5>Syntax:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3545<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]3546<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3547<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
3548<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
3549href="#i_va_arg">va_arg</a></tt>.</p>
3550
3551<h5>Arguments:</h5>
3552
3553<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
3554
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3555<h5>Semantics:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3556
3557<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
3558macro available in C. In a target-dependent way, it initializes the
3559<tt>va_list</tt> element the argument points to, so that the next call to
3560<tt>va_arg</tt> will produce the first variable argument passed to the function.
3561Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
3562last argument of the function, the compiler can figure that out.</p>
3563
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3564</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3565
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3566<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3567<div class="doc_subsubsection">
3568 <a name="i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
3569</div>
3570
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3571<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3572<h5>Syntax:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3573<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]3574<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3575<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>&lt;arglist&gt;</tt>
3576which has been initialized previously with <tt><a href="#i_va_start">llvm.va_start</a></tt>
3577or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3578<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3579<p>The argument is a <tt>va_list</tt> to destroy.</p>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3580<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3581<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]3582macro available in C. In a target-dependent way, it destroys the <tt>va_list</tt>.
3583Calls to <a href="#i_va_start"><tt>llvm.va_start</tt></a> and <a
3584 href="#i_va_copy"><tt>llvm.va_copy</tt></a> must be matched exactly
3585with calls to <tt>llvm.va_end</tt>.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3586</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3587
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3588<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3589<div class="doc_subsubsection">
3590 <a name="i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
3591</div>
3592
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3593<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3594
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3595<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3596
3597<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3598 declare void %llvm.va_copy(&lt;va_list&gt;* &lt;destarglist&gt;,
Andrew Lenharthd0a4c622005-06-22 20:38:11 +0000[diff] [blame]3599 &lt;va_list&gt;* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3600</pre>
3601
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3602<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3603
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3604<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position from
3605the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3606
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3607<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3608
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3609<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]3610The 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]3611
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3612
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3613<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3614
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3615<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt> macro
3616available in C. In a target-dependent way, it copies the source
3617<tt>va_list</tt> element into the destination list. This intrinsic is necessary
3618because 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]3619arbitrarily complex and require memory allocation, for example.</p>
3620
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3621</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3622
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3623<!-- ======================================================================= -->
3624<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3625 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
3626</div>
3627
3628<div class="doc_text">
3629
3630<p>
3631LLVM support for <a href="GarbageCollection.html">Accurate Garbage
3632Collection</a> requires the implementation and generation of these intrinsics.
3633These intrinsics allow identification of <a href="#i_gcroot">GC roots on the
3634stack</a>, as well as garbage collector implementations that require <a
3635href="#i_gcread">read</a> and <a href="#i_gcwrite">write</a> barriers.
3636Front-ends for type-safe garbage collected languages should generate these
3637intrinsics to make use of the LLVM garbage collectors. For more details, see <a
3638href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
3639</p>
3640</div>
3641
3642<!-- _______________________________________________________________________ -->
3643<div class="doc_subsubsection">
3644 <a name="i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
3645</div>
3646
3647<div class="doc_text">
3648
3649<h5>Syntax:</h5>
3650
3651<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]3652 declare void %llvm.gcroot(&lt;ty&gt;** %ptrloc, &lt;ty2&gt;* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3653</pre>
3654
3655<h5>Overview:</h5>
3656
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]3657<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]3658the code generator, and allows some metadata to be associated with it.</p>
3659
3660<h5>Arguments:</h5>
3661
3662<p>The first argument specifies the address of a stack object that contains the
3663root pointer. The second pointer (which must be either a constant or a global
3664value address) contains the meta-data to be associated with the root.</p>
3665
3666<h5>Semantics:</h5>
3667
3668<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
3669location. At compile-time, the code generator generates information to allow
3670the runtime to find the pointer at GC safe points.
3671</p>
3672
3673</div>
3674
3675
3676<!-- _______________________________________________________________________ -->
3677<div class="doc_subsubsection">
3678 <a name="i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
3679</div>
3680
3681<div class="doc_text">
3682
3683<h5>Syntax:</h5>
3684
3685<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3686 declare i8 * %llvm.gcread(i8 * %ObjPtr, i8 ** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3687</pre>
3688
3689<h5>Overview:</h5>
3690
3691<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
3692locations, allowing garbage collector implementations that require read
3693barriers.</p>
3694
3695<h5>Arguments:</h5>
3696
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3697<p>The second argument is the address to read from, which should be an address
3698allocated from the garbage collector. The first object is a pointer to the
3699start of the referenced object, if needed by the language runtime (otherwise
3700null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3701
3702<h5>Semantics:</h5>
3703
3704<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
3705instruction, but may be replaced with substantially more complex code by the
3706garbage collector runtime, as needed.</p>
3707
3708</div>
3709
3710
3711<!-- _______________________________________________________________________ -->
3712<div class="doc_subsubsection">
3713 <a name="i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
3714</div>
3715
3716<div class="doc_text">
3717
3718<h5>Syntax:</h5>
3719
3720<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3721 declare void %llvm.gcwrite(i8 * %P1, i8 * %Obj, i8 ** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3722</pre>
3723
3724<h5>Overview:</h5>
3725
3726<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
3727locations, allowing garbage collector implementations that require write
3728barriers (such as generational or reference counting collectors).</p>
3729
3730<h5>Arguments:</h5>
3731
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3732<p>The first argument is the reference to store, the second is the start of the
3733object to store it to, and the third is the address of the field of Obj to
3734store to. If the runtime does not require a pointer to the object, Obj may be
3735null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3736
3737<h5>Semantics:</h5>
3738
3739<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
3740instruction, but may be replaced with substantially more complex code by the
3741garbage collector runtime, as needed.</p>
3742
3743</div>
3744
3745
3746
3747<!-- ======================================================================= -->
3748<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3749 <a name="int_codegen">Code Generator Intrinsics</a>
3750</div>
3751
3752<div class="doc_text">
3753<p>
3754These intrinsics are provided by LLVM to expose special features that may only
3755be implemented with code generator support.
3756</p>
3757
3758</div>
3759
3760<!-- _______________________________________________________________________ -->
3761<div class="doc_subsubsection">
3762 <a name="i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
3763</div>
3764
3765<div class="doc_text">
3766
3767<h5>Syntax:</h5>
3768<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3769 declare i8 *%llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3770</pre>
3771
3772<h5>Overview:</h5>
3773
3774<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]3775The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
3776target-specific value indicating the return address of the current function
3777or one of its callers.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3778</p>
3779
3780<h5>Arguments:</h5>
3781
3782<p>
3783The argument to this intrinsic indicates which function to return the address
3784for. Zero indicates the calling function, one indicates its caller, etc. The
3785argument is <b>required</b> to be a constant integer value.
3786</p>
3787
3788<h5>Semantics:</h5>
3789
3790<p>
3791The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
3792the return address of the specified call frame, or zero if it cannot be
3793identified. The value returned by this intrinsic is likely to be incorrect or 0
3794for arguments other than zero, so it should only be used for debugging purposes.
3795</p>
3796
3797<p>
3798Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]3799aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3800source-language caller.
3801</p>
3802</div>
3803
3804
3805<!-- _______________________________________________________________________ -->
3806<div class="doc_subsubsection">
3807 <a name="i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
3808</div>
3809
3810<div class="doc_text">
3811
3812<h5>Syntax:</h5>
3813<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3814 declare i8 *%llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3815</pre>
3816
3817<h5>Overview:</h5>
3818
3819<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]3820The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
3821target-specific frame pointer value for the specified stack frame.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3822</p>
3823
3824<h5>Arguments:</h5>
3825
3826<p>
3827The argument to this intrinsic indicates which function to return the frame
3828pointer for. Zero indicates the calling function, one indicates its caller,
3829etc. The argument is <b>required</b> to be a constant integer value.
3830</p>
3831
3832<h5>Semantics:</h5>
3833
3834<p>
3835The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
3836the frame address of the specified call frame, or zero if it cannot be
3837identified. The value returned by this intrinsic is likely to be incorrect or 0
3838for arguments other than zero, so it should only be used for debugging purposes.
3839</p>
3840
3841<p>
3842Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]3843aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3844source-language caller.
3845</p>
3846</div>
3847
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3848<!-- _______________________________________________________________________ -->
3849<div class="doc_subsubsection">
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]3850 <a name="i_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
3851</div>
3852
3853<div class="doc_text">
3854
3855<h5>Syntax:</h5>
3856<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3857 declare i8 *%llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]3858</pre>
3859
3860<h5>Overview:</h5>
3861
3862<p>
3863The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
3864the function stack, for use with <a href="#i_stackrestore">
3865<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
3866features like scoped automatic variable sized arrays in C99.
3867</p>
3868
3869<h5>Semantics:</h5>
3870
3871<p>
3872This intrinsic returns a opaque pointer value that can be passed to <a
3873href="#i_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
3874<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
3875<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
3876state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
3877practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
3878that were allocated after the <tt>llvm.stacksave</tt> was executed.
3879</p>
3880
3881</div>
3882
3883<!-- _______________________________________________________________________ -->
3884<div class="doc_subsubsection">
3885 <a name="i_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
3886</div>
3887
3888<div class="doc_text">
3889
3890<h5>Syntax:</h5>
3891<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3892 declare void %llvm.stackrestore(i8 * %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]3893</pre>
3894
3895<h5>Overview:</h5>
3896
3897<p>
3898The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
3899the function stack to the state it was in when the corresponding <a
3900href="#llvm.stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
3901useful for implementing language features like scoped automatic variable sized
3902arrays in C99.
3903</p>
3904
3905<h5>Semantics:</h5>
3906
3907<p>
3908See the description for <a href="#i_stacksave"><tt>llvm.stacksave</tt></a>.
3909</p>
3910
3911</div>
3912
3913
3914<!-- _______________________________________________________________________ -->
3915<div class="doc_subsubsection">
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3916 <a name="i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
3917</div>
3918
3919<div class="doc_text">
3920
3921<h5>Syntax:</h5>
3922<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3923 declare void %llvm.prefetch(i8 * &lt;address&gt;,
3924 i32 &lt;rw&gt;, i32 &lt;locality&gt;)
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3925</pre>
3926
3927<h5>Overview:</h5>
3928
3929
3930<p>
3931The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3932a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
3933no
3934effect on the behavior of the program but can change its performance
Chris Lattner2a615362005-02-28 19:47:14 +0000[diff] [blame]3935characteristics.
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3936</p>
3937
3938<h5>Arguments:</h5>
3939
3940<p>
3941<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
3942determining if the fetch should be for a read (0) or write (1), and
3943<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattneraeffb4a2005-03-07 20:31:38 +0000[diff] [blame]3944locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3945<tt>locality</tt> arguments must be constant integers.
3946</p>
3947
3948<h5>Semantics:</h5>
3949
3950<p>
3951This intrinsic does not modify the behavior of the program. In particular,
3952prefetches cannot trap and do not produce a value. On targets that support this
3953intrinsic, the prefetch can provide hints to the processor cache for better
3954performance.
3955</p>
3956
3957</div>
3958
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]3959<!-- _______________________________________________________________________ -->
3960<div class="doc_subsubsection">
3961 <a name="i_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
3962</div>
3963
3964<div class="doc_text">
3965
3966<h5>Syntax:</h5>
3967<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3968 declare void %llvm.pcmarker( i32 &lt;id&gt; )
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]3969</pre>
3970
3971<h5>Overview:</h5>
3972
3973
3974<p>
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3975The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
3976(PC) in a region of
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]3977code to simulators and other tools. The method is target specific, but it is
3978expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]3979The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnerd07c3f42005-11-15 06:07:55 +0000[diff] [blame]3980after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb3e7afd2006-03-24 07:16:10 +0000[diff] [blame]3981optimizations. The intended use is to be inserted after optimizations to allow
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3982correlations of simulation runs.
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]3983</p>
3984
3985<h5>Arguments:</h5>
3986
3987<p>
3988<tt>id</tt> is a numerical id identifying the marker.
3989</p>
3990
3991<h5>Semantics:</h5>
3992
3993<p>
3994This intrinsic does not modify the behavior of the program. Backends that do not
3995support this intrinisic may ignore it.
3996</p>
3997
3998</div>
3999
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4000<!-- _______________________________________________________________________ -->
4001<div class="doc_subsubsection">
4002 <a name="i_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
4003</div>
4004
4005<div class="doc_text">
4006
4007<h5>Syntax:</h5>
4008<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4009 declare i64 %llvm.readcyclecounter( )
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4010</pre>
4011
4012<h5>Overview:</h5>
4013
4014
4015<p>
4016The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
4017counter register (or similar low latency, high accuracy clocks) on those targets
4018that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
4019As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
4020should only be used for small timings.
4021</p>
4022
4023<h5>Semantics:</h5>
4024
4025<p>
4026When directly supported, reading the cycle counter should not modify any memory.
4027Implementations are allowed to either return a application specific value or a
4028system wide value. On backends without support, this is lowered to a constant 0.
4029</p>
4030
4031</div>
4032
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4033<!-- ======================================================================= -->
4034<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4035 <a name="int_libc">Standard C Library Intrinsics</a>
4036</div>
4037
4038<div class="doc_text">
4039<p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4040LLVM provides intrinsics for a few important standard C library functions.
4041These intrinsics allow source-language front-ends to pass information about the
4042alignment of the pointer arguments to the code generator, providing opportunity
4043for more efficient code generation.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4044</p>
4045
4046</div>
4047
4048<!-- _______________________________________________________________________ -->
4049<div class="doc_subsubsection">
4050 <a name="i_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
4051</div>
4052
4053<div class="doc_text">
4054
4055<h5>Syntax:</h5>
4056<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4057 declare void %llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4058 i32 &lt;len&gt;, i32 &lt;align&gt;)
4059 declare void %llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4060 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4061</pre>
4062
4063<h5>Overview:</h5>
4064
4065<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4066The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4067location to the destination location.
4068</p>
4069
4070<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4071Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4072intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4073</p>
4074
4075<h5>Arguments:</h5>
4076
4077<p>
4078The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4079the source. The third argument is an integer argument
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4080specifying the number of bytes to copy, and the fourth argument is the alignment
4081of the source and destination locations.
4082</p>
4083
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4084<p>
4085If 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]4086the caller guarantees that both the source and destination pointers are aligned
4087to that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4088</p>
4089
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4090<h5>Semantics:</h5>
4091
4092<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4093The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4094location to the destination location, which are not allowed to overlap. It
4095copies "len" bytes of memory over. If the argument is known to be aligned to
4096some boundary, this can be specified as the fourth argument, otherwise it should
4097be set to 0 or 1.
4098</p>
4099</div>
4100
4101
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4102<!-- _______________________________________________________________________ -->
4103<div class="doc_subsubsection">
4104 <a name="i_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
4105</div>
4106
4107<div class="doc_text">
4108
4109<h5>Syntax:</h5>
4110<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4111 declare void %llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4112 i32 &lt;len&gt;, i32 &lt;align&gt;)
4113 declare void %llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4114 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4115</pre>
4116
4117<h5>Overview:</h5>
4118
4119<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4120The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
4121location to the destination location. It is similar to the
4122'<tt>llvm.memcmp</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4123</p>
4124
4125<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4126Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
4127intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4128</p>
4129
4130<h5>Arguments:</h5>
4131
4132<p>
4133The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4134the source. The third argument is an integer argument
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4135specifying the number of bytes to copy, and the fourth argument is the alignment
4136of the source and destination locations.
4137</p>
4138
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4139<p>
4140If 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]4141the caller guarantees that the source and destination pointers are aligned to
4142that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4143</p>
4144
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4145<h5>Semantics:</h5>
4146
4147<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4148The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4149location to the destination location, which may overlap. It
4150copies "len" bytes of memory over. If the argument is known to be aligned to
4151some boundary, this can be specified as the fourth argument, otherwise it should
4152be set to 0 or 1.
4153</p>
4154</div>
4155
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4156
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4157<!-- _______________________________________________________________________ -->
4158<div class="doc_subsubsection">
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4159 <a name="i_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4160</div>
4161
4162<div class="doc_text">
4163
4164<h5>Syntax:</h5>
4165<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4166 declare void %llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
4167 i32 &lt;len&gt;, i32 &lt;align&gt;)
4168 declare void %llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
4169 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4170</pre>
4171
4172<h5>Overview:</h5>
4173
4174<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4175The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4176byte value.
4177</p>
4178
4179<p>
4180Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
4181does not return a value, and takes an extra alignment argument.
4182</p>
4183
4184<h5>Arguments:</h5>
4185
4186<p>
4187The first argument is a pointer to the destination to fill, the second is the
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4188byte value to fill it with, the third argument is an integer
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4189argument specifying the number of bytes to fill, and the fourth argument is the
4190known alignment of destination location.
4191</p>
4192
4193<p>
4194If 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]4195the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4196</p>
4197
4198<h5>Semantics:</h5>
4199
4200<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4201The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
4202the
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4203destination location. If the argument is known to be aligned to some boundary,
4204this can be specified as the fourth argument, otherwise it should be set to 0 or
42051.
4206</p>
4207</div>
4208
4209
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4210<!-- _______________________________________________________________________ -->
4211<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4212 <a name="i_isunordered">'<tt>llvm.isunordered.*</tt>' Intrinsic</a>
Alkis Evlogimenos26bbe932004-06-13 01:16:15 +0000[diff] [blame]4213</div>
4214
4215<div class="doc_text">
4216
4217<h5>Syntax:</h5>
4218<pre>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4219 declare bool %llvm.isunordered.f32(float Val1, float Val2)
4220 declare bool %llvm.isunordered.f64(double Val1, double Val2)
Alkis Evlogimenos26bbe932004-06-13 01:16:15 +0000[diff] [blame]4221</pre>
4222
4223<h5>Overview:</h5>
4224
4225<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4226The '<tt>llvm.isunordered</tt>' intrinsics return true if either or both of the
Alkis Evlogimenos26bbe932004-06-13 01:16:15 +0000[diff] [blame]4227specified floating point values is a NAN.
4228</p>
4229
4230<h5>Arguments:</h5>
4231
4232<p>
4233The arguments are floating point numbers of the same type.
4234</p>
4235
4236<h5>Semantics:</h5>
4237
4238<p>
4239If either or both of the arguments is a SNAN or QNAN, it returns true, otherwise
4240false.
4241</p>
4242</div>
4243
4244
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4245<!-- _______________________________________________________________________ -->
4246<div class="doc_subsubsection">
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4247 <a name="i_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4248</div>
4249
4250<div class="doc_text">
4251
4252<h5>Syntax:</h5>
4253<pre>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4254 declare float %llvm.sqrt.f32(float %Val)
4255 declare double %llvm.sqrt.f64(double %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4256</pre>
4257
4258<h5>Overview:</h5>
4259
4260<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4261The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4262returning the same value as the libm '<tt>sqrt</tt>' function would. Unlike
4263<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
4264negative numbers (which allows for better optimization).
4265</p>
4266
4267<h5>Arguments:</h5>
4268
4269<p>
4270The argument and return value are floating point numbers of the same type.
4271</p>
4272
4273<h5>Semantics:</h5>
4274
4275<p>
4276This function returns the sqrt of the specified operand if it is a positive
4277floating point number.
4278</p>
4279</div>
4280
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4281<!-- _______________________________________________________________________ -->
4282<div class="doc_subsubsection">
4283 <a name="i_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
4284</div>
4285
4286<div class="doc_text">
4287
4288<h5>Syntax:</h5>
4289<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4290 declare float %llvm.powi.f32(float %Val, i32 %power)
4291 declare double %llvm.powi.f64(double %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4292</pre>
4293
4294<h5>Overview:</h5>
4295
4296<p>
4297The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
4298specified (positive or negative) power. The order of evaluation of
4299multiplications is not defined.
4300</p>
4301
4302<h5>Arguments:</h5>
4303
4304<p>
4305The second argument is an integer power, and the first is a value to raise to
4306that power.
4307</p>
4308
4309<h5>Semantics:</h5>
4310
4311<p>
4312This function returns the first value raised to the second power with an
4313unspecified sequence of rounding operations.</p>
4314</div>
4315
4316
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4317<!-- ======================================================================= -->
4318<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4319 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4320</div>
4321
4322<div class="doc_text">
4323<p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4324LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4325These allow efficient code generation for some algorithms.
4326</p>
4327
4328</div>
4329
4330<!-- _______________________________________________________________________ -->
4331<div class="doc_subsubsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4332 <a name="i_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
4333</div>
4334
4335<div class="doc_text">
4336
4337<h5>Syntax:</h5>
4338<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4339 declare i16 %llvm.bswap.i16(i16 &lt;id&gt;)
4340 declare i32 %llvm.bswap.i32(i32 &lt;id&gt;)
4341 declare i64 %llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4342</pre>
4343
4344<h5>Overview:</h5>
4345
4346<p>
4347The '<tt>llvm.bwsap</tt>' family of intrinsics is used to byteswap a 16, 32 or
434864 bit quantity. These are useful for performing operations on data that is not
4349in the target's native byte order.
4350</p>
4351
4352<h5>Semantics:</h5>
4353
4354<p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4355The <tt>llvm.bswap.16</tt> intrinsic returns an i16 value that has the high
4356and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
4357intrinsic returns an i32 value that has the four bytes of the input i32
4358swapped, so that if the input bytes are numbered 0, 1, 2, 3 then the returned
4359i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i64</tt>
4360intrinsic extends this concept to 64 bits.
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4361</p>
4362
4363</div>
4364
4365<!-- _______________________________________________________________________ -->
4366<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4367 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4368</div>
4369
4370<div class="doc_text">
4371
4372<h5>Syntax:</h5>
4373<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4374 declare i8 %llvm.ctpop.i8 (i8 &lt;src&gt;)
4375 declare i16 %llvm.ctpop.i16(i16 &lt;src&gt;)
4376 declare i32 %llvm.ctpop.i32(i32 &lt;src&gt;)
4377 declare i64 %llvm.ctpop.i64(i64 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4378</pre>
4379
4380<h5>Overview:</h5>
4381
4382<p>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4383The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
4384value.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4385</p>
4386
4387<h5>Arguments:</h5>
4388
4389<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]4390The only argument is the value to be counted. The argument may be of any
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4391unsigned integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4392</p>
4393
4394<h5>Semantics:</h5>
4395
4396<p>
4397The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
4398</p>
4399</div>
4400
4401<!-- _______________________________________________________________________ -->
4402<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]4403 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4404</div>
4405
4406<div class="doc_text">
4407
4408<h5>Syntax:</h5>
4409<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4410 declare i8 %llvm.ctlz.i8 (i8 &lt;src&gt;)
4411 declare i16 %llvm.ctlz.i16(i16 &lt;src&gt;)
4412 declare i32 %llvm.ctlz.i32(i32 &lt;src&gt;)
4413 declare i64 %llvm.ctlz.i64(i64 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4414</pre>
4415
4416<h5>Overview:</h5>
4417
4418<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4419The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
4420leading zeros in a variable.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4421</p>
4422
4423<h5>Arguments:</h5>
4424
4425<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]4426The only argument is the value to be counted. The argument may be of any
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4427unsigned integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4428</p>
4429
4430<h5>Semantics:</h5>
4431
4432<p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4433The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
4434in 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]4435of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4436</p>
4437</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4438
4439
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4440
4441<!-- _______________________________________________________________________ -->
4442<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]4443 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4444</div>
4445
4446<div class="doc_text">
4447
4448<h5>Syntax:</h5>
4449<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4450 declare i8 %llvm.cttz.i8 (i8 &lt;src&gt;)
4451 declare i16 %llvm.cttz.i16(i16 &lt;src&gt;)
4452 declare i32 %llvm.cttz.i32(i32 &lt;src&gt;)
4453 declare i64 %llvm.cttz.i64(i64 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4454</pre>
4455
4456<h5>Overview:</h5>
4457
4458<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4459The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
4460trailing zeros.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4461</p>
4462
4463<h5>Arguments:</h5>
4464
4465<p>
4466The only argument is the value to be counted. The argument may be of any
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4467unsigned integer type. The return type must match the argument type.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4468</p>
4469
4470<h5>Semantics:</h5>
4471
4472<p>
4473The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
4474in a variable. If the src == 0 then the result is the size in bits of the type
4475of src. For example, <tt>llvm.cttz(2) = 1</tt>.
4476</p>
4477</div>
4478
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4479<!-- ======================================================================= -->
4480<div class="doc_subsection">
4481 <a name="int_debugger">Debugger Intrinsics</a>
4482</div>
4483
4484<div class="doc_text">
4485<p>
4486The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
4487are described in the <a
4488href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
4489Debugging</a> document.
4490</p>
4491</div>
4492
4493
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4494<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4495<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]4496<address>
4497 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
4498 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
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4500 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!" /></a>
4501
4502 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]4503 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]4504 Last modified: $Date$
4505</address>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4506</body>
4507</html>