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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 5cf0fe40d0632fb130ca81f7efa32fa988de3c79 / . / 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
Reid Spencerac8d2762007-01-05 00:59:10 +0000[diff] [blame]498outside of the current module.</p>
499<p>It is illegal for a function <i>declaration</i>
500to have any linkage type other than "externally visible", <tt>dllimport</tt>,
501or <tt>extern_weak</tt>.</a></p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]502
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]503</div>
504
505<!-- ======================================================================= -->
506<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]507 <a name="callingconv">Calling Conventions</a>
508</div>
509
510<div class="doc_text">
511
512<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
513and <a href="#i_invoke">invokes</a> can all have an optional calling convention
514specified for the call. The calling convention of any pair of dynamic
515caller/callee must match, or the behavior of the program is undefined. The
516following calling conventions are supported by LLVM, and more may be added in
517the future:</p>
518
519<dl>
520 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
521
522 <dd>This calling convention (the default if no other calling convention is
523 specified) matches the target C calling conventions. This calling convention
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]524 supports varargs function calls and tolerates some mismatch in the declared
Reid Spencerc28d2bc2006-12-31 21:30:18 +0000[diff] [blame]525 prototype and implemented declaration of the function (as does normal C).
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]526 </dd>
527
Chris Lattner5710ce92006-05-19 21:15:36 +0000[diff] [blame]528 <dt><b>"<tt>csretcc</tt>" - The C struct return calling convention</b>:</dt>
529
530 <dd>This calling convention matches the target C calling conventions, except
531 that functions with this convention are required to take a pointer as their
532 first argument, and the return type of the function must be void. This is
533 used for C functions that return aggregates by-value. In this case, the
534 function has been transformed to take a pointer to the struct as the first
535 argument to the function. For targets where the ABI specifies specific
536 behavior for structure-return calls, the calling convention can be used to
537 distinguish between struct return functions and other functions that take a
538 pointer to a struct as the first argument.
539 </dd>
540
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]541 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
542
543 <dd>This calling convention attempts to make calls as fast as possible
544 (e.g. by passing things in registers). This calling convention allows the
545 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner8cdc5bc2005-05-06 23:08:23 +0000[diff] [blame]546 without having to conform to an externally specified ABI. Implementations of
547 this convention should allow arbitrary tail call optimization to be supported.
548 This calling convention does not support varargs and requires the prototype of
549 all callees to exactly match the prototype of the function definition.
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]550 </dd>
551
552 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
553
554 <dd>This calling convention attempts to make code in the caller as efficient
555 as possible under the assumption that the call is not commonly executed. As
556 such, these calls often preserve all registers so that the call does not break
557 any live ranges in the caller side. This calling convention does not support
558 varargs and requires the prototype of all callees to exactly match the
559 prototype of the function definition.
560 </dd>
561
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]562 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]563
564 <dd>Any calling convention may be specified by number, allowing
565 target-specific calling conventions to be used. Target specific calling
566 conventions start at 64.
567 </dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]568</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]569
570<p>More calling conventions can be added/defined on an as-needed basis, to
571support pascal conventions or any other well-known target-independent
572convention.</p>
573
574</div>
575
576<!-- ======================================================================= -->
577<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]578 <a name="globalvars">Global Variables</a>
579</div>
580
581<div class="doc_text">
582
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]583<p>Global variables define regions of memory allocated at compilation time
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]584instead of run-time. Global variables may optionally be initialized, may have
585an explicit section to be placed in, and may
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]586have an optional explicit alignment specified. A
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]587variable may be defined as a global "constant," which indicates that the
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]588contents of the variable will <b>never</b> be modified (enabling better
589optimization, allowing the global data to be placed in the read-only section of
590an executable, etc). Note that variables that need runtime initialization
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]591cannot be marked "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]592
593<p>
594LLVM explicitly allows <em>declarations</em> of global variables to be marked
595constant, even if the final definition of the global is not. This capability
596can be used to enable slightly better optimization of the program, but requires
597the language definition to guarantee that optimizations based on the
598'constantness' are valid for the translation units that do not include the
599definition.
600</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]601
602<p>As SSA values, global variables define pointer values that are in
603scope (i.e. they dominate) all basic blocks in the program. Global
604variables always define a pointer to their "content" type because they
605describe a region of memory, and all memory objects in LLVM are
606accessed through pointers.</p>
607
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]608<p>LLVM allows an explicit section to be specified for globals. If the target
609supports it, it will emit globals to the section specified.</p>
610
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]611<p>An explicit alignment may be specified for a global. If not present, or if
612the alignment is set to zero, the alignment of the global is set by the target
613to whatever it feels convenient. If an explicit alignment is specified, the
614global is forced to have at least that much alignment. All alignments must be
615a power of 2.</p>
616
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]617</div>
618
619
620<!-- ======================================================================= -->
621<div class="doc_subsection">
622 <a name="functionstructure">Functions</a>
623</div>
624
625<div class="doc_text">
626
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]627<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
628an optional <a href="#linkage">linkage type</a>, an optional
629<a href="#callingconv">calling convention</a>, a return type, an optional
630<a href="#paramattrs">parameter attribute</a> for the return type, a function
631name, a (possibly empty) argument list (each with optional
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]632<a href="#paramattrs">parameter attributes</a>), an optional section, an
633optional alignment, an opening curly brace, a list of basic blocks, and a
634closing curly brace. LLVM function declarations
635consist of the "<tt>declare</tt>" keyword, an optional <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]636 href="#callingconv">calling convention</a>, a return type, an optional
637<a href="#paramattrs">parameter attribute</a> for the return type, a function
638name, a possibly empty list of arguments, and an optional alignment.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]639
640<p>A function definition contains a list of basic blocks, forming the CFG for
641the function. Each basic block may optionally start with a label (giving the
642basic block a symbol table entry), contains a list of instructions, and ends
643with a <a href="#terminators">terminator</a> instruction (such as a branch or
644function return).</p>
645
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]646<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]647executed on entrance to the function, and it is not allowed to have predecessor
648basic blocks (i.e. there can not be any branches to the entry block of a
649function). Because the block can have no predecessors, it also cannot have any
650<a href="#i_phi">PHI nodes</a>.</p>
651
652<p>LLVM functions are identified by their name and type signature. Hence, two
653functions with the same name but different parameter lists or return values are
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]654considered different functions, and LLVM will resolve references to each
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]655appropriately.</p>
656
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]657<p>LLVM allows an explicit section to be specified for functions. If the target
658supports it, it will emit functions to the section specified.</p>
659
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]660<p>An explicit alignment may be specified for a function. If not present, or if
661the alignment is set to zero, the alignment of the function is set by the target
662to whatever it feels convenient. If an explicit alignment is specified, the
663function is forced to have at least that much alignment. All alignments must be
664a power of 2.</p>
665
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]666</div>
667
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]668<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]669<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
670<div class="doc_text">
671 <p>The return type and each parameter of a function type may have a set of
672 <i>parameter attributes</i> associated with them. Parameter attributes are
673 used to communicate additional information about the result or parameters of
674 a function. Parameter attributes are considered to be part of the function
675 type so two functions types that differ only by the parameter attributes
676 are different function types.</p>
677
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]678 <p>Parameter attributes consist of an at sign (@) followed by either a single
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]679 keyword or a comma separate list of keywords enclosed in parentheses. For
680 example:<pre>
681 %someFunc = i16 @zext (i8 @(sext) %someParam)
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]682 %someFunc = i16 @zext (i8 @zext %someParam)</pre>
683 Note that the two function types above are unique because the parameter
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]684 has a different attribute (@sext in the first one, @zext in the second).</p>
685
686 <p>Currently, only the following parameter attributes are defined:
687 <dl>
688 <dt><tt>@zext</tt></dt>
689 <dd>This indicates that the parameter should be zero extended just before
690 a call to this function.</dd>
691 <dt><tt>@sext</tt></dt>
692 <dd>This indicates that the parameter should be sign extended just before
693 a call to this function.</dd>
694 </dl></p>
695
696 <p>The current motivation for parameter attributes is to enable the sign and
697 zero extend information necessary for the C calling convention to be passed
698 from the front end to LLVM. The <tt>@zext</tt> and <tt>@sext</tt> attributes
699 are used by the code generator to perform the required extension. However,
700 parameter attributes are an orthogonal feature to calling conventions and
701 may be used for other purposes in the future.</p>
702</div>
703
704<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]705<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]706 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]707</div>
708
709<div class="doc_text">
710<p>
711Modules may contain "module-level inline asm" blocks, which corresponds to the
712GCC "file scope inline asm" blocks. These blocks are internally concatenated by
713LLVM and treated as a single unit, but may be separated in the .ll file if
714desired. The syntax is very simple:
715</p>
716
717<div class="doc_code"><pre>
Chris Lattner52599e12006-01-24 00:37:20 +0000[diff] [blame]718 module asm "inline asm code goes here"
719 module asm "more can go here"
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]720</pre></div>
721
722<p>The strings can contain any character by escaping non-printable characters.
723 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
724 for the number.
725</p>
726
727<p>
728 The inline asm code is simply printed to the machine code .s file when
729 assembly code is generated.
730</p>
731</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]732
733
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]734<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]735<div class="doc_section"> <a name="typesystem">Type System</a> </div>
736<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]737
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]738<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]739
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]740<p>The LLVM type system is one of the most important features of the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]741intermediate representation. Being typed enables a number of
742optimizations to be performed on the IR directly, without having to do
743extra analyses on the side before the transformation. A strong type
744system makes it easier to read the generated code and enables novel
745analyses and transformations that are not feasible to perform on normal
746three address code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]747
748</div>
749
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]750<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]751<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]752<div class="doc_text">
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]753<p>The primitive types are the fundamental building blocks of the LLVM
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]754system. The current set of primitive types is as follows:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]755
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]756<table class="layout">
757 <tr class="layout">
758 <td class="left">
759 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]760 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]761 <tr><th>Type</th><th>Description</th></tr>
762 <tr><td><tt>void</tt></td><td>No value</td></tr>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]763 <tr><td><tt>i8</tt></td><td>Signless 8-bit value</td></tr>
764 <tr><td><tt>i32</tt></td><td>Signless 32-bit value</td></tr>
Misha Brukmancfa87bc2005-04-22 18:02:52 +0000[diff] [blame]765 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]766 <tr><td><tt>label</tt></td><td>Branch destination</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]767 </tbody>
768 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]769 </td>
770 <td class="right">
771 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]772 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]773 <tr><th>Type</th><th>Description</th></tr>
774 <tr><td><tt>bool</tt></td><td>True or False value</td></tr>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]775 <tr><td><tt>i16</tt></td><td>Signless 16-bit value</td></tr>
776 <tr><td><tt>i64</tt></td><td>Signless 64-bit value</td></tr>
777 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]778 </tbody>
779 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]780 </td>
781 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]782</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]783</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]784
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]785<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]786<div class="doc_subsubsection"> <a name="t_classifications">Type
787Classifications</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]788<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]789<p>These different primitive types fall into a few useful
790classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]791
792<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]793 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]794 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]795 <tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]796 <td><a name="t_integer">integer</a></td>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]797 <td><tt>i8, i16, i32, i64</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]798 </tr>
799 <tr>
800 <td><a name="t_integral">integral</a></td>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]801 <td><tt>bool, i8, i16, i32, i64</tt>
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]802 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]803 </tr>
804 <tr>
805 <td><a name="t_floating">floating point</a></td>
806 <td><tt>float, double</tt></td>
807 </tr>
808 <tr>
809 <td><a name="t_firstclass">first class</a></td>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]810 <td><tt>bool, i8, i16, i32, i64, float, double, <br/>
811 <a href="#t_pointer">pointer</a>,<a href="#t_packed">packed</a></tt>
812 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]813 </tr>
814 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]815</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]816
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]817<p>The <a href="#t_firstclass">first class</a> types are perhaps the
818most important. Values of these types are the only ones which can be
819produced by instructions, passed as arguments, or used as operands to
820instructions. This means that all structures and arrays must be
821manipulated either by pointer or by component.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]822</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]823
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]824<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]825<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]826
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]827<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]828
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]829<p>The real power in LLVM comes from the derived types in the system.
830This is what allows a programmer to represent arrays, functions,
831pointers, and other useful types. Note that these derived types may be
832recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]833
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]834</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]835
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]836<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]837<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]838
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]839<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]840
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]841<h5>Overview:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]842
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]843<p>The array type is a very simple derived type that arranges elements
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]844sequentially in memory. The array type requires a size (number of
845elements) and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]846
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]847<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]848
849<pre>
850 [&lt;# elements&gt; x &lt;elementtype&gt;]
851</pre>
852
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]853<p>The number of elements is a constant integer value; elementtype may
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]854be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]855
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]856<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]857<table class="layout">
858 <tr class="layout">
859 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]860 <tt>[40 x i32 ]</tt><br/>
861 <tt>[41 x i32 ]</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]862 <tt>[40 x i8]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]863 </td>
864 <td class="left">
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]865 Array of 40 32-bit integer values.<br/>
866 Array of 41 32-bit integer values.<br/>
867 Array of 40 8-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]868 </td>
869 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]870</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]871<p>Here are some examples of multidimensional arrays:</p>
872<table class="layout">
873 <tr class="layout">
874 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]875 <tt>[3 x [4 x i32]]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]876 <tt>[12 x [10 x float]]</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]877 <tt>[2 x [3 x [4 x i16]]]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]878 </td>
879 <td class="left">
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]880 3x4 array of 32-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]881 12x10 array of single precision floating point values.<br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]882 2x3x4 array of 16-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]883 </td>
884 </tr>
885</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]886
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]887<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
888length array. Normally, accesses past the end of an array are undefined in
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]889LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
890As a special case, however, zero length arrays are recognized to be variable
891length. This allows implementation of 'pascal style arrays' with the LLVM
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]892type "{ i32, [0 x float]}", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]893
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]894</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]895
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]896<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]897<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]898<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]899<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]900<p>The function type can be thought of as a function signature. It
901consists of a return type and a list of formal parameter types.
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]902Function types are usually used to build virtual function tables
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]903(which are structures of pointers to functions), for indirect function
904calls, and when defining a function.</p>
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]905<p>
906The return type of a function type cannot be an aggregate type.
907</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]908<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]909<pre> &lt;returntype&gt; (&lt;parameter list&gt;)<br></pre>
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]910<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]911specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]912which indicates that the function takes a variable number of arguments.
913Variable argument functions can access their arguments with the <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]914 href="#int_varargs">variable argument handling intrinsic</a> functions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]915<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]916<table class="layout">
917 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]918 <td class="left"><tt>i32 (i32)</tt></td>
919 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]920 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]921 </tr><tr class="layout">
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]922 <td class="left"><tt>float&nbsp;(i16&nbsp;@sext,&nbsp;i32&nbsp;*)&nbsp;*
923 </tt></td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]924 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
925 an <tt>i16</tt> that should be sign extended and a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]926 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]927 <tt>float</tt>.
928 </td>
929 </tr><tr class="layout">
930 <td class="left"><tt>i32 (i8*, ...)</tt></td>
931 <td class="left">A vararg function that takes at least one
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]932 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]933 which returns an integer. This is the signature for <tt>printf</tt> in
934 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]935 </td>
936 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]937</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]938
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]939</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]940<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]941<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]942<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]943<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]944<p>The structure type is used to represent a collection of data members
945together in memory. The packing of the field types is defined to match
946the ABI of the underlying processor. The elements of a structure may
947be any type that has a size.</p>
948<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
949and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
950field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
951instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]952<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]953<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]954<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]955<table class="layout">
956 <tr class="layout">
957 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]958 <tt>{ i32, i32, i32 }</tt><br/>
959 <tt>{ float, i32 (i32) * }</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]960 </td>
961 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]962 a triple of three <tt>i32</tt> values<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]963 A pair, where the first element is a <tt>float</tt> and the second element
964 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]965 that takes an <tt>i32</tt>, returning an <tt>i32</tt>.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]966 </td>
967 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]968</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]969</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]970
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]971<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]972<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
973</div>
974<div class="doc_text">
975<h5>Overview:</h5>
976<p>The packed structure type is used to represent a collection of data members
977together in memory. There is no padding between fields. Further, the alignment
978of a packed structure is 1 byte. The elements of a packed structure may
979be any type that has a size.</p>
980<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
981and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
982field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
983instruction.</p>
984<h5>Syntax:</h5>
985<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
986<h5>Examples:</h5>
987<table class="layout">
988 <tr class="layout">
989 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]990 <tt> &lt; { i32, i32, i32 } &gt; </tt><br/>
991 <tt> &lt; { float, i32 (i32) * } &gt; </tt><br/>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]992 </td>
993 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]994 a triple of three <tt>i32</tt> values<br/>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]995 A pair, where the first element is a <tt>float</tt> and the second element
996 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]997 that takes an <tt>i32</tt>, returning an <tt>i32</tt>.<br/>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]998 </td>
999 </tr>
1000</table>
1001</div>
1002
1003<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1004<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1005<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1006<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1007<p>As in many languages, the pointer type represents a pointer or
1008reference to another object, which must live in memory.</p>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1009<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1010<pre> &lt;type&gt; *<br></pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1011<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1012<table class="layout">
1013 <tr class="layout">
1014 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1015 <tt>[4x i32]*</tt><br/>
1016 <tt>i32 (i32 *) *</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1017 </td>
1018 <td class="left">
1019 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]1020 four <tt>i32</tt> values<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1021 A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1022 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
1023 <tt>i32</tt>.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1024 </td>
1025 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1026</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1027</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1028
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1029<!-- _______________________________________________________________________ -->
1030<div class="doc_subsubsection"> <a name="t_packed">Packed Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1031<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1032
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1033<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1034
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1035<p>A packed type is a simple derived type that represents a vector
1036of elements. Packed types are used when multiple primitive data
1037are operated in parallel using a single instruction (SIMD).
1038A packed type requires a size (number of
Chris Lattnerb8d172f2005-11-10 01:44:22 +0000[diff] [blame]1039elements) and an underlying primitive data type. Vectors must have a power
1040of two length (1, 2, 4, 8, 16 ...). Packed types are
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1041considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1042
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1043<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1044
1045<pre>
1046 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1047</pre>
1048
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1049<p>The number of elements is a constant integer value; elementtype may
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1050be any integral or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1051
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1052<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1053
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1054<table class="layout">
1055 <tr class="layout">
1056 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1057 <tt>&lt;4 x i32&gt;</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1058 <tt>&lt;8 x float&gt;</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1059 <tt>&lt;2 x i64&gt;</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1060 </td>
1061 <td class="left">
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1062 Packed vector of 4 32-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1063 Packed vector of 8 floating-point values.<br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1064 Packed vector of 2 64-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1065 </td>
1066 </tr>
1067</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1068</div>
1069
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1070<!-- _______________________________________________________________________ -->
1071<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1072<div class="doc_text">
1073
1074<h5>Overview:</h5>
1075
1076<p>Opaque types are used to represent unknown types in the system. This
1077corresponds (for example) to the C notion of a foward declared structure type.
1078In LLVM, opaque types can eventually be resolved to any type (not just a
1079structure type).</p>
1080
1081<h5>Syntax:</h5>
1082
1083<pre>
1084 opaque
1085</pre>
1086
1087<h5>Examples:</h5>
1088
1089<table class="layout">
1090 <tr class="layout">
1091 <td class="left">
1092 <tt>opaque</tt>
1093 </td>
1094 <td class="left">
1095 An opaque type.<br/>
1096 </td>
1097 </tr>
1098</table>
1099</div>
1100
1101
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1102<!-- *********************************************************************** -->
1103<div class="doc_section"> <a name="constants">Constants</a> </div>
1104<!-- *********************************************************************** -->
1105
1106<div class="doc_text">
1107
1108<p>LLVM has several different basic types of constants. This section describes
1109them all and their syntax.</p>
1110
1111</div>
1112
1113<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1114<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1115
1116<div class="doc_text">
1117
1118<dl>
1119 <dt><b>Boolean constants</b></dt>
1120
1121 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
1122 constants of the <tt><a href="#t_primitive">bool</a></tt> type.
1123 </dd>
1124
1125 <dt><b>Integer constants</b></dt>
1126
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1127 <dd>Standard integers (such as '4') are constants of the <a
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1128 href="#t_integer">integer</a> type. Negative numbers may be used with
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1129 integer types.
1130 </dd>
1131
1132 <dt><b>Floating point constants</b></dt>
1133
1134 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1135 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1136 notation (see below). Floating point constants must have a <a
1137 href="#t_floating">floating point</a> type. </dd>
1138
1139 <dt><b>Null pointer constants</b></dt>
1140
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1141 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1142 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1143
1144</dl>
1145
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1146<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1147of floating point constants. For example, the form '<tt>double
11480x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
11494.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1150(and the only time that they are generated by the disassembler) is when a
1151floating point constant must be emitted but it cannot be represented as a
1152decimal floating point number. For example, NaN's, infinities, and other
1153special values are represented in their IEEE hexadecimal format so that
1154assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1155
1156</div>
1157
1158<!-- ======================================================================= -->
1159<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1160</div>
1161
1162<div class="doc_text">
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1163<p>Aggregate constants arise from aggregation of simple constants
1164and smaller aggregate constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1165
1166<dl>
1167 <dt><b>Structure constants</b></dt>
1168
1169 <dd>Structure constants are represented with notation similar to structure
1170 type definitions (a comma separated list of elements, surrounded by braces
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1171 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* %G }</tt>",
1172 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]1173 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1174 types of elements must match those specified by the type.
1175 </dd>
1176
1177 <dt><b>Array constants</b></dt>
1178
1179 <dd>Array constants are represented with notation similar to array type
1180 definitions (a comma separated list of elements, surrounded by square brackets
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1181 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1182 constants must have <a href="#t_array">array type</a>, and the number and
1183 types of elements must match those specified by the type.
1184 </dd>
1185
1186 <dt><b>Packed constants</b></dt>
1187
1188 <dd>Packed constants are represented with notation similar to packed type
1189 definitions (a comma separated list of elements, surrounded by
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1190 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32 42,
1191 i32 11, i32 74, i32 100 &gt;</tt>". Packed constants must have <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1192 href="#t_packed">packed type</a>, and the number and types of elements must
1193 match those specified by the type.
1194 </dd>
1195
1196 <dt><b>Zero initialization</b></dt>
1197
1198 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1199 value to zero of <em>any</em> type, including scalar and aggregate types.
1200 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]1201 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1202 initializers.
1203 </dd>
1204</dl>
1205
1206</div>
1207
1208<!-- ======================================================================= -->
1209<div class="doc_subsection">
1210 <a name="globalconstants">Global Variable and Function Addresses</a>
1211</div>
1212
1213<div class="doc_text">
1214
1215<p>The addresses of <a href="#globalvars">global variables</a> and <a
1216href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1217constants. These constants are explicitly referenced when the <a
1218href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1219href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1220file:</p>
1221
1222<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1223 %X = global i32 17
1224 %Y = global i32 42
1225 %Z = global [2 x i32*] [ i32* %X, i32* %Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1226</pre>
1227
1228</div>
1229
1230<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1231<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1232<div class="doc_text">
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1233 <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]1234 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1235 a constant is permitted.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1236
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1237 <p>Undefined values indicate to the compiler that the program is well defined
1238 no matter what value is used, giving the compiler more freedom to optimize.
1239 </p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1240</div>
1241
1242<!-- ======================================================================= -->
1243<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1244</div>
1245
1246<div class="doc_text">
1247
1248<p>Constant expressions are used to allow expressions involving other constants
1249to be used as constants. Constant expressions may be of any <a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1250href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1251that does not have side effects (e.g. load and call are not supported). The
1252following is the syntax for constant expressions:</p>
1253
1254<dl>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1255 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1256 <dd>Truncate a constant to another type. The bit size of CST must be larger
1257 than the bit size of TYPE. Both types must be integral.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1258
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1259 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1260 <dd>Zero extend a constant to another type. The bit size of CST must be
1261 smaller or equal to the bit size of TYPE. Both types must be integral.</dd>
1262
1263 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1264 <dd>Sign extend a constant to another type. The bit size of CST must be
1265 smaller or equal to the bit size of TYPE. Both types must be integral.</dd>
1266
1267 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1268 <dd>Truncate a floating point constant to another floating point type. The
1269 size of CST must be larger than the size of TYPE. Both types must be
1270 floating point.</dd>
1271
1272 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1273 <dd>Floating point extend a constant to another type. The size of CST must be
1274 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1275
1276 <dt><b><tt>fp2uint ( CST to TYPE )</tt></b></dt>
1277 <dd>Convert a floating point constant to the corresponding unsigned integer
1278 constant. TYPE must be an integer type. CST must be floating point. If the
1279 value won't fit in the integer type, the results are undefined.</dd>
1280
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1281 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1282 <dd>Convert a floating point constant to the corresponding signed integer
1283 constant. TYPE must be an integer type. CST must be floating point. If the
1284 value won't fit in the integer type, the results are undefined.</dd>
1285
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1286 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1287 <dd>Convert an unsigned integer constant to the corresponding floating point
1288 constant. TYPE must be floating point. CST must be of integer type. If the
1289 value won't fit in the floating point type, the results are undefined.</dd>
1290
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1291 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1292 <dd>Convert a signed integer constant to the corresponding floating point
1293 constant. TYPE must be floating point. CST must be of integer type. If the
1294 value won't fit in the floating point type, the results are undefined.</dd>
1295
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]1296 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1297 <dd>Convert a pointer typed constant to the corresponding integer constant
1298 TYPE must be an integer type. CST must be of pointer type. The CST value is
1299 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1300
1301 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1302 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1303 pointer type. CST must be of integer type. The CST value is zero extended,
1304 truncated, or unchanged to make it fit in a pointer size. This one is
1305 <i>really</i> dangerous!</dd>
1306
1307 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1308 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1309 identical (same number of bits). The conversion is done as if the CST value
1310 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]1311 with this operator, just the type. This can be used for conversion of
1312 packed types to any other type, as long as they have the same bit width. For
1313 pointers it is only valid to cast to another pointer type.
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1314 </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1315
1316 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1317
1318 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1319 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1320 instruction, the index list may have zero or more indexes, which are required
1321 to make sense for the type of "CSTPTR".</dd>
1322
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1323 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1324
1325 <dd>Perform the <a href="#i_select">select operation</a> on
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1326 constants.</dd>
1327
1328 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1329 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1330
1331 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1332 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1333
1334 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1335
1336 <dd>Perform the <a href="#i_extractelement">extractelement
1337 operation</a> on constants.
1338
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1339 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1340
1341 <dd>Perform the <a href="#i_insertelement">insertelement
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1342 operation</a> on constants.</dd>
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1343
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1344
1345 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1346
1347 <dd>Perform the <a href="#i_shufflevector">shufflevector
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1348 operation</a> on constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1349
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1350 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1351
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1352 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1353 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1354 binary</a> operations. The constraints on operands are the same as those for
1355 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1356 values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1357</dl>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1358</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]1359
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1360<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1361<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1362<!-- *********************************************************************** -->
1363
1364<!-- ======================================================================= -->
1365<div class="doc_subsection">
1366<a name="inlineasm">Inline Assembler Expressions</a>
1367</div>
1368
1369<div class="doc_text">
1370
1371<p>
1372LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1373Module-Level Inline Assembly</a>) through the use of a special value. This
1374value represents the inline assembler as a string (containing the instructions
1375to emit), a list of operand constraints (stored as a string), and a flag that
1376indicates whether or not the inline asm expression has side effects. An example
1377inline assembler expression is:
1378</p>
1379
1380<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1381 i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1382</pre>
1383
1384<p>
1385Inline assembler expressions may <b>only</b> be used as the callee operand of
1386a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1387</p>
1388
1389<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1390 %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]1391</pre>
1392
1393<p>
1394Inline asms with side effects not visible in the constraint list must be marked
1395as having side effects. This is done through the use of the
1396'<tt>sideeffect</tt>' keyword, like so:
1397</p>
1398
1399<pre>
1400 call void asm sideeffect "eieio", ""()
1401</pre>
1402
1403<p>TODO: The format of the asm and constraints string still need to be
1404documented here. Constraints on what can be done (e.g. duplication, moving, etc
1405need to be documented).
1406</p>
1407
1408</div>
1409
1410<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1411<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1412<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1413
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1414<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1415
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1416<p>The LLVM instruction set consists of several different
1417classifications of instructions: <a href="#terminators">terminator
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1418instructions</a>, <a href="#binaryops">binary instructions</a>,
1419<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1420 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1421instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1422
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1423</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1424
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1425<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1426<div class="doc_subsection"> <a name="terminators">Terminator
1427Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1428
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1429<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1430
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1431<p>As mentioned <a href="#functionstructure">previously</a>, every
1432basic block in a program ends with a "Terminator" instruction, which
1433indicates which block should be executed after the current block is
1434finished. These terminator instructions typically yield a '<tt>void</tt>'
1435value: they produce control flow, not values (the one exception being
1436the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1437<p>There are six different terminator instructions: the '<a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1438 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1439instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1440the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1441 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1442 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1443
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1444</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1445
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1446<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1447<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1448Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1449<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1450<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1451<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]1452 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1453</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1454<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1455<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1456value) from a function back to the caller.</p>
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]1457<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1458returns a value and then causes control flow, and one that just causes
1459control flow to occur.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1460<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1461<p>The '<tt>ret</tt>' instruction may return any '<a
1462 href="#t_firstclass">first class</a>' type. Notice that a function is
1463not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
1464instruction inside of the function that returns a value that does not
1465match the return type of the function.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1466<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1467<p>When the '<tt>ret</tt>' instruction is executed, control flow
1468returns back to the calling function's context. If the caller is a "<a
John Criswellfa081872004-06-25 15:16:57 +0000[diff] [blame]1469 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1470the instruction after the call. If the caller was an "<a
1471 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1472at the beginning of the "normal" destination block. If the instruction
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1473returns a value, that value shall set the call or invoke instruction's
1474return value.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1475<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1476<pre> ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1477 ret void <i>; Return from a void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1478</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1479</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1480<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1481<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1482<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1483<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1484<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]1485</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1486<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1487<p>The '<tt>br</tt>' instruction is used to cause control flow to
1488transfer to a different basic block in the current function. There are
1489two forms of this instruction, corresponding to a conditional branch
1490and an unconditional branch.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1491<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1492<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
1493single '<tt>bool</tt>' value and two '<tt>label</tt>' values. The
1494unconditional form of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>'
1495value as a target.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1496<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1497<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>bool</tt>'
1498argument is evaluated. If the value is <tt>true</tt>, control flows
1499to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1500control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1501<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1502<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
1503 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]1504</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1505<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1506<div class="doc_subsubsection">
1507 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1508</div>
1509
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1510<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1511<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1512
1513<pre>
1514 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1515</pre>
1516
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1517<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1518
1519<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1520several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1521instruction, allowing a branch to occur to one of many possible
1522destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1523
1524
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1525<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1526
1527<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1528comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1529an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1530table is not allowed to contain duplicate constant entries.</p>
1531
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1532<h5>Semantics:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1533
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1534<p>The <tt>switch</tt> instruction specifies a table of values and
1535destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1536table is searched for the given value. If the value is found, control flow is
1537transfered to the corresponding destination; otherwise, control flow is
1538transfered to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1539
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1540<h5>Implementation:</h5>
1541
1542<p>Depending on properties of the target machine and the particular
1543<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1544ways. For example, it could be generated as a series of chained conditional
1545branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1546
1547<h5>Example:</h5>
1548
1549<pre>
1550 <i>; Emulate a conditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1551 %Val = <a href="#i_zext">zext</a> bool %value to i32
1552 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1553
1554 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1555 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1556
1557 <i>; Implement a jump table:</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1558 switch i32 %val, label %otherwise [ i32 0, label %onzero
1559 i32 1, label %onone
1560 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1561</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1562</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1563
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1564<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1565<div class="doc_subsubsection">
1566 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1567</div>
1568
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1569<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1570
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1571<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1572
1573<pre>
1574 &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]1575 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1576</pre>
1577
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1578<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1579
1580<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1581function, with the possibility of control flow transfer to either the
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1582'<tt>normal</tt>' label or the
1583'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1584"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1585"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1586href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
1587continued at the dynamically nearest "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1588
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1589<h5>Arguments:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1590
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1591<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1592
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1593<ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1594 <li>
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1595 The optional "cconv" marker indicates which <a href="callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1596 convention</a> the call should use. If none is specified, the call defaults
1597 to using C calling conventions.
1598 </li>
1599 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1600 function value being invoked. In most cases, this is a direct function
1601 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1602 an arbitrary pointer to function value.
1603 </li>
1604
1605 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1606 function to be invoked. </li>
1607
1608 <li>'<tt>function args</tt>': argument list whose types match the function
1609 signature argument types. If the function signature indicates the function
1610 accepts a variable number of arguments, the extra arguments can be
1611 specified. </li>
1612
1613 <li>'<tt>normal label</tt>': the label reached when the called function
1614 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1615
1616 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1617 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1618
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1619</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1620
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1621<h5>Semantics:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1622
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1623<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1624href="#i_call">call</a></tt>' instruction in most regards. The primary
1625difference is that it establishes an association with a label, which is used by
1626the runtime library to unwind the stack.</p>
1627
1628<p>This instruction is used in languages with destructors to ensure that proper
1629cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1630exception. Additionally, this is important for implementation of
1631'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1632
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1633<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1634<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1635 %retval = invoke i32 %Test(i32 15) to label %Continue
1636 unwind label %TestCleanup <i>; {i32}:retval set</i>
1637 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Test(i32 15) to label %Continue
1638 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1639</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1640</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1641
1642
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1643<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1644
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1645<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1646Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1647
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1648<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1649
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1650<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1651<pre>
1652 unwind
1653</pre>
1654
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1655<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1656
1657<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
1658at the first callee in the dynamic call stack which used an <a
1659href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
1660primarily used to implement exception handling.</p>
1661
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1662<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1663
1664<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
1665immediately halt. The dynamic call stack is then searched for the first <a
1666href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
1667execution continues at the "exceptional" destination block specified by the
1668<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
1669dynamic call chain, undefined behavior results.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1670</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1671
1672<!-- _______________________________________________________________________ -->
1673
1674<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
1675Instruction</a> </div>
1676
1677<div class="doc_text">
1678
1679<h5>Syntax:</h5>
1680<pre>
1681 unreachable
1682</pre>
1683
1684<h5>Overview:</h5>
1685
1686<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
1687instruction is used to inform the optimizer that a particular portion of the
1688code is not reachable. This can be used to indicate that the code after a
1689no-return function cannot be reached, and other facts.</p>
1690
1691<h5>Semantics:</h5>
1692
1693<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
1694</div>
1695
1696
1697
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1698<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1699<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1700<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1701<p>Binary operators are used to do most of the computation in a
1702program. They require two operands, execute an operation on them, and
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1703produce a single value. The operands might represent
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1704multiple data, as is the case with the <a href="#t_packed">packed</a> data type.
1705The result value of a binary operator is not
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1706necessarily the same type as its operands.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1707<p>There are several different binary operators:</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1708</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1709<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1710<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
1711Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1712<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1713<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1714<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]1715</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1716<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1717<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1718<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1719<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1720 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
1721 This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1722Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1723<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1724<p>The value produced is the integer or floating point sum of the two
1725operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1726<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1727<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]1728</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1729</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1730<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1731<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
1732Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1733<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1734<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1735<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]1736</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1737<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1738<p>The '<tt>sub</tt>' instruction returns the difference of its two
1739operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1740<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
1741instruction present in most other intermediate representations.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1742<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1743<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1744 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1745values.
1746This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1747Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1748<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1749<p>The value produced is the integer or floating point difference of
1750the two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1751<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1752<pre> &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
1753 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1754</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1755</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1756<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1757<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
1758Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1759<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1760<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1761<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]1762</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1763<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1764<p>The '<tt>mul</tt>' instruction returns the product of its two
1765operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1766<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1767<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1768 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1769values.
1770This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1771Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1772<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1773<p>The value produced is the integer or floating point product of the
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1774two operands.</p>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1775<p>Because the operands are the same width, the result of an integer
1776multiplication is the same whether the operands should be deemed unsigned or
1777signed.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1778<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1779<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]1780</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1781</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1782<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1783<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
1784</a></div>
1785<div class="doc_text">
1786<h5>Syntax:</h5>
1787<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1788</pre>
1789<h5>Overview:</h5>
1790<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
1791operands.</p>
1792<h5>Arguments:</h5>
1793<p>The two arguments to the '<tt>udiv</tt>' instruction must be
1794<a href="#t_integer">integer</a> values. Both arguments must have identical
1795types. This instruction can also take <a href="#t_packed">packed</a> versions
1796of the values in which case the elements must be integers.</p>
1797<h5>Semantics:</h5>
1798<p>The value produced is the unsigned integer quotient of the two operands. This
1799instruction always performs an unsigned division operation, regardless of
1800whether the arguments are unsigned or not.</p>
1801<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1802<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]1803</pre>
1804</div>
1805<!-- _______________________________________________________________________ -->
1806<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
1807</a> </div>
1808<div class="doc_text">
1809<h5>Syntax:</h5>
1810<pre> &lt;result&gt; = sdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1811</pre>
1812<h5>Overview:</h5>
1813<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
1814operands.</p>
1815<h5>Arguments:</h5>
1816<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
1817<a href="#t_integer">integer</a> values. Both arguments must have identical
1818types. This instruction can also take <a href="#t_packed">packed</a> versions
1819of the values in which case the elements must be integers.</p>
1820<h5>Semantics:</h5>
1821<p>The value produced is the signed integer quotient of the two operands. This
1822instruction always performs a signed division operation, regardless of whether
1823the arguments are signed or not.</p>
1824<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1825<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]1826</pre>
1827</div>
1828<!-- _______________________________________________________________________ -->
1829<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1830Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1831<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1832<h5>Syntax:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1833<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]1834</pre>
1835<h5>Overview:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1836<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1837operands.</p>
1838<h5>Arguments:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1839<p>The two arguments to the '<tt>div</tt>' instruction must be
1840<a href="#t_floating">floating point</a> values. Both arguments must have
1841identical types. This instruction can also take <a href="#t_packed">packed</a>
1842versions of the values in which case the elements must be floating point.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1843<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1844<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1845<h5>Example:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1846<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]1847</pre>
1848</div>
1849<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1850<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
1851</div>
1852<div class="doc_text">
1853<h5>Syntax:</h5>
1854<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1855</pre>
1856<h5>Overview:</h5>
1857<p>The '<tt>urem</tt>' instruction returns the remainder from the
1858unsigned division of its two arguments.</p>
1859<h5>Arguments:</h5>
1860<p>The two arguments to the '<tt>urem</tt>' instruction must be
1861<a href="#t_integer">integer</a> values. Both arguments must have identical
1862types.</p>
1863<h5>Semantics:</h5>
1864<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
1865This instruction always performs an unsigned division to get the remainder,
1866regardless of whether the arguments are unsigned or not.</p>
1867<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1868<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]1869</pre>
1870
1871</div>
1872<!-- _______________________________________________________________________ -->
1873<div class="doc_subsubsection"> <a name="i_srem">'<tt>srem</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1874Instruction</a> </div>
1875<div class="doc_text">
1876<h5>Syntax:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1877<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]1878</pre>
1879<h5>Overview:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1880<p>The '<tt>srem</tt>' instruction returns the remainder from the
1881signed division of its two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1882<h5>Arguments:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1883<p>The two arguments to the '<tt>srem</tt>' instruction must be
1884<a href="#t_integer">integer</a> values. Both arguments must have identical
1885types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1886<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1887<p>This instruction returns the <i>remainder</i> of a division (where the result
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1888has the same sign as the divisor), not the <i>modulus</i> (where the
1889result has the same sign as the dividend) of a value. For more
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1890information about the difference, see <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1891 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
1892Math Forum</a>.</p>
1893<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1894<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]1895</pre>
1896
1897</div>
1898<!-- _______________________________________________________________________ -->
1899<div class="doc_subsubsection"> <a name="i_frem">'<tt>frem</tt>'
1900Instruction</a> </div>
1901<div class="doc_text">
1902<h5>Syntax:</h5>
1903<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1904</pre>
1905<h5>Overview:</h5>
1906<p>The '<tt>frem</tt>' instruction returns the remainder from the
1907division of its two operands.</p>
1908<h5>Arguments:</h5>
1909<p>The two arguments to the '<tt>frem</tt>' instruction must be
1910<a href="#t_floating">floating point</a> values. Both arguments must have
1911identical types.</p>
1912<h5>Semantics:</h5>
1913<p>This instruction returns the <i>remainder</i> of a division.</p>
1914<h5>Example:</h5>
1915<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]1916</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1917</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]1918
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1919<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1920<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
1921Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1922<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1923<p>Bitwise binary operators are used to do various forms of
1924bit-twiddling in a program. They are generally very efficient
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1925instructions and can commonly be strength reduced from other
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1926instructions. They require two operands, execute an operation on them,
1927and produce a single value. The resulting value of the bitwise binary
1928operators is always the same type as its first operand.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1929</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1930<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1931<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
1932Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1933<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1934<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1935<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]1936</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1937<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1938<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
1939its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1940<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1941<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1942 href="#t_integral">integral</a> values. Both arguments must have
1943identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1944<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1945<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1946<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1947<div style="align: center">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1948<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1949 <tbody>
1950 <tr>
1951 <td>In0</td>
1952 <td>In1</td>
1953 <td>Out</td>
1954 </tr>
1955 <tr>
1956 <td>0</td>
1957 <td>0</td>
1958 <td>0</td>
1959 </tr>
1960 <tr>
1961 <td>0</td>
1962 <td>1</td>
1963 <td>0</td>
1964 </tr>
1965 <tr>
1966 <td>1</td>
1967 <td>0</td>
1968 <td>0</td>
1969 </tr>
1970 <tr>
1971 <td>1</td>
1972 <td>1</td>
1973 <td>1</td>
1974 </tr>
1975 </tbody>
1976</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1977</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1978<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1979<pre> &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
1980 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
1981 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1982</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1983</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1984<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1985<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1986<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1987<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1988<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]1989</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1990<h5>Overview:</h5>
1991<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
1992or of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1993<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1994<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1995 href="#t_integral">integral</a> values. Both arguments must have
1996identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1997<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1998<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1999<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2000<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2001<table border="1" cellspacing="0" cellpadding="4">
2002 <tbody>
2003 <tr>
2004 <td>In0</td>
2005 <td>In1</td>
2006 <td>Out</td>
2007 </tr>
2008 <tr>
2009 <td>0</td>
2010 <td>0</td>
2011 <td>0</td>
2012 </tr>
2013 <tr>
2014 <td>0</td>
2015 <td>1</td>
2016 <td>1</td>
2017 </tr>
2018 <tr>
2019 <td>1</td>
2020 <td>0</td>
2021 <td>1</td>
2022 </tr>
2023 <tr>
2024 <td>1</td>
2025 <td>1</td>
2026 <td>1</td>
2027 </tr>
2028 </tbody>
2029</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2030</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2031<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2032<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2033 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2034 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2035</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2036</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2037<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2038<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2039Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2040<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2041<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2042<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]2043</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2044<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2045<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2046or of its two operands. The <tt>xor</tt> is used to implement the
2047"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2048<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2049<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2050 href="#t_integral">integral</a> values. Both arguments must have
2051identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2052<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2053<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2054<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2055<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2056<table border="1" cellspacing="0" cellpadding="4">
2057 <tbody>
2058 <tr>
2059 <td>In0</td>
2060 <td>In1</td>
2061 <td>Out</td>
2062 </tr>
2063 <tr>
2064 <td>0</td>
2065 <td>0</td>
2066 <td>0</td>
2067 </tr>
2068 <tr>
2069 <td>0</td>
2070 <td>1</td>
2071 <td>1</td>
2072 </tr>
2073 <tr>
2074 <td>1</td>
2075 <td>0</td>
2076 <td>1</td>
2077 </tr>
2078 <tr>
2079 <td>1</td>
2080 <td>1</td>
2081 <td>0</td>
2082 </tr>
2083 </tbody>
2084</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2085</div>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2086<p> </p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2087<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2088<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2089 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2090 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2091 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2092</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2093</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2094<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2095<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2096Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2097<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2098<h5>Syntax:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2099<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]2100</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2101<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2102<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2103the left a specified number of bits.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2104<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2105<p>The first argument to the '<tt>shl</tt>' instruction must be an <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2106 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]2107type.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2108<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2109<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]2110<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2111<pre> &lt;result&gt; = shl i32 4, i8 %var <i>; yields {i32}:result = 4 &lt;&lt; %var</i>
2112 &lt;result&gt; = shl i32 4, i8 2 <i>; yields {i32}:result = 16</i>
2113 &lt;result&gt; = shl i32 1, i8 10 <i>; yields {i32}:result = 1024</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2114</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2115</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2116<!-- _______________________________________________________________________ -->
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2117<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2118Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2119<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2120<h5>Syntax:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2121<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]2122</pre>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2123
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2124<h5>Overview:</h5>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2125<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
2126operand shifted to the right a specified number of bits.</p>
2127
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2128<h5>Arguments:</h5>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2129<p>The first argument to the '<tt>lshr</tt>' instruction must be an <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2130 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]2131
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2132<h5>Semantics:</h5>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]2133<p>This instruction always performs a logical shift right operation. The
2134<tt>var2</tt> most significant bits will be filled with zero bits after the
2135shift.</p>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2136
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2137<h5>Example:</h5>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2138<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2139 &lt;result&gt; = lshr i32 4, i8 1 <i>; yields {i32}:result = 2</i>
2140 &lt;result&gt; = lshr i32 4, i8 2 <i>; yields {i32}:result = 1</i>
2141 &lt;result&gt; = lshr i8 4, i8 3 <i>; yields {i8 }:result = 0</i>
2142 &lt;result&gt; = lshr i8 -2, i8 1 <i>; yields {i8 }:result = 0x7FFFFFFF </i>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2143</pre>
2144</div>
2145
2146<!-- ======================================================================= -->
2147<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2148Instruction</a> </div>
2149<div class="doc_text">
2150
2151<h5>Syntax:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2152<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]2153</pre>
2154
2155<h5>Overview:</h5>
2156<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
2157operand shifted to the right a specified number of bits.</p>
2158
2159<h5>Arguments:</h5>
2160<p>The first argument to the '<tt>ashr</tt>' instruction must be an
2161<a href="#t_integer">integer</a> type. The second argument must be an
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2162'<tt>i8</tt>' type.</p>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2163
2164<h5>Semantics:</h5>
2165<p>This instruction always performs an arithmetic shift right operation,
2166regardless of whether the arguments are signed or not. The <tt>var2</tt> most
2167significant bits will be filled with the sign bit of <tt>var1</tt>.</p>
2168
2169<h5>Example:</h5>
2170<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2171 &lt;result&gt; = ashr i32 4, i8 1 <i>; yields {i32}:result = 2</i>
2172 &lt;result&gt; = ashr i32 4, i8 2 <i>; yields {i32}:result = 1</i>
2173 &lt;result&gt; = ashr i8 4, i8 3 <i>; yields {i8}:result = 0</i>
2174 &lt;result&gt; = ashr i8 -2, i8 1 <i>; yields {i8 }:result = -1</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2175</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2176</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2177
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2178<!-- ======================================================================= -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2179<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2180 <a name="vectorops">Vector Operations</a>
2181</div>
2182
2183<div class="doc_text">
2184
2185<p>LLVM supports several instructions to represent vector operations in a
2186target-independent manner. This instructions cover the element-access and
2187vector-specific operations needed to process vectors effectively. While LLVM
2188does directly support these vector operations, many sophisticated algorithms
2189will want to use target-specific intrinsics to take full advantage of a specific
2190target.</p>
2191
2192</div>
2193
2194<!-- _______________________________________________________________________ -->
2195<div class="doc_subsubsection">
2196 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2197</div>
2198
2199<div class="doc_text">
2200
2201<h5>Syntax:</h5>
2202
2203<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2204 &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]2205</pre>
2206
2207<h5>Overview:</h5>
2208
2209<p>
2210The '<tt>extractelement</tt>' instruction extracts a single scalar
2211element from a packed vector at a specified index.
2212</p>
2213
2214
2215<h5>Arguments:</h5>
2216
2217<p>
2218The first operand of an '<tt>extractelement</tt>' instruction is a
2219value of <a href="#t_packed">packed</a> type. The second operand is
2220an index indicating the position from which to extract the element.
2221The index may be a variable.</p>
2222
2223<h5>Semantics:</h5>
2224
2225<p>
2226The result is a scalar of the same type as the element type of
2227<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2228<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2229results are undefined.
2230</p>
2231
2232<h5>Example:</h5>
2233
2234<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2235 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2236</pre>
2237</div>
2238
2239
2240<!-- _______________________________________________________________________ -->
2241<div class="doc_subsubsection">
2242 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2243</div>
2244
2245<div class="doc_text">
2246
2247<h5>Syntax:</h5>
2248
2249<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2250 &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]2251</pre>
2252
2253<h5>Overview:</h5>
2254
2255<p>
2256The '<tt>insertelement</tt>' instruction inserts a scalar
2257element into a packed vector at a specified index.
2258</p>
2259
2260
2261<h5>Arguments:</h5>
2262
2263<p>
2264The first operand of an '<tt>insertelement</tt>' instruction is a
2265value of <a href="#t_packed">packed</a> type. The second operand is a
2266scalar value whose type must equal the element type of the first
2267operand. The third operand is an index indicating the position at
2268which to insert the value. The index may be a variable.</p>
2269
2270<h5>Semantics:</h5>
2271
2272<p>
2273The result is a packed vector of the same type as <tt>val</tt>. Its
2274element values are those of <tt>val</tt> except at position
2275<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2276exceeds the length of <tt>val</tt>, the results are undefined.
2277</p>
2278
2279<h5>Example:</h5>
2280
2281<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2282 %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]2283</pre>
2284</div>
2285
2286<!-- _______________________________________________________________________ -->
2287<div class="doc_subsubsection">
2288 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2289</div>
2290
2291<div class="doc_text">
2292
2293<h5>Syntax:</h5>
2294
2295<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2296 &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]2297</pre>
2298
2299<h5>Overview:</h5>
2300
2301<p>
2302The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2303from two input vectors, returning a vector of the same type.
2304</p>
2305
2306<h5>Arguments:</h5>
2307
2308<p>
2309The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2310with types that match each other and types that match the result of the
2311instruction. The third argument is a shuffle mask, which has the same number
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2312of elements as the other vector type, but whose element type is always 'i32'.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2313</p>
2314
2315<p>
2316The shuffle mask operand is required to be a constant vector with either
2317constant integer or undef values.
2318</p>
2319
2320<h5>Semantics:</h5>
2321
2322<p>
2323The elements of the two input vectors are numbered from left to right across
2324both of the vectors. The shuffle mask operand specifies, for each element of
2325the result vector, which element of the two input registers the result element
2326gets. The element selector may be undef (meaning "don't care") and the second
2327operand may be undef if performing a shuffle from only one vector.
2328</p>
2329
2330<h5>Example:</h5>
2331
2332<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2333 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
2334 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
2335 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2336 &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]2337</pre>
2338</div>
2339
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]2340
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2341<!-- ======================================================================= -->
2342<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2343 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2344</div>
2345
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2346<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2347
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2348<p>A key design point of an SSA-based representation is how it
2349represents memory. In LLVM, no memory locations are in SSA form, which
2350makes things very simple. This section describes how to read, write,
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2351allocate, and free memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2352
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2353</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2354
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2355<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2356<div class="doc_subsubsection">
2357 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2358</div>
2359
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2360<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2361
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2362<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2363
2364<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2365 &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]2366</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2367
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2368<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2369
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2370<p>The '<tt>malloc</tt>' instruction allocates memory from the system
2371heap and returns a pointer to it.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2372
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2373<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2374
2375<p>The '<tt>malloc</tt>' instruction allocates
2376<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswell6e4ca612004-02-24 16:13:56 +0000[diff] [blame]2377bytes of memory from the operating system and returns a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2378appropriate type to the program. If "NumElements" is specified, it is the
2379number of elements allocated. If an alignment is specified, the value result
2380of the allocation is guaranteed to be aligned to at least that boundary. If
2381not specified, or if zero, the target can choose to align the allocation on any
2382convenient boundary.</p>
2383
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2384<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2385
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2386<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2387
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2388<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
2389a pointer is returned.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2390
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2391<h5>Example:</h5>
2392
2393<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2394 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2395
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2396 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
2397 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
2398 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
2399 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
2400 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2401</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2402</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2403
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2404<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2405<div class="doc_subsubsection">
2406 <a name="i_free">'<tt>free</tt>' Instruction</a>
2407</div>
2408
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2409<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2410
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2411<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2412
2413<pre>
2414 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2415</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2416
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2417<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2418
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2419<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2420memory heap to be reallocated in the future.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2421
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2422<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2423
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2424<p>'<tt>value</tt>' shall be a pointer value that points to a value
2425that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
2426instruction.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2427
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2428<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2429
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2430<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2431after this instruction executes.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2432
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2433<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2434
2435<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2436 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
2437 free [4 x i8]* %array
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2438</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2439</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2440
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2441<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2442<div class="doc_subsubsection">
2443 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
2444</div>
2445
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2446<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2447
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2448<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2449
2450<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2451 &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]2452</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2453
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2454<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2455
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2456<p>The '<tt>alloca</tt>' instruction allocates memory on the current
2457stack frame of the procedure that is live until the current function
2458returns to its caller.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2459
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2460<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2461
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2462<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2463bytes of memory on the runtime stack, returning a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2464appropriate type to the program. If "NumElements" is specified, it is the
2465number of elements allocated. If an alignment is specified, the value result
2466of the allocation is guaranteed to be aligned to at least that boundary. If
2467not specified, or if zero, the target can choose to align the allocation on any
2468convenient boundary.</p>
2469
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2470<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2471
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2472<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2473
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2474<p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2475memory is automatically released when the function returns. The '<tt>alloca</tt>'
2476instruction is commonly used to represent automatic variables that must
2477have an address available. When the function returns (either with the <tt><a
John Criswelldae2e932005-05-12 16:55:34 +0000[diff] [blame]2478 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]2479instructions), the memory is reclaimed.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2480
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2481<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2482
2483<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2484 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
2485 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
2486 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
2487 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2488</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2489</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2490
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2491<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2492<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
2493Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2494<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2495<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2496<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]2497<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2498<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2499<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2500<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2501address from which to load. The pointer must point to a <a
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]2502 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2503marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2504the number or order of execution of this <tt>load</tt> with other
2505volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
2506instructions. </p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2507<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2508<p>The location of memory pointed to is loaded.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2509<h5>Examples:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2510<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2511 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2512 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2513 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2514</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2515</div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2516<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2517<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
2518Instruction</a> </div>
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]2519<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2520<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2521<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]2522 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]2523</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2524<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2525<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2526<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2527<p>There are two arguments to the '<tt>store</tt>' instruction: a value
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2528to 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]2529operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2530operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2531optimizer is not allowed to modify the number or order of execution of
2532this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
2533 href="#i_store">store</a></tt> instructions.</p>
2534<h5>Semantics:</h5>
2535<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
2536at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2537<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2538<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2539 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2540 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2541 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2542</pre>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2543</div>
2544
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2545<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2546<div class="doc_subsubsection">
2547 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
2548</div>
2549
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2550<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2551<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2552<pre>
2553 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
2554</pre>
2555
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2556<h5>Overview:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2557
2558<p>
2559The '<tt>getelementptr</tt>' instruction is used to get the address of a
2560subelement of an aggregate data structure.</p>
2561
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2562<h5>Arguments:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2563
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2564<p>This instruction takes a list of integer operands that indicate what
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2565elements of the aggregate object to index to. The actual types of the arguments
2566provided depend on the type of the first pointer argument. The
2567'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2568levels 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]2569structure, only <tt>i32</tt> integer constants are allowed. When indexing
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2570into an array or pointer, only integers of 32 or 64 bits are allowed, and will
2571be sign extended to 64-bit values.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2572
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2573<p>For example, let's consider a C code fragment and how it gets
2574compiled to LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2575
2576<pre>
2577 struct RT {
2578 char A;
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2579 i32 B[10][20];
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2580 char C;
2581 };
2582 struct ST {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2583 i32 X;
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2584 double Y;
2585 struct RT Z;
2586 };
2587
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2588 define i32 *foo(struct ST *s) {
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2589 return &amp;s[1].Z.B[5][13];
2590 }
2591</pre>
2592
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2593<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2594
2595<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2596 %RT = type { i8 , [10 x [20 x i32]], i8 }
2597 %ST = type { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2598
Brian Gaeke7283e7c2004-07-02 21:08:14 +0000[diff] [blame]2599 implementation
2600
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2601 define i32* %foo(%ST* %s) {
Brian Gaeke7283e7c2004-07-02 21:08:14 +0000[diff] [blame]2602 entry:
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2603 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
2604 ret i32* %reg
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2605 }
2606</pre>
2607
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2608<h5>Semantics:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2609
2610<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2611on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2612and <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]2613<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]2614to 64-bits. <a href="#t_struct">Structure</a> types, require <tt>i32</tt>
Reid Spencer42ddd842006-12-03 16:53:48 +0000[diff] [blame]2615<b>constants</b>.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2616
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2617<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]2618type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2619}</tt>' type, a structure. The second index indexes into the third element of
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2620the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
2621i8 }</tt>' type, another structure. The third index indexes into the second
2622element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2623array. The two dimensions of the array are subscripted into, yielding an
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2624'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
2625to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2626
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2627<p>Note that it is perfectly legal to index partially through a
2628structure, returning a pointer to an inner element. Because of this,
2629the LLVM code for the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2630
2631<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2632 define i32* %foo(%ST* %s) {
2633 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
2634 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
2635 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
2636 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
2637 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
2638 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2639 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2640</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2641
2642<p>Note that it is undefined to access an array out of bounds: array and
2643pointer indexes must always be within the defined bounds of the array type.
2644The one exception for this rules is zero length arrays. These arrays are
2645defined to be accessible as variable length arrays, which requires access
2646beyond the zero'th element.</p>
2647
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2648<p>The getelementptr instruction is often confusing. For some more insight
2649into how it works, see <a href="GetElementPtr.html">the getelementptr
2650FAQ</a>.</p>
2651
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2652<h5>Example:</h5>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2653
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2654<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2655 <i>; yields [12 x i8]*:aptr</i>
2656 %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2657</pre>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2658</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2659
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2660<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]2661<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2662</div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2663<div class="doc_text">
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]2664<p>The instructions in this category are the conversion instructions (casting)
2665which all take a single operand and a type. They perform various bit conversions
2666on the operand.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2667</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2668
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2669<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2670<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2671 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
2672</div>
2673<div class="doc_text">
2674
2675<h5>Syntax:</h5>
2676<pre>
2677 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2678</pre>
2679
2680<h5>Overview:</h5>
2681<p>
2682The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
2683</p>
2684
2685<h5>Arguments:</h5>
2686<p>
2687The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
2688be an <a href="#t_integer">integer</a> type, and a type that specifies the size
2689and type of the result, which must be an <a href="#t_integral">integral</a>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2690type. The bit size of <tt>value</tt> must be larger than the bit size of
2691<tt>ty2</tt>. Equal sized types are not allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2692
2693<h5>Semantics:</h5>
2694<p>
2695The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2696and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
2697larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
2698It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2699
2700<h5>Example:</h5>
2701<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2702 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
2703 %Y = trunc i32 123 to bool <i>; yields bool:true</i>
Reid Spencer5cf0fe42007-01-05 21:33:08 +0000[diff] [blame^]2704 %Y = trunc i32 122 to bool <i>; yields bool:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2705</pre>
2706</div>
2707
2708<!-- _______________________________________________________________________ -->
2709<div class="doc_subsubsection">
2710 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
2711</div>
2712<div class="doc_text">
2713
2714<h5>Syntax:</h5>
2715<pre>
2716 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2717</pre>
2718
2719<h5>Overview:</h5>
2720<p>The '<tt>zext</tt>' instruction zero extends its operand to type
2721<tt>ty2</tt>.</p>
2722
2723
2724<h5>Arguments:</h5>
2725<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
2726<a href="#t_integral">integral</a> type, and a type to cast it to, which must
2727also be of <a href="#t_integral">integral</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2728<tt>value</tt> must be smaller than the bit size of the destination type,
2729<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2730
2731<h5>Semantics:</h5>
2732<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
2733bits until it reaches the size of the destination type, <tt>ty2</tt>. When the
2734the operand and the type are the same size, no bit filling is done and the
2735cast is considered a <i>no-op cast</i> because no bits change (only the type
2736changes).</p>
2737
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2738<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]2739
2740<h5>Example:</h5>
2741<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2742 %X = zext i32 257 to i64 <i>; yields i64:257</i>
2743 %Y = zext bool true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2744</pre>
2745</div>
2746
2747<!-- _______________________________________________________________________ -->
2748<div class="doc_subsubsection">
2749 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
2750</div>
2751<div class="doc_text">
2752
2753<h5>Syntax:</h5>
2754<pre>
2755 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2756</pre>
2757
2758<h5>Overview:</h5>
2759<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
2760
2761<h5>Arguments:</h5>
2762<p>
2763The '<tt>sext</tt>' instruction takes a value to cast, which must be of
2764<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]2765also be of <a href="#t_integral">integral</a> type. The bit size of the
2766<tt>value</tt> must be smaller than the bit size of the destination type,
2767<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2768
2769<h5>Semantics:</h5>
2770<p>
2771The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
2772bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
2773the type <tt>ty2</tt>. When the the operand and the type are the same size,
2774no bit filling is done and the cast is considered a <i>no-op cast</i> because
2775no bits change (only the type changes).</p>
2776
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2777<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]2778
2779<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2780<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2781 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
2782 %Y = sext bool true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2783</pre>
2784</div>
2785
2786<!-- _______________________________________________________________________ -->
2787<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]2788 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
2789</div>
2790
2791<div class="doc_text">
2792
2793<h5>Syntax:</h5>
2794
2795<pre>
2796 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2797</pre>
2798
2799<h5>Overview:</h5>
2800<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
2801<tt>ty2</tt>.</p>
2802
2803
2804<h5>Arguments:</h5>
2805<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
2806 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
2807cast it to. The size of <tt>value</tt> must be larger than the size of
2808<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
2809<i>no-op cast</i>.</p>
2810
2811<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2812<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
2813<a href="#t_floating">floating point</a> type to a smaller
2814<a href="#t_floating">floating point</a> type. If the value cannot fit within
2815the destination type, <tt>ty2</tt>, then the results are undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]2816
2817<h5>Example:</h5>
2818<pre>
2819 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
2820 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
2821</pre>
2822</div>
2823
2824<!-- _______________________________________________________________________ -->
2825<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2826 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
2827</div>
2828<div class="doc_text">
2829
2830<h5>Syntax:</h5>
2831<pre>
2832 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2833</pre>
2834
2835<h5>Overview:</h5>
2836<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
2837floating point value.</p>
2838
2839<h5>Arguments:</h5>
2840<p>The '<tt>fpext</tt>' instruction takes a
2841<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2842and a <a href="#t_floating">floating point</a> type to cast it to. The source
2843type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2844
2845<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2846<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
2847<a href="t_floating">floating point</a> type to a larger
2848<a href="t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
2849used to make a <i>no-op cast</i> because it always changes bits. Use
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2850<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]2851
2852<h5>Example:</h5>
2853<pre>
2854 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
2855 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
2856</pre>
2857</div>
2858
2859<!-- _______________________________________________________________________ -->
2860<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2861 <a name="i_fp2uint">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2862</div>
2863<div class="doc_text">
2864
2865<h5>Syntax:</h5>
2866<pre>
2867 &lt;result&gt; = fp2uint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2868</pre>
2869
2870<h5>Overview:</h5>
2871<p>The '<tt>fp2uint</tt>' converts a floating point <tt>value</tt> to its
2872unsigned integer equivalent of type <tt>ty2</tt>.
2873</p>
2874
2875<h5>Arguments:</h5>
2876<p>The '<tt>fp2uint</tt>' instruction takes a value to cast, which must be a
2877<a href="#t_floating">floating point</a> value, and a type to cast it to, which
2878must be an <a href="#t_integral">integral</a> type.</p>
2879
2880<h5>Semantics:</h5>
2881<p> The '<tt>fp2uint</tt>' instruction converts its
2882<a href="#t_floating">floating point</a> operand into the nearest (rounding
2883towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
2884the results are undefined.</p>
2885
2886<p>When converting to bool, the conversion is done as a comparison against
2887zero. If the <tt>value</tt> was zero, the bool result will be <tt>false</tt>.
2888If the <tt>value</tt> was non-zero, the bool result will be <tt>true</tt>.</p>
2889
2890<h5>Example:</h5>
2891<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2892 %X = fp2uint double 123.0 to i32 <i>; yields i32:123</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2893 %Y = fp2uint float 1.0E+300 to bool <i>; yields bool:true</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2894 %X = fp2uint float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2895</pre>
2896</div>
2897
2898<!-- _______________________________________________________________________ -->
2899<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2900 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2901</div>
2902<div class="doc_text">
2903
2904<h5>Syntax:</h5>
2905<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2906 &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]2907</pre>
2908
2909<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2910<p>The '<tt>fptosi</tt>' instruction converts
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2911<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]2912</p>
2913
2914
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2915<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2916<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]2917<a href="#t_floating">floating point</a> value, and a type to cast it to, which
2918must also be an <a href="#t_integral">integral</a> type.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2919
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2920<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2921<p>The '<tt>fptosi</tt>' instruction converts its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2922<a href="#t_floating">floating point</a> operand into the nearest (rounding
2923towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
2924the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2925
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2926<p>When converting to bool, the conversion is done as a comparison against
2927zero. If the <tt>value</tt> was zero, the bool result will be <tt>false</tt>.
2928If 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]2929
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2930<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2931<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2932 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2933 %Y = fptosi float 1.0E-247 to bool <i>; yields bool:true</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2934 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2935</pre>
2936</div>
2937
2938<!-- _______________________________________________________________________ -->
2939<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2940 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2941</div>
2942<div class="doc_text">
2943
2944<h5>Syntax:</h5>
2945<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2946 &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]2947</pre>
2948
2949<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2950<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2951integer and converts that value to the <tt>ty2</tt> type.</p>
2952
2953
2954<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2955<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]2956<a href="#t_integral">integral</a> value, and a type to cast it to, which must
2957be a <a href="#t_floating">floating point</a> type.</p>
2958
2959<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2960<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2961integer quantity and converts it to the corresponding floating point value. If
2962the value cannot fit in the floating point value, the results are undefined.</p>
2963
2964
2965<h5>Example:</h5>
2966<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2967 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
2968 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2969</pre>
2970</div>
2971
2972<!-- _______________________________________________________________________ -->
2973<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2974 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2975</div>
2976<div class="doc_text">
2977
2978<h5>Syntax:</h5>
2979<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2980 &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]2981</pre>
2982
2983<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2984<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2985integer and converts that value to the <tt>ty2</tt> type.</p>
2986
2987<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2988<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]2989<a href="#t_integral">integral</a> value, and a type to cast it to, which must be
2990a <a href="#t_floating">floating point</a> type.</p>
2991
2992<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2993<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2994integer quantity and converts it to the corresponding floating point value. If
2995the value cannot fit in the floating point value, the results are undefined.</p>
2996
2997<h5>Example:</h5>
2998<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2999 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
3000 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3001</pre>
3002</div>
3003
3004<!-- _______________________________________________________________________ -->
3005<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3006 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3007</div>
3008<div class="doc_text">
3009
3010<h5>Syntax:</h5>
3011<pre>
3012 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3013</pre>
3014
3015<h5>Overview:</h5>
3016<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3017the integer type <tt>ty2</tt>.</p>
3018
3019<h5>Arguments:</h5>
3020<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
3021must be a <a href="t_pointer">pointer</a> value, and a type to cast it to
3022<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
3023
3024<h5>Semantics:</h5>
3025<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3026<tt>ty2</tt> by interpreting the pointer value as an integer and either
3027truncating or zero extending that value to the size of the integer type. If
3028<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3029<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
3030are the same size, then nothing is done (<i>no-op cast</i>).</p>
3031
3032<h5>Example:</h5>
3033<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3034 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit</i>
3035 %Y = ptrtoint i32* %x to i64 <i>; yields zero extend on 32-bit</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3036</pre>
3037</div>
3038
3039<!-- _______________________________________________________________________ -->
3040<div class="doc_subsubsection">
3041 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3042</div>
3043<div class="doc_text">
3044
3045<h5>Syntax:</h5>
3046<pre>
3047 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3048</pre>
3049
3050<h5>Overview:</h5>
3051<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3052a pointer type, <tt>ty2</tt>.</p>
3053
3054<h5>Arguments:</h5>
3055<p>The '<tt>inttoptr</tt>' instruction takes an <a href="i_integer">integer</a>
3056value to cast, and a type to cast it to, which must be a
3057<a href="#t_pointer">pointer</a> type. </tt>
3058
3059<h5>Semantics:</h5>
3060<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3061<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3062the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3063size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3064the size of a pointer then a zero extension is done. If they are the same size,
3065nothing is done (<i>no-op cast</i>).</p>
3066
3067<h5>Example:</h5>
3068<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3069 %X = inttoptr i32 255 to i32* <i>; yields zero extend on 64-bit</i>
3070 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit </i>
3071 %Y = inttoptr i16 0 to i32* <i>; yields zero extend on 32-bit</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3072</pre>
3073</div>
3074
3075<!-- _______________________________________________________________________ -->
3076<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3077 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3078</div>
3079<div class="doc_text">
3080
3081<h5>Syntax:</h5>
3082<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3083 &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]3084</pre>
3085
3086<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3087<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3088<tt>ty2</tt> without changing any bits.</p>
3089
3090<h5>Arguments:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3091<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3092a first class value, and a type to cast it to, which must also be a <a
3093 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
3094and the destination type, <tt>ty2</tt>, must be identical.</p>
3095
3096<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3097<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3098<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3099this conversion. The conversion is done as if the <tt>value</tt> had been
3100stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3101converted to other pointer types with this instruction. To convert pointers to
3102other types, use the <a href="#i_inttoptr">inttoptr</a> or
3103<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3104
3105<h5>Example:</h5>
3106<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3107 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
3108 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
3109 %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3110</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3111</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3112
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3113<!-- ======================================================================= -->
3114<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3115<div class="doc_text">
3116<p>The instructions in this category are the "miscellaneous"
3117instructions, which defy better classification.</p>
3118</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3119
3120<!-- _______________________________________________________________________ -->
3121<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3122</div>
3123<div class="doc_text">
3124<h5>Syntax:</h5>
3125<pre> &lt;result&gt; = icmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
3126</pre>
3127<h5>Overview:</h5>
3128<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
3129of its two integer operands.</p>
3130<h5>Arguments:</h5>
3131<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
3132the condition code which indicates the kind of comparison to perform. It is not
3133a value, just a keyword. The possibilities for the condition code are:
3134<ol>
3135 <li><tt>eq</tt>: equal</li>
3136 <li><tt>ne</tt>: not equal </li>
3137 <li><tt>ugt</tt>: unsigned greater than</li>
3138 <li><tt>uge</tt>: unsigned greater or equal</li>
3139 <li><tt>ult</tt>: unsigned less than</li>
3140 <li><tt>ule</tt>: unsigned less or equal</li>
3141 <li><tt>sgt</tt>: signed greater than</li>
3142 <li><tt>sge</tt>: signed greater or equal</li>
3143 <li><tt>slt</tt>: signed less than</li>
3144 <li><tt>sle</tt>: signed less or equal</li>
3145</ol>
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3146<p>The remaining two arguments must be <a href="#t_integral">integral</a> or
3147<a href="#t_pointer">pointer</a> typed. They must also be identical types.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3148<h5>Semantics:</h5>
3149<p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3150the condition code given as <tt>cond</tt>. The comparison performed always
3151yields a <a href="#t_bool">bool</a> result, as follows:
3152<ol>
3153 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3154 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3155 </li>
3156 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3157 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3158 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3159 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3160 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3161 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3162 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3163 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3164 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3165 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3166 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3167 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3168 <li><tt>sge</tt>: interprets the operands as signed values and yields
3169 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3170 <li><tt>slt</tt>: interprets the operands as signed values and yields
3171 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3172 <li><tt>sle</tt>: interprets the operands as signed values and yields
3173 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3174 </li>
3175</ol>
3176<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
3177values are treated as integers and then compared.</p>
3178<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]3179the vector are compared in turn and the predicate must hold for all
3180elements.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3181
3182<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3183<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3184 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3185 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3186 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3187 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3188 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3189</pre>
3190</div>
3191
3192<!-- _______________________________________________________________________ -->
3193<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3194</div>
3195<div class="doc_text">
3196<h5>Syntax:</h5>
3197<pre> &lt;result&gt; = fcmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
3198</pre>
3199<h5>Overview:</h5>
3200<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3201of its floating point operands.</p>
3202<h5>Arguments:</h5>
3203<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
3204the condition code which indicates the kind of comparison to perform. It is not
3205a value, just a keyword. The possibilities for the condition code are:
3206<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3207 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3208 <li><tt>oeq</tt>: ordered and equal</li>
3209 <li><tt>ogt</tt>: ordered and greater than </li>
3210 <li><tt>oge</tt>: ordered and greater than or equal</li>
3211 <li><tt>olt</tt>: ordered and less than </li>
3212 <li><tt>ole</tt>: ordered and less than or equal</li>
3213 <li><tt>one</tt>: ordered and not equal</li>
3214 <li><tt>ord</tt>: ordered (no nans)</li>
3215 <li><tt>ueq</tt>: unordered or equal</li>
3216 <li><tt>ugt</tt>: unordered or greater than </li>
3217 <li><tt>uge</tt>: unordered or greater than or equal</li>
3218 <li><tt>ult</tt>: unordered or less than </li>
3219 <li><tt>ule</tt>: unordered or less than or equal</li>
3220 <li><tt>une</tt>: unordered or not equal</li>
3221 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3222 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3223</ol>
Reid Spencer93a49852006-12-06 07:08:07 +0000[diff] [blame]3224<p>In the preceding, <i>ordered</i> means that neither operand is a QNAN while
3225<i>unordered</i> means that either operand may be a QNAN.</p>
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3226<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be
3227<a href="#t_floating">floating point</a> typed. They must have identical
3228types.</p>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3229<p>In the foregoing, <i>ordered</i> means that neither operand is a QNAN and
3230<i>unordered</i> means that either operand is a QNAN.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3231<h5>Semantics:</h5>
3232<p>The '<tt>fcmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3233the condition code given as <tt>cond</tt>. The comparison performed always
3234yields a <a href="#t_bool">bool</a> result, as follows:
3235<ol>
3236 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3237 <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]3238 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3239 <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]3240 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3241 <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]3242 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3243 <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]3244 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3245 <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]3246 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3247 <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]3248 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3249 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3250 <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]3251 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3252 <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]3253 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3254 <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]3255 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3256 <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]3257 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3258 <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]3259 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3260 <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]3261 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3262 <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]3263 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3264</ol>
3265<p>If the operands are <a href="#t_packed">packed</a> typed, the elements of
3266the vector are compared in turn and the predicate must hold for all elements.
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3267</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3268
3269<h5>Example:</h5>
3270<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3271 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3272 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3273 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3274</pre>
3275</div>
3276
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3277<!-- _______________________________________________________________________ -->
3278<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
3279Instruction</a> </div>
3280<div class="doc_text">
3281<h5>Syntax:</h5>
3282<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
3283<h5>Overview:</h5>
3284<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
3285the SSA graph representing the function.</p>
3286<h5>Arguments:</h5>
3287<p>The type of the incoming values are specified with the first type
3288field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
3289as arguments, with one pair for each predecessor basic block of the
3290current block. Only values of <a href="#t_firstclass">first class</a>
3291type may be used as the value arguments to the PHI node. Only labels
3292may be used as the label arguments.</p>
3293<p>There must be no non-phi instructions between the start of a basic
3294block and the PHI instructions: i.e. PHI instructions must be first in
3295a basic block.</p>
3296<h5>Semantics:</h5>
3297<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the
3298value specified by the parameter, depending on which basic block we
3299came from in the last <a href="#terminators">terminator</a> instruction.</p>
3300<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3301<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]3302</div>
3303
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3304<!-- _______________________________________________________________________ -->
3305<div class="doc_subsubsection">
3306 <a name="i_select">'<tt>select</tt>' Instruction</a>
3307</div>
3308
3309<div class="doc_text">
3310
3311<h5>Syntax:</h5>
3312
3313<pre>
3314 &lt;result&gt; = select bool &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
3315</pre>
3316
3317<h5>Overview:</h5>
3318
3319<p>
3320The '<tt>select</tt>' instruction is used to choose one value based on a
3321condition, without branching.
3322</p>
3323
3324
3325<h5>Arguments:</h5>
3326
3327<p>
3328The '<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.
3329</p>
3330
3331<h5>Semantics:</h5>
3332
3333<p>
3334If the boolean condition evaluates to true, the instruction returns the first
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3335value argument; otherwise, it returns the second value argument.
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3336</p>
3337
3338<h5>Example:</h5>
3339
3340<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3341 %X = select bool true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3342</pre>
3343</div>
3344
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]3345
3346<!-- _______________________________________________________________________ -->
3347<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3348 <a name="i_call">'<tt>call</tt>' Instruction</a>
3349</div>
3350
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3351<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3352
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3353<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3354<pre>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3355 &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]3356</pre>
3357
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3358<h5>Overview:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3359
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3360<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3361
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3362<h5>Arguments:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3363
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3364<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3365
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3366<ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3367 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3368 <p>The optional "tail" marker indicates whether the callee function accesses
3369 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3370 function call is eligible for tail call optimization. Note that calls may
3371 be marked "tail" even if they do not occur before a <a
3372 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3373 </li>
3374 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3375 <p>The optional "cconv" marker indicates which <a href="callingconv">calling
3376 convention</a> the call should use. If none is specified, the call defaults
3377 to using C calling conventions.
3378 </li>
3379 <li>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3380 <p>'<tt>ty</tt>': shall be the signature of the pointer to function value
3381 being invoked. The argument types must match the types implied by this
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3382 signature. This type can be omitted if the function is not varargs and
3383 if the function type does not return a pointer to a function.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3384 </li>
3385 <li>
3386 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
3387 be invoked. In most cases, this is a direct function invocation, but
3388 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3389 to function value.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3390 </li>
3391 <li>
3392 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencera7e302a2005-05-01 22:22:57 +0000[diff] [blame]3393 function signature argument types. All arguments must be of
3394 <a href="#t_firstclass">first class</a> type. If the function signature
3395 indicates the function accepts a variable number of arguments, the extra
3396 arguments can be specified.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3397 </li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3398</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3399
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3400<h5>Semantics:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3401
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3402<p>The '<tt>call</tt>' instruction is used to cause control flow to
3403transfer to a specified function, with its incoming arguments bound to
3404the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
3405instruction in the called function, control flow continues with the
3406instruction after the function call, and the return value of the
3407function is bound to the result argument. This is a simpler case of
3408the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3409
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3410<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3411
3412<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3413 %retval = call i32 %test(i32 %argc)
3414 call i32(i8 *, ...) *%printf(i8 * %msg, i32 12, i8 42);
3415 %X = tail call i32 %foo()
3416 %Y = tail call <a href="#callingconv">fastcc</a> i32 %foo()
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3417</pre>
3418
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3419</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3420
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3421<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3422<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3423 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3424</div>
3425
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3426<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3427
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3428<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3429
3430<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3431 &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]3432</pre>
3433
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3434<h5>Overview:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3435
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3436<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3437the "variable argument" area of a function call. It is used to implement the
3438<tt>va_arg</tt> macro in C.</p>
3439
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3440<h5>Arguments:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3441
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3442<p>This instruction takes a <tt>va_list*</tt> value and the type of
3443the argument. It returns a value of the specified argument type and
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]3444increments the <tt>va_list</tt> to point to the next argument. Again, the
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3445actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3446
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3447<h5>Semantics:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3448
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3449<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
3450type from the specified <tt>va_list</tt> and causes the
3451<tt>va_list</tt> to point to the next argument. For more information,
3452see the variable argument handling <a href="#int_varargs">Intrinsic
3453Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3454
3455<p>It is legal for this instruction to be called in a function which does not
3456take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3457function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3458
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3459<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3460href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3461argument.</p>
3462
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3463<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3464
3465<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
3466
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3467</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3468
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3469<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3470<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
3471<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3472
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3473<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3474
3475<p>LLVM supports the notion of an "intrinsic function". These functions have
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3476well known names and semantics and are required to follow certain
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3477restrictions. Overall, these instructions represent an extension mechanism for
3478the LLVM language that does not require changing all of the transformations in
3479LLVM to add to the language (or the bytecode reader/writer, the parser,
3480etc...).</p>
3481
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3482<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
3483prefix is reserved in LLVM for intrinsic names; thus, functions may not be named
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3484this. Intrinsic functions must always be external functions: you cannot define
3485the body of intrinsic functions. Intrinsic functions may only be used in call
3486or invoke instructions: it is illegal to take the address of an intrinsic
3487function. Additionally, because intrinsic functions are part of the LLVM
3488language, it is required that they all be documented here if any are added.</p>
3489
3490
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3491<p>To learn how to add an intrinsic function, please see the <a
Chris Lattner590cff32005-05-11 03:35:57 +0000[diff] [blame]3492href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3493</p>
3494
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3495</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3496
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3497<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3498<div class="doc_subsection">
3499 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
3500</div>
3501
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3502<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3503
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3504<p>Variable argument support is defined in LLVM with the <a
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3505 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3506intrinsic functions. These functions are related to the similarly
3507named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3508
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3509<p>All of these functions operate on arguments that use a
3510target-specific value type "<tt>va_list</tt>". The LLVM assembly
3511language reference manual does not define what this type is, so all
3512transformations should be prepared to handle intrinsics with any type
3513used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3514
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]3515<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]3516instruction and the variable argument handling intrinsic functions are
3517used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3518
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3519<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3520define i32 %test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3521 ; Initialize variable argument processing
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3522 %ap = alloca i8 *
3523 call void %<a href="#i_va_start">llvm.va_start</a>(i8 ** %ap)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3524
3525 ; Read a single integer argument
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3526 %tmp = va_arg i8 ** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3527
3528 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3529 %aq = alloca i8 *
3530 call void %<a href="#i_va_copy">llvm.va_copy</a>(i8 ** %aq, i8 ** %ap)
3531 call void %<a href="#i_va_end">llvm.va_end</a>(i8 ** %aq)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3532
3533 ; Stop processing of arguments.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3534 call void %<a href="#i_va_end">llvm.va_end</a>(i8 ** %ap)
3535 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3536}
3537</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3538</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3539
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3540<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3541<div class="doc_subsubsection">
3542 <a name="i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
3543</div>
3544
3545
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3546<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3547<h5>Syntax:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3548<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]3549<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3550<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
3551<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
3552href="#i_va_arg">va_arg</a></tt>.</p>
3553
3554<h5>Arguments:</h5>
3555
3556<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
3557
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3558<h5>Semantics:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3559
3560<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
3561macro available in C. In a target-dependent way, it initializes the
3562<tt>va_list</tt> element the argument points to, so that the next call to
3563<tt>va_arg</tt> will produce the first variable argument passed to the function.
3564Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
3565last argument of the function, the compiler can figure that out.</p>
3566
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3567</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3568
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3569<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3570<div class="doc_subsubsection">
3571 <a name="i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
3572</div>
3573
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3574<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3575<h5>Syntax:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3576<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]3577<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3578<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>&lt;arglist&gt;</tt>
3579which has been initialized previously with <tt><a href="#i_va_start">llvm.va_start</a></tt>
3580or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3581<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3582<p>The argument is a <tt>va_list</tt> to destroy.</p>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3583<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3584<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]3585macro available in C. In a target-dependent way, it destroys the <tt>va_list</tt>.
3586Calls to <a href="#i_va_start"><tt>llvm.va_start</tt></a> and <a
3587 href="#i_va_copy"><tt>llvm.va_copy</tt></a> must be matched exactly
3588with calls to <tt>llvm.va_end</tt>.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3589</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3590
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3591<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3592<div class="doc_subsubsection">
3593 <a name="i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
3594</div>
3595
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3596<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3597
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3598<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3599
3600<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3601 declare void %llvm.va_copy(&lt;va_list&gt;* &lt;destarglist&gt;,
Andrew Lenharthd0a4c622005-06-22 20:38:11 +0000[diff] [blame]3602 &lt;va_list&gt;* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3603</pre>
3604
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3605<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3606
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3607<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position from
3608the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3609
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3610<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3611
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3612<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]3613The 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]3614
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3615
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3616<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3617
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3618<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt> macro
3619available in C. In a target-dependent way, it copies the source
3620<tt>va_list</tt> element into the destination list. This intrinsic is necessary
3621because 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]3622arbitrarily complex and require memory allocation, for example.</p>
3623
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3624</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3625
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3626<!-- ======================================================================= -->
3627<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3628 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
3629</div>
3630
3631<div class="doc_text">
3632
3633<p>
3634LLVM support for <a href="GarbageCollection.html">Accurate Garbage
3635Collection</a> requires the implementation and generation of these intrinsics.
3636These intrinsics allow identification of <a href="#i_gcroot">GC roots on the
3637stack</a>, as well as garbage collector implementations that require <a
3638href="#i_gcread">read</a> and <a href="#i_gcwrite">write</a> barriers.
3639Front-ends for type-safe garbage collected languages should generate these
3640intrinsics to make use of the LLVM garbage collectors. For more details, see <a
3641href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
3642</p>
3643</div>
3644
3645<!-- _______________________________________________________________________ -->
3646<div class="doc_subsubsection">
3647 <a name="i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
3648</div>
3649
3650<div class="doc_text">
3651
3652<h5>Syntax:</h5>
3653
3654<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]3655 declare void %llvm.gcroot(&lt;ty&gt;** %ptrloc, &lt;ty2&gt;* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3656</pre>
3657
3658<h5>Overview:</h5>
3659
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]3660<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]3661the code generator, and allows some metadata to be associated with it.</p>
3662
3663<h5>Arguments:</h5>
3664
3665<p>The first argument specifies the address of a stack object that contains the
3666root pointer. The second pointer (which must be either a constant or a global
3667value address) contains the meta-data to be associated with the root.</p>
3668
3669<h5>Semantics:</h5>
3670
3671<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
3672location. At compile-time, the code generator generates information to allow
3673the runtime to find the pointer at GC safe points.
3674</p>
3675
3676</div>
3677
3678
3679<!-- _______________________________________________________________________ -->
3680<div class="doc_subsubsection">
3681 <a name="i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
3682</div>
3683
3684<div class="doc_text">
3685
3686<h5>Syntax:</h5>
3687
3688<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3689 declare i8 * %llvm.gcread(i8 * %ObjPtr, i8 ** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3690</pre>
3691
3692<h5>Overview:</h5>
3693
3694<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
3695locations, allowing garbage collector implementations that require read
3696barriers.</p>
3697
3698<h5>Arguments:</h5>
3699
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3700<p>The second argument is the address to read from, which should be an address
3701allocated from the garbage collector. The first object is a pointer to the
3702start of the referenced object, if needed by the language runtime (otherwise
3703null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3704
3705<h5>Semantics:</h5>
3706
3707<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
3708instruction, but may be replaced with substantially more complex code by the
3709garbage collector runtime, as needed.</p>
3710
3711</div>
3712
3713
3714<!-- _______________________________________________________________________ -->
3715<div class="doc_subsubsection">
3716 <a name="i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
3717</div>
3718
3719<div class="doc_text">
3720
3721<h5>Syntax:</h5>
3722
3723<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3724 declare void %llvm.gcwrite(i8 * %P1, i8 * %Obj, i8 ** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3725</pre>
3726
3727<h5>Overview:</h5>
3728
3729<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
3730locations, allowing garbage collector implementations that require write
3731barriers (such as generational or reference counting collectors).</p>
3732
3733<h5>Arguments:</h5>
3734
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3735<p>The first argument is the reference to store, the second is the start of the
3736object to store it to, and the third is the address of the field of Obj to
3737store to. If the runtime does not require a pointer to the object, Obj may be
3738null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3739
3740<h5>Semantics:</h5>
3741
3742<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
3743instruction, but may be replaced with substantially more complex code by the
3744garbage collector runtime, as needed.</p>
3745
3746</div>
3747
3748
3749
3750<!-- ======================================================================= -->
3751<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3752 <a name="int_codegen">Code Generator Intrinsics</a>
3753</div>
3754
3755<div class="doc_text">
3756<p>
3757These intrinsics are provided by LLVM to expose special features that may only
3758be implemented with code generator support.
3759</p>
3760
3761</div>
3762
3763<!-- _______________________________________________________________________ -->
3764<div class="doc_subsubsection">
3765 <a name="i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
3766</div>
3767
3768<div class="doc_text">
3769
3770<h5>Syntax:</h5>
3771<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3772 declare i8 *%llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3773</pre>
3774
3775<h5>Overview:</h5>
3776
3777<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]3778The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
3779target-specific value indicating the return address of the current function
3780or one of its callers.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3781</p>
3782
3783<h5>Arguments:</h5>
3784
3785<p>
3786The argument to this intrinsic indicates which function to return the address
3787for. Zero indicates the calling function, one indicates its caller, etc. The
3788argument is <b>required</b> to be a constant integer value.
3789</p>
3790
3791<h5>Semantics:</h5>
3792
3793<p>
3794The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
3795the return address of the specified call frame, or zero if it cannot be
3796identified. The value returned by this intrinsic is likely to be incorrect or 0
3797for arguments other than zero, so it should only be used for debugging purposes.
3798</p>
3799
3800<p>
3801Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]3802aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3803source-language caller.
3804</p>
3805</div>
3806
3807
3808<!-- _______________________________________________________________________ -->
3809<div class="doc_subsubsection">
3810 <a name="i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
3811</div>
3812
3813<div class="doc_text">
3814
3815<h5>Syntax:</h5>
3816<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3817 declare i8 *%llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3818</pre>
3819
3820<h5>Overview:</h5>
3821
3822<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]3823The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
3824target-specific frame pointer value for the specified stack frame.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3825</p>
3826
3827<h5>Arguments:</h5>
3828
3829<p>
3830The argument to this intrinsic indicates which function to return the frame
3831pointer for. Zero indicates the calling function, one indicates its caller,
3832etc. The argument is <b>required</b> to be a constant integer value.
3833</p>
3834
3835<h5>Semantics:</h5>
3836
3837<p>
3838The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
3839the frame address of the specified call frame, or zero if it cannot be
3840identified. The value returned by this intrinsic is likely to be incorrect or 0
3841for arguments other than zero, so it should only be used for debugging purposes.
3842</p>
3843
3844<p>
3845Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]3846aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3847source-language caller.
3848</p>
3849</div>
3850
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3851<!-- _______________________________________________________________________ -->
3852<div class="doc_subsubsection">
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]3853 <a name="i_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
3854</div>
3855
3856<div class="doc_text">
3857
3858<h5>Syntax:</h5>
3859<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3860 declare i8 *%llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]3861</pre>
3862
3863<h5>Overview:</h5>
3864
3865<p>
3866The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
3867the function stack, for use with <a href="#i_stackrestore">
3868<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
3869features like scoped automatic variable sized arrays in C99.
3870</p>
3871
3872<h5>Semantics:</h5>
3873
3874<p>
3875This intrinsic returns a opaque pointer value that can be passed to <a
3876href="#i_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
3877<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
3878<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
3879state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
3880practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
3881that were allocated after the <tt>llvm.stacksave</tt> was executed.
3882</p>
3883
3884</div>
3885
3886<!-- _______________________________________________________________________ -->
3887<div class="doc_subsubsection">
3888 <a name="i_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
3889</div>
3890
3891<div class="doc_text">
3892
3893<h5>Syntax:</h5>
3894<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3895 declare void %llvm.stackrestore(i8 * %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]3896</pre>
3897
3898<h5>Overview:</h5>
3899
3900<p>
3901The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
3902the function stack to the state it was in when the corresponding <a
3903href="#llvm.stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
3904useful for implementing language features like scoped automatic variable sized
3905arrays in C99.
3906</p>
3907
3908<h5>Semantics:</h5>
3909
3910<p>
3911See the description for <a href="#i_stacksave"><tt>llvm.stacksave</tt></a>.
3912</p>
3913
3914</div>
3915
3916
3917<!-- _______________________________________________________________________ -->
3918<div class="doc_subsubsection">
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3919 <a name="i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
3920</div>
3921
3922<div class="doc_text">
3923
3924<h5>Syntax:</h5>
3925<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3926 declare void %llvm.prefetch(i8 * &lt;address&gt;,
3927 i32 &lt;rw&gt;, i32 &lt;locality&gt;)
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3928</pre>
3929
3930<h5>Overview:</h5>
3931
3932
3933<p>
3934The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3935a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
3936no
3937effect on the behavior of the program but can change its performance
Chris Lattner2a615362005-02-28 19:47:14 +0000[diff] [blame]3938characteristics.
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3939</p>
3940
3941<h5>Arguments:</h5>
3942
3943<p>
3944<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
3945determining if the fetch should be for a read (0) or write (1), and
3946<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattneraeffb4a2005-03-07 20:31:38 +0000[diff] [blame]3947locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3948<tt>locality</tt> arguments must be constant integers.
3949</p>
3950
3951<h5>Semantics:</h5>
3952
3953<p>
3954This intrinsic does not modify the behavior of the program. In particular,
3955prefetches cannot trap and do not produce a value. On targets that support this
3956intrinsic, the prefetch can provide hints to the processor cache for better
3957performance.
3958</p>
3959
3960</div>
3961
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]3962<!-- _______________________________________________________________________ -->
3963<div class="doc_subsubsection">
3964 <a name="i_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
3965</div>
3966
3967<div class="doc_text">
3968
3969<h5>Syntax:</h5>
3970<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3971 declare void %llvm.pcmarker( i32 &lt;id&gt; )
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]3972</pre>
3973
3974<h5>Overview:</h5>
3975
3976
3977<p>
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3978The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
3979(PC) in a region of
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]3980code to simulators and other tools. The method is target specific, but it is
3981expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]3982The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnerd07c3f42005-11-15 06:07:55 +0000[diff] [blame]3983after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb3e7afd2006-03-24 07:16:10 +0000[diff] [blame]3984optimizations. The intended use is to be inserted after optimizations to allow
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3985correlations of simulation runs.
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]3986</p>
3987
3988<h5>Arguments:</h5>
3989
3990<p>
3991<tt>id</tt> is a numerical id identifying the marker.
3992</p>
3993
3994<h5>Semantics:</h5>
3995
3996<p>
3997This intrinsic does not modify the behavior of the program. Backends that do not
3998support this intrinisic may ignore it.
3999</p>
4000
4001</div>
4002
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4003<!-- _______________________________________________________________________ -->
4004<div class="doc_subsubsection">
4005 <a name="i_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
4006</div>
4007
4008<div class="doc_text">
4009
4010<h5>Syntax:</h5>
4011<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4012 declare i64 %llvm.readcyclecounter( )
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4013</pre>
4014
4015<h5>Overview:</h5>
4016
4017
4018<p>
4019The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
4020counter register (or similar low latency, high accuracy clocks) on those targets
4021that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
4022As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
4023should only be used for small timings.
4024</p>
4025
4026<h5>Semantics:</h5>
4027
4028<p>
4029When directly supported, reading the cycle counter should not modify any memory.
4030Implementations are allowed to either return a application specific value or a
4031system wide value. On backends without support, this is lowered to a constant 0.
4032</p>
4033
4034</div>
4035
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4036<!-- ======================================================================= -->
4037<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4038 <a name="int_libc">Standard C Library Intrinsics</a>
4039</div>
4040
4041<div class="doc_text">
4042<p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4043LLVM provides intrinsics for a few important standard C library functions.
4044These intrinsics allow source-language front-ends to pass information about the
4045alignment of the pointer arguments to the code generator, providing opportunity
4046for more efficient code generation.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4047</p>
4048
4049</div>
4050
4051<!-- _______________________________________________________________________ -->
4052<div class="doc_subsubsection">
4053 <a name="i_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
4054</div>
4055
4056<div class="doc_text">
4057
4058<h5>Syntax:</h5>
4059<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4060 declare void %llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4061 i32 &lt;len&gt;, i32 &lt;align&gt;)
4062 declare void %llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4063 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4064</pre>
4065
4066<h5>Overview:</h5>
4067
4068<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4069The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4070location to the destination location.
4071</p>
4072
4073<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4074Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4075intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4076</p>
4077
4078<h5>Arguments:</h5>
4079
4080<p>
4081The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4082the source. The third argument is an integer argument
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4083specifying the number of bytes to copy, and the fourth argument is the alignment
4084of the source and destination locations.
4085</p>
4086
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4087<p>
4088If 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]4089the caller guarantees that both the source and destination pointers are aligned
4090to that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4091</p>
4092
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4093<h5>Semantics:</h5>
4094
4095<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4096The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4097location to the destination location, which are not allowed to overlap. It
4098copies "len" bytes of memory over. If the argument is known to be aligned to
4099some boundary, this can be specified as the fourth argument, otherwise it should
4100be set to 0 or 1.
4101</p>
4102</div>
4103
4104
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4105<!-- _______________________________________________________________________ -->
4106<div class="doc_subsubsection">
4107 <a name="i_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
4108</div>
4109
4110<div class="doc_text">
4111
4112<h5>Syntax:</h5>
4113<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4114 declare void %llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4115 i32 &lt;len&gt;, i32 &lt;align&gt;)
4116 declare void %llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4117 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4118</pre>
4119
4120<h5>Overview:</h5>
4121
4122<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4123The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
4124location to the destination location. It is similar to the
4125'<tt>llvm.memcmp</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4126</p>
4127
4128<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4129Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
4130intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4131</p>
4132
4133<h5>Arguments:</h5>
4134
4135<p>
4136The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4137the source. The third argument is an integer argument
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4138specifying the number of bytes to copy, and the fourth argument is the alignment
4139of the source and destination locations.
4140</p>
4141
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4142<p>
4143If 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]4144the caller guarantees that the source and destination pointers are aligned to
4145that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4146</p>
4147
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4148<h5>Semantics:</h5>
4149
4150<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4151The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4152location to the destination location, which may overlap. It
4153copies "len" bytes of memory over. If the argument is known to be aligned to
4154some boundary, this can be specified as the fourth argument, otherwise it should
4155be set to 0 or 1.
4156</p>
4157</div>
4158
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4159
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4160<!-- _______________________________________________________________________ -->
4161<div class="doc_subsubsection">
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4162 <a name="i_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4163</div>
4164
4165<div class="doc_text">
4166
4167<h5>Syntax:</h5>
4168<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4169 declare void %llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
4170 i32 &lt;len&gt;, i32 &lt;align&gt;)
4171 declare void %llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
4172 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4173</pre>
4174
4175<h5>Overview:</h5>
4176
4177<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4178The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4179byte value.
4180</p>
4181
4182<p>
4183Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
4184does not return a value, and takes an extra alignment argument.
4185</p>
4186
4187<h5>Arguments:</h5>
4188
4189<p>
4190The first argument is a pointer to the destination to fill, the second is the
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4191byte value to fill it with, the third argument is an integer
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4192argument specifying the number of bytes to fill, and the fourth argument is the
4193known alignment of destination location.
4194</p>
4195
4196<p>
4197If 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]4198the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4199</p>
4200
4201<h5>Semantics:</h5>
4202
4203<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4204The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
4205the
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4206destination location. If the argument is known to be aligned to some boundary,
4207this can be specified as the fourth argument, otherwise it should be set to 0 or
42081.
4209</p>
4210</div>
4211
4212
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4213<!-- _______________________________________________________________________ -->
4214<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4215 <a name="i_isunordered">'<tt>llvm.isunordered.*</tt>' Intrinsic</a>
Alkis Evlogimenos26bbe932004-06-13 01:16:15 +0000[diff] [blame]4216</div>
4217
4218<div class="doc_text">
4219
4220<h5>Syntax:</h5>
4221<pre>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4222 declare bool %llvm.isunordered.f32(float Val1, float Val2)
4223 declare bool %llvm.isunordered.f64(double Val1, double Val2)
Alkis Evlogimenos26bbe932004-06-13 01:16:15 +0000[diff] [blame]4224</pre>
4225
4226<h5>Overview:</h5>
4227
4228<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4229The '<tt>llvm.isunordered</tt>' intrinsics return true if either or both of the
Alkis Evlogimenos26bbe932004-06-13 01:16:15 +0000[diff] [blame]4230specified floating point values is a NAN.
4231</p>
4232
4233<h5>Arguments:</h5>
4234
4235<p>
4236The arguments are floating point numbers of the same type.
4237</p>
4238
4239<h5>Semantics:</h5>
4240
4241<p>
4242If either or both of the arguments is a SNAN or QNAN, it returns true, otherwise
4243false.
4244</p>
4245</div>
4246
4247
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4248<!-- _______________________________________________________________________ -->
4249<div class="doc_subsubsection">
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4250 <a name="i_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4251</div>
4252
4253<div class="doc_text">
4254
4255<h5>Syntax:</h5>
4256<pre>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4257 declare float %llvm.sqrt.f32(float %Val)
4258 declare double %llvm.sqrt.f64(double %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4259</pre>
4260
4261<h5>Overview:</h5>
4262
4263<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4264The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4265returning the same value as the libm '<tt>sqrt</tt>' function would. Unlike
4266<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
4267negative numbers (which allows for better optimization).
4268</p>
4269
4270<h5>Arguments:</h5>
4271
4272<p>
4273The argument and return value are floating point numbers of the same type.
4274</p>
4275
4276<h5>Semantics:</h5>
4277
4278<p>
4279This function returns the sqrt of the specified operand if it is a positive
4280floating point number.
4281</p>
4282</div>
4283
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4284<!-- _______________________________________________________________________ -->
4285<div class="doc_subsubsection">
4286 <a name="i_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
4287</div>
4288
4289<div class="doc_text">
4290
4291<h5>Syntax:</h5>
4292<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4293 declare float %llvm.powi.f32(float %Val, i32 %power)
4294 declare double %llvm.powi.f64(double %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4295</pre>
4296
4297<h5>Overview:</h5>
4298
4299<p>
4300The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
4301specified (positive or negative) power. The order of evaluation of
4302multiplications is not defined.
4303</p>
4304
4305<h5>Arguments:</h5>
4306
4307<p>
4308The second argument is an integer power, and the first is a value to raise to
4309that power.
4310</p>
4311
4312<h5>Semantics:</h5>
4313
4314<p>
4315This function returns the first value raised to the second power with an
4316unspecified sequence of rounding operations.</p>
4317</div>
4318
4319
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4320<!-- ======================================================================= -->
4321<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4322 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4323</div>
4324
4325<div class="doc_text">
4326<p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4327LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4328These allow efficient code generation for some algorithms.
4329</p>
4330
4331</div>
4332
4333<!-- _______________________________________________________________________ -->
4334<div class="doc_subsubsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4335 <a name="i_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
4336</div>
4337
4338<div class="doc_text">
4339
4340<h5>Syntax:</h5>
4341<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4342 declare i16 %llvm.bswap.i16(i16 &lt;id&gt;)
4343 declare i32 %llvm.bswap.i32(i32 &lt;id&gt;)
4344 declare i64 %llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4345</pre>
4346
4347<h5>Overview:</h5>
4348
4349<p>
4350The '<tt>llvm.bwsap</tt>' family of intrinsics is used to byteswap a 16, 32 or
435164 bit quantity. These are useful for performing operations on data that is not
4352in the target's native byte order.
4353</p>
4354
4355<h5>Semantics:</h5>
4356
4357<p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4358The <tt>llvm.bswap.16</tt> intrinsic returns an i16 value that has the high
4359and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
4360intrinsic returns an i32 value that has the four bytes of the input i32
4361swapped, so that if the input bytes are numbered 0, 1, 2, 3 then the returned
4362i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i64</tt>
4363intrinsic extends this concept to 64 bits.
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4364</p>
4365
4366</div>
4367
4368<!-- _______________________________________________________________________ -->
4369<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4370 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4371</div>
4372
4373<div class="doc_text">
4374
4375<h5>Syntax:</h5>
4376<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4377 declare i8 %llvm.ctpop.i8 (i8 &lt;src&gt;)
4378 declare i16 %llvm.ctpop.i16(i16 &lt;src&gt;)
4379 declare i32 %llvm.ctpop.i32(i32 &lt;src&gt;)
4380 declare i64 %llvm.ctpop.i64(i64 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4381</pre>
4382
4383<h5>Overview:</h5>
4384
4385<p>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4386The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
4387value.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4388</p>
4389
4390<h5>Arguments:</h5>
4391
4392<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]4393The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4394integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4395</p>
4396
4397<h5>Semantics:</h5>
4398
4399<p>
4400The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
4401</p>
4402</div>
4403
4404<!-- _______________________________________________________________________ -->
4405<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]4406 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4407</div>
4408
4409<div class="doc_text">
4410
4411<h5>Syntax:</h5>
4412<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4413 declare i8 %llvm.ctlz.i8 (i8 &lt;src&gt;)
4414 declare i16 %llvm.ctlz.i16(i16 &lt;src&gt;)
4415 declare i32 %llvm.ctlz.i32(i32 &lt;src&gt;)
4416 declare i64 %llvm.ctlz.i64(i64 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4417</pre>
4418
4419<h5>Overview:</h5>
4420
4421<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4422The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
4423leading zeros in a variable.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4424</p>
4425
4426<h5>Arguments:</h5>
4427
4428<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]4429The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4430integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4431</p>
4432
4433<h5>Semantics:</h5>
4434
4435<p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4436The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
4437in 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]4438of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4439</p>
4440</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4441
4442
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4443
4444<!-- _______________________________________________________________________ -->
4445<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]4446 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4447</div>
4448
4449<div class="doc_text">
4450
4451<h5>Syntax:</h5>
4452<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4453 declare i8 %llvm.cttz.i8 (i8 &lt;src&gt;)
4454 declare i16 %llvm.cttz.i16(i16 &lt;src&gt;)
4455 declare i32 %llvm.cttz.i32(i32 &lt;src&gt;)
4456 declare i64 %llvm.cttz.i64(i64 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4457</pre>
4458
4459<h5>Overview:</h5>
4460
4461<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4462The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
4463trailing zeros.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4464</p>
4465
4466<h5>Arguments:</h5>
4467
4468<p>
4469The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4470integer type. The return type must match the argument type.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4471</p>
4472
4473<h5>Semantics:</h5>
4474
4475<p>
4476The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
4477in a variable. If the src == 0 then the result is the size in bits of the type
4478of src. For example, <tt>llvm.cttz(2) = 1</tt>.
4479</p>
4480</div>
4481
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4482<!-- ======================================================================= -->
4483<div class="doc_subsection">
4484 <a name="int_debugger">Debugger Intrinsics</a>
4485</div>
4486
4487<div class="doc_text">
4488<p>
4489The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
4490are described in the <a
4491href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
4492Debugging</a> document.
4493</p>
4494</div>
4495
4496
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4497<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4498<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]4499<address>
4500 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
4501 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
4502 <a href="http://validator.w3.org/check/referer"><img
4503 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!" /></a>
4504
4505 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]4506 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]4507 Last modified: $Date$
4508</address>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4509</body>
4510</html>