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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 3b19d65897db69f1ce2f91bcd581ab76d1c880cf / . / 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.">
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11</head>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]14
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]15<div class="doc_title"> LLVM Language Reference Manual </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a></li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]24 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]25 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]26 <li><a href="#functionstructure">Functions</a></li>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]27 <li><a href="#paramattrs">Parameter Attributes</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]28 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]29 </ol>
30 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]31 <li><a href="#typesystem">Type System</a>
32 <ol>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]33 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]34 <ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]35 <li><a href="#t_classifications">Type Classifications</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]36 </ol>
37 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]38 <li><a href="#t_derived">Derived Types</a>
39 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]40 <li><a href="#t_array">Array Type</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]41 <li><a href="#t_function">Function Type</a></li>
42 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]43 <li><a href="#t_struct">Structure Type</a></li>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]44 <li><a href="#t_pstruct">Packed Structure Type</a></li>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]45 <li><a href="#t_packed">Packed Type</a></li>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]46 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]47 </ol>
48 </li>
49 </ol>
50 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]51 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]52 <ol>
53 <li><a href="#simpleconstants">Simple Constants</a>
54 <li><a href="#aggregateconstants">Aggregate Constants</a>
55 <li><a href="#globalconstants">Global Variable and Function Addresses</a>
56 <li><a href="#undefvalues">Undefined Values</a>
57 <li><a href="#constantexprs">Constant Expressions</a>
58 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]59 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]60 <li><a href="#othervalues">Other Values</a>
61 <ol>
62 <li><a href="#inlineasm">Inline Assembler Expressions</a>
63 </ol>
64 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]65 <li><a href="#instref">Instruction Reference</a>
66 <ol>
67 <li><a href="#terminators">Terminator Instructions</a>
68 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]69 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
70 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]71 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
72 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]73 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]74 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]75 </ol>
76 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]77 <li><a href="#binaryops">Binary Operations</a>
78 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]79 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
80 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
81 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]82 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
83 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
84 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]85 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
86 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
87 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]88 </ol>
89 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]90 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
91 <ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]92 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]93 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]94 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
95 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]96 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
97 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]98 </ol>
99 </li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]100 <li><a href="#vectorops">Vector Operations</a>
101 <ol>
102 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
103 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
104 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]105 </ol>
106 </li>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]107 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]108 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]109 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
110 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
111 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]112 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
113 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
114 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]115 </ol>
116 </li>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]117 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]118 <ol>
119 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
120 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
121 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
122 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
123 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]124 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
125 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
126 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
127 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]128 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
129 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]130 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]131 </ol>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]132 <li><a href="#otherops">Other Operations</a>
133 <ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]134 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
135 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]136 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]137 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]138 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]139 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]140 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]141 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]142 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]143 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]144 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]145 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]146 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
147 <ol>
148 <li><a href="#i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
149 <li><a href="#i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
150 <li><a href="#i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
151 </ol>
152 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]153 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
154 <ol>
155 <li><a href="#i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
156 <li><a href="#i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
157 <li><a href="#i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
158 </ol>
159 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]160 <li><a href="#int_codegen">Code Generator Intrinsics</a>
161 <ol>
162 <li><a href="#i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
163 <li><a href="#i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]164 <li><a href="#i_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
165 <li><a href="#i_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]166 <li><a href="#i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]167 <li><a href="#i_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]168 <li><a href="#i_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]169 </ol>
170 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]171 <li><a href="#int_libc">Standard C Library Intrinsics</a>
172 <ol>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]173 <li><a href="#i_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
174 <li><a href="#i_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
175 <li><a href="#i_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]176 <li><a href="#i_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]177 <li><a href="#i_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]178 </ol>
179 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]180 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]181 <ol>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]182 <li><a href="#i_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]183 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
184 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
185 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]186 </ol>
187 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]188 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]189 </ol>
190 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]191</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]192
193<div class="doc_author">
194 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
195 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]196</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]197
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]198<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]199<div class="doc_section"> <a name="abstract">Abstract </a></div>
200<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]201
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]202<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]203<p>This document is a reference manual for the LLVM assembly language.
204LLVM is an SSA based representation that provides type safety,
205low-level operations, flexibility, and the capability of representing
206'all' high-level languages cleanly. It is the common code
207representation used throughout all phases of the LLVM compilation
208strategy.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]209</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]210
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]211<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]212<div class="doc_section"> <a name="introduction">Introduction</a> </div>
213<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]214
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]215<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]216
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]217<p>The LLVM code representation is designed to be used in three
218different forms: as an in-memory compiler IR, as an on-disk bytecode
219representation (suitable for fast loading by a Just-In-Time compiler),
220and as a human readable assembly language representation. This allows
221LLVM to provide a powerful intermediate representation for efficient
222compiler transformations and analysis, while providing a natural means
223to debug and visualize the transformations. The three different forms
224of LLVM are all equivalent. This document describes the human readable
225representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]226
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]227<p>The LLVM representation aims to be light-weight and low-level
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]228while being expressive, typed, and extensible at the same time. It
229aims to be a "universal IR" of sorts, by being at a low enough level
230that high-level ideas may be cleanly mapped to it (similar to how
231microprocessors are "universal IR's", allowing many source languages to
232be mapped to them). By providing type information, LLVM can be used as
233the target of optimizations: for example, through pointer analysis, it
234can be proven that a C automatic variable is never accessed outside of
235the current function... allowing it to be promoted to a simple SSA
236value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]237
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]238</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]239
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]240<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]241<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]242
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]243<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]244
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]245<p>It is important to note that this document describes 'well formed'
246LLVM assembly language. There is a difference between what the parser
247accepts and what is considered 'well formed'. For example, the
248following instruction is syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]249
250<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]251 %x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]252</pre>
253
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]254<p>...because the definition of <tt>%x</tt> does not dominate all of
255its uses. The LLVM infrastructure provides a verification pass that may
256be used to verify that an LLVM module is well formed. This pass is
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]257automatically run by the parser after parsing input assembly and by
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]258the optimizer before it outputs bytecode. The violations pointed out
259by the verifier pass indicate bugs in transformation passes or input to
260the parser.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]261
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]262<!-- Describe the typesetting conventions here. --> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]263
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]264<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]265<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]266<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]267
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]268<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]269
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]270<p>LLVM uses three different forms of identifiers, for different
271purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]272
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]273<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]274 <li>Named values are represented as a string of characters with a '%' prefix.
275 For example, %foo, %DivisionByZero, %a.really.long.identifier. The actual
276 regular expression used is '<tt>%[a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
277 Identifiers which require other characters in their names can be surrounded
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]278 with quotes. In this way, anything except a <tt>&quot;</tt> character can be used
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]279 in a name.</li>
280
281 <li>Unnamed values are represented as an unsigned numeric value with a '%'
282 prefix. For example, %12, %2, %44.</li>
283
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]284 <li>Constants, which are described in a <a href="#constants">section about
285 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]286</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]287
288<p>LLVM requires that values start with a '%' sign for two reasons: Compilers
289don't need to worry about name clashes with reserved words, and the set of
290reserved words may be expanded in the future without penalty. Additionally,
291unnamed identifiers allow a compiler to quickly come up with a temporary
292variable without having to avoid symbol table conflicts.</p>
293
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]294<p>Reserved words in LLVM are very similar to reserved words in other
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]295languages. There are keywords for different opcodes
296('<tt><a href="#i_add">add</a></tt>',
297 '<tt><a href="#i_bitcast">bitcast</a></tt>',
298 '<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]299href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]300and others. These reserved words cannot conflict with variable names, because
301none of them start with a '%' character.</p>
302
303<p>Here is an example of LLVM code to multiply the integer variable
304'<tt>%X</tt>' by 8:</p>
305
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]306<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]307
308<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]309 %result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]310</pre>
311
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]312<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]313
314<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]315 %result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]316</pre>
317
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]318<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]319
320<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]321 <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
322 <a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
323 %result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]324</pre>
325
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]326<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
327important lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]328
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]329<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]330
331 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
332 line.</li>
333
334 <li>Unnamed temporaries are created when the result of a computation is not
335 assigned to a named value.</li>
336
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]337 <li>Unnamed temporaries are numbered sequentially</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]338
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]339</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]340
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]341<p>...and it also shows a convention that we follow in this document. When
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]342demonstrating instructions, we will follow an instruction with a comment that
343defines the type and name of value produced. Comments are shown in italic
344text.</p>
345
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]346</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]347
348<!-- *********************************************************************** -->
349<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
350<!-- *********************************************************************** -->
351
352<!-- ======================================================================= -->
353<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
354</div>
355
356<div class="doc_text">
357
358<p>LLVM programs are composed of "Module"s, each of which is a
359translation unit of the input programs. Each module consists of
360functions, global variables, and symbol table entries. Modules may be
361combined together with the LLVM linker, which merges function (and
362global variable) definitions, resolves forward declarations, and merges
363symbol table entries. Here is an example of the "hello world" module:</p>
364
365<pre><i>; Declare the string constant as a global constant...</i>
366<a href="#identifiers">%.LC0</a> = <a href="#linkage_internal">internal</a> <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]367 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]368
369<i>; External declaration of the puts function</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]370<a href="#functionstructure">declare</a> i32 %puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]371
Chris Lattner81c01f02006-06-13 03:05:47 +0000[diff] [blame]372<i>; Global variable / Function body section separator</i>
373implementation
374
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]375<i>; Definition of main function</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]376define i32 %main() { <i>; i32()* </i>
377 <i>; Convert [13x i8 ]* to i8 *...</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]378 %cast210 = <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]379 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]380
381 <i>; Call puts function to write out the string to stdout...</i>
382 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]383 href="#i_call">call</a> i32 %puts(i8 * %cast210) <i>; i32</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]384 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]385 href="#i_ret">ret</a> i32 0<br>}<br></pre>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]386
387<p>This example is made up of a <a href="#globalvars">global variable</a>
388named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
389function, and a <a href="#functionstructure">function definition</a>
390for "<tt>main</tt>".</p>
391
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]392<p>In general, a module is made up of a list of global values,
393where both functions and global variables are global values. Global values are
394represented by a pointer to a memory location (in this case, a pointer to an
395array of char, and a pointer to a function), and have one of the following <a
396href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]397
Chris Lattner81c01f02006-06-13 03:05:47 +0000[diff] [blame]398<p>Due to a limitation in the current LLVM assembly parser (it is limited by
399one-token lookahead), modules are split into two pieces by the "implementation"
400keyword. Global variable prototypes and definitions must occur before the
401keyword, and function definitions must occur after it. Function prototypes may
402occur either before or after it. In the future, the implementation keyword may
403become a noop, if the parser gets smarter.</p>
404
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]405</div>
406
407<!-- ======================================================================= -->
408<div class="doc_subsection">
409 <a name="linkage">Linkage Types</a>
410</div>
411
412<div class="doc_text">
413
414<p>
415All Global Variables and Functions have one of the following types of linkage:
416</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]417
418<dl>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]419
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]420 <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]421
422 <dd>Global values with internal linkage are only directly accessible by
423 objects in the current module. In particular, linking code into a module with
424 an internal global value may cause the internal to be renamed as necessary to
425 avoid collisions. Because the symbol is internal to the module, all
426 references can be updated. This corresponds to the notion of the
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]427 '<tt>static</tt>' keyword in C.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]428 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]429
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]430 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]431
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]432 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
433 the same name when linkage occurs. This is typically used to implement
434 inline functions, templates, or other code which must be generated in each
435 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
436 allowed to be discarded.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]437 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]438
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]439 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]440
441 <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage,
442 except that unreferenced <tt>weak</tt> globals may not be discarded. This is
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]443 used for globals that may be emitted in multiple translation units, but that
444 are not guaranteed to be emitted into every translation unit that uses them.
445 One example of this are common globals in C, such as "<tt>int X;</tt>" at
446 global scope.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]447 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]448
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]449 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]450
451 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
452 pointer to array type. When two global variables with appending linkage are
453 linked together, the two global arrays are appended together. This is the
454 LLVM, typesafe, equivalent of having the system linker append together
455 "sections" with identical names when .o files are linked.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]456 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]457
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]458 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
459 <dd>The semantics of this linkage follow the ELF model: the symbol is weak
460 until linked, if not linked, the symbol becomes null instead of being an
461 undefined reference.
462 </dd>
463</dl>
464
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]465 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]466
467 <dd>If none of the above identifiers are used, the global is externally
468 visible, meaning that it participates in linkage and can be used to resolve
469 external symbol references.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]470 </dd>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]471
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]472 <p>
473 The next two types of linkage are targeted for Microsoft Windows platform
474 only. They are designed to support importing (exporting) symbols from (to)
475 DLLs.
476 </p>
477
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]478 <dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]479 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
480
481 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
482 or variable via a global pointer to a pointer that is set up by the DLL
483 exporting the symbol. On Microsoft Windows targets, the pointer name is
484 formed by combining <code>_imp__</code> and the function or variable name.
485 </dd>
486
487 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
488
489 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
490 pointer to a pointer in a DLL, so that it can be referenced with the
491 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
492 name is formed by combining <code>_imp__</code> and the function or variable
493 name.
494 </dd>
495
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]496</dl>
497
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]498<p><a name="linkage_external"></a>For example, since the "<tt>.LC0</tt>"
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]499variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
500variable and was linked with this one, one of the two would be renamed,
501preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
502external (i.e., lacking any linkage declarations), they are accessible
Reid Spencerac8d2762007-01-05 00:59:10 +0000[diff] [blame]503outside of the current module.</p>
504<p>It is illegal for a function <i>declaration</i>
505to have any linkage type other than "externally visible", <tt>dllimport</tt>,
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]506or <tt>extern_weak</tt>.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]507
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]508</div>
509
510<!-- ======================================================================= -->
511<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]512 <a name="callingconv">Calling Conventions</a>
513</div>
514
515<div class="doc_text">
516
517<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
518and <a href="#i_invoke">invokes</a> can all have an optional calling convention
519specified for the call. The calling convention of any pair of dynamic
520caller/callee must match, or the behavior of the program is undefined. The
521following calling conventions are supported by LLVM, and more may be added in
522the future:</p>
523
524<dl>
525 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
526
527 <dd>This calling convention (the default if no other calling convention is
528 specified) matches the target C calling conventions. This calling convention
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]529 supports varargs function calls and tolerates some mismatch in the declared
Reid Spencerc28d2bc2006-12-31 21:30:18 +0000[diff] [blame]530 prototype and implemented declaration of the function (as does normal C).
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]531 </dd>
532
Chris Lattner5710ce92006-05-19 21:15:36 +0000[diff] [blame]533 <dt><b>"<tt>csretcc</tt>" - The C struct return calling convention</b>:</dt>
534
535 <dd>This calling convention matches the target C calling conventions, except
536 that functions with this convention are required to take a pointer as their
537 first argument, and the return type of the function must be void. This is
538 used for C functions that return aggregates by-value. In this case, the
539 function has been transformed to take a pointer to the struct as the first
540 argument to the function. For targets where the ABI specifies specific
541 behavior for structure-return calls, the calling convention can be used to
542 distinguish between struct return functions and other functions that take a
543 pointer to a struct as the first argument.
544 </dd>
545
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]546 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
547
548 <dd>This calling convention attempts to make calls as fast as possible
549 (e.g. by passing things in registers). This calling convention allows the
550 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner8cdc5bc2005-05-06 23:08:23 +0000[diff] [blame]551 without having to conform to an externally specified ABI. Implementations of
552 this convention should allow arbitrary tail call optimization to be supported.
553 This calling convention does not support varargs and requires the prototype of
554 all callees to exactly match the prototype of the function definition.
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]555 </dd>
556
557 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
558
559 <dd>This calling convention attempts to make code in the caller as efficient
560 as possible under the assumption that the call is not commonly executed. As
561 such, these calls often preserve all registers so that the call does not break
562 any live ranges in the caller side. This calling convention does not support
563 varargs and requires the prototype of all callees to exactly match the
564 prototype of the function definition.
565 </dd>
566
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]567 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]568
569 <dd>Any calling convention may be specified by number, allowing
570 target-specific calling conventions to be used. Target specific calling
571 conventions start at 64.
572 </dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]573</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]574
575<p>More calling conventions can be added/defined on an as-needed basis, to
576support pascal conventions or any other well-known target-independent
577convention.</p>
578
579</div>
580
581<!-- ======================================================================= -->
582<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]583 <a name="globalvars">Global Variables</a>
584</div>
585
586<div class="doc_text">
587
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]588<p>Global variables define regions of memory allocated at compilation time
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]589instead of run-time. Global variables may optionally be initialized, may have
590an explicit section to be placed in, and may
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]591have an optional explicit alignment specified. A
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]592variable may be defined as a global "constant," which indicates that the
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]593contents of the variable will <b>never</b> be modified (enabling better
594optimization, allowing the global data to be placed in the read-only section of
595an executable, etc). Note that variables that need runtime initialization
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]596cannot be marked "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]597
598<p>
599LLVM explicitly allows <em>declarations</em> of global variables to be marked
600constant, even if the final definition of the global is not. This capability
601can be used to enable slightly better optimization of the program, but requires
602the language definition to guarantee that optimizations based on the
603'constantness' are valid for the translation units that do not include the
604definition.
605</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]606
607<p>As SSA values, global variables define pointer values that are in
608scope (i.e. they dominate) all basic blocks in the program. Global
609variables always define a pointer to their "content" type because they
610describe a region of memory, and all memory objects in LLVM are
611accessed through pointers.</p>
612
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]613<p>LLVM allows an explicit section to be specified for globals. If the target
614supports it, it will emit globals to the section specified.</p>
615
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]616<p>An explicit alignment may be specified for a global. If not present, or if
617the alignment is set to zero, the alignment of the global is set by the target
618to whatever it feels convenient. If an explicit alignment is specified, the
619global is forced to have at least that much alignment. All alignments must be
620a power of 2.</p>
621
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]622<p>For example, the following defines a global with an initializer, section,
623 and alignment:</p>
624
625<pre>
626 %G = constant float 1.0, section "foo", align 4
627</pre>
628
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]629</div>
630
631
632<!-- ======================================================================= -->
633<div class="doc_subsection">
634 <a name="functionstructure">Functions</a>
635</div>
636
637<div class="doc_text">
638
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]639<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
640an optional <a href="#linkage">linkage type</a>, an optional
641<a href="#callingconv">calling convention</a>, a return type, an optional
642<a href="#paramattrs">parameter attribute</a> for the return type, a function
643name, a (possibly empty) argument list (each with optional
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]644<a href="#paramattrs">parameter attributes</a>), an optional section, an
645optional alignment, an opening curly brace, a list of basic blocks, and a
646closing curly brace. LLVM function declarations
647consist of the "<tt>declare</tt>" keyword, an optional <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]648 href="#callingconv">calling convention</a>, a return type, an optional
649<a href="#paramattrs">parameter attribute</a> for the return type, a function
650name, a possibly empty list of arguments, and an optional alignment.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]651
652<p>A function definition contains a list of basic blocks, forming the CFG for
653the function. Each basic block may optionally start with a label (giving the
654basic block a symbol table entry), contains a list of instructions, and ends
655with a <a href="#terminators">terminator</a> instruction (such as a branch or
656function return).</p>
657
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]658<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]659executed on entrance to the function, and it is not allowed to have predecessor
660basic blocks (i.e. there can not be any branches to the entry block of a
661function). Because the block can have no predecessors, it also cannot have any
662<a href="#i_phi">PHI nodes</a>.</p>
663
664<p>LLVM functions are identified by their name and type signature. Hence, two
665functions with the same name but different parameter lists or return values are
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]666considered different functions, and LLVM will resolve references to each
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]667appropriately.</p>
668
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]669<p>LLVM allows an explicit section to be specified for functions. If the target
670supports it, it will emit functions to the section specified.</p>
671
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]672<p>An explicit alignment may be specified for a function. If not present, or if
673the alignment is set to zero, the alignment of the function is set by the target
674to whatever it feels convenient. If an explicit alignment is specified, the
675function is forced to have at least that much alignment. All alignments must be
676a power of 2.</p>
677
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]678</div>
679
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]680<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]681<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
682<div class="doc_text">
683 <p>The return type and each parameter of a function type may have a set of
684 <i>parameter attributes</i> associated with them. Parameter attributes are
685 used to communicate additional information about the result or parameters of
686 a function. Parameter attributes are considered to be part of the function
687 type so two functions types that differ only by the parameter attributes
688 are different function types.</p>
689
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]690 <p>Parameter attributes consist of an at sign (@) followed by either a single
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]691 keyword or a comma separate list of keywords enclosed in parentheses. For
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]692 example:</p><pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]693 %someFunc = i16 @zext (i8 @(sext) %someParam)
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]694 %someFunc = i16 @zext (i8 @zext %someParam)</pre>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]695 <p>Note that the two function types above are unique because the parameter has
696 a different attribute (@sext in the first one, @zext in the second).</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]697
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]698 <p>Currently, only the following parameter attributes are defined:</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]699 <dl>
700 <dt><tt>@zext</tt></dt>
701 <dd>This indicates that the parameter should be zero extended just before
702 a call to this function.</dd>
703 <dt><tt>@sext</tt></dt>
704 <dd>This indicates that the parameter should be sign extended just before
705 a call to this function.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]706 </dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]707
708 <p>The current motivation for parameter attributes is to enable the sign and
709 zero extend information necessary for the C calling convention to be passed
710 from the front end to LLVM. The <tt>@zext</tt> and <tt>@sext</tt> attributes
711 are used by the code generator to perform the required extension. However,
712 parameter attributes are an orthogonal feature to calling conventions and
713 may be used for other purposes in the future.</p>
714</div>
715
716<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]717<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]718 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]719</div>
720
721<div class="doc_text">
722<p>
723Modules may contain "module-level inline asm" blocks, which corresponds to the
724GCC "file scope inline asm" blocks. These blocks are internally concatenated by
725LLVM and treated as a single unit, but may be separated in the .ll file if
726desired. The syntax is very simple:
727</p>
728
729<div class="doc_code"><pre>
Chris Lattner52599e12006-01-24 00:37:20 +0000[diff] [blame]730 module asm "inline asm code goes here"
731 module asm "more can go here"
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]732</pre></div>
733
734<p>The strings can contain any character by escaping non-printable characters.
735 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
736 for the number.
737</p>
738
739<p>
740 The inline asm code is simply printed to the machine code .s file when
741 assembly code is generated.
742</p>
743</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]744
745
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]746<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]747<div class="doc_section"> <a name="typesystem">Type System</a> </div>
748<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]749
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]750<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]751
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]752<p>The LLVM type system is one of the most important features of the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]753intermediate representation. Being typed enables a number of
754optimizations to be performed on the IR directly, without having to do
755extra analyses on the side before the transformation. A strong type
756system makes it easier to read the generated code and enables novel
757analyses and transformations that are not feasible to perform on normal
758three address code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]759
760</div>
761
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]762<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]763<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]764<div class="doc_text">
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]765<p>The primitive types are the fundamental building blocks of the LLVM
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]766system. The current set of primitive types is as follows:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]767
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]768<table class="layout">
769 <tr class="layout">
770 <td class="left">
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>void</tt></td><td>No value</td></tr>
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame^]775 <tr><td><tt>i8</tt></td><td>8-bit value</td></tr>
776 <tr><td><tt>i32</tt></td><td>32-bit value</td></tr>
Misha Brukmancfa87bc2005-04-22 18:02:52 +0000[diff] [blame]777 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]778 <tr><td><tt>label</tt></td><td>Branch destination</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]779 </tbody>
780 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]781 </td>
782 <td class="right">
783 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]784 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]785 <tr><th>Type</th><th>Description</th></tr>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]786 <tr><td><tt>i1</tt></td><td>True or False value</td></tr>
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame^]787 <tr><td><tt>i16</tt></td><td>16-bit value</td></tr>
788 <tr><td><tt>i64</tt></td><td>64-bit value</td></tr>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]789 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]790 </tbody>
791 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]792 </td>
793 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]794</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]795</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]796
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]797<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]798<div class="doc_subsubsection"> <a name="t_classifications">Type
799Classifications</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]800<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]801<p>These different primitive types fall into a few useful
802classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]803
804<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]805 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]806 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]807 <tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]808 <td><a name="t_integer">integer</a></td>
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame^]809 <td><tt>i1, i8, i16, i32, i64</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]810 </tr>
811 <tr>
812 <td><a name="t_floating">floating point</a></td>
813 <td><tt>float, double</tt></td>
814 </tr>
815 <tr>
816 <td><a name="t_firstclass">first class</a></td>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]817 <td><tt>i1, i8, i16, i32, i64, float, double, <br/>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]818 <a href="#t_pointer">pointer</a>,<a href="#t_packed">packed</a></tt>
819 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]820 </tr>
821 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]822</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]823
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]824<p>The <a href="#t_firstclass">first class</a> types are perhaps the
825most important. Values of these types are the only ones which can be
826produced by instructions, passed as arguments, or used as operands to
827instructions. This means that all structures and arrays must be
828manipulated either by pointer or by component.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]829</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]830
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]831<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]832<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]833
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]834<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]835
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]836<p>The real power in LLVM comes from the derived types in the system.
837This is what allows a programmer to represent arrays, functions,
838pointers, and other useful types. Note that these derived types may be
839recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]840
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]841</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]842
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]843<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]844<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]845
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]846<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]847
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]848<h5>Overview:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]849
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]850<p>The array type is a very simple derived type that arranges elements
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]851sequentially in memory. The array type requires a size (number of
852elements) and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]853
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]854<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]855
856<pre>
857 [&lt;# elements&gt; x &lt;elementtype&gt;]
858</pre>
859
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]860<p>The number of elements is a constant integer value; elementtype may
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]861be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]862
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]863<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]864<table class="layout">
865 <tr class="layout">
866 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]867 <tt>[40 x i32 ]</tt><br/>
868 <tt>[41 x i32 ]</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]869 <tt>[40 x i8]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]870 </td>
871 <td class="left">
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]872 Array of 40 32-bit integer values.<br/>
873 Array of 41 32-bit integer values.<br/>
874 Array of 40 8-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]875 </td>
876 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]877</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]878<p>Here are some examples of multidimensional arrays:</p>
879<table class="layout">
880 <tr class="layout">
881 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]882 <tt>[3 x [4 x i32]]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]883 <tt>[12 x [10 x float]]</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]884 <tt>[2 x [3 x [4 x i16]]]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]885 </td>
886 <td class="left">
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]887 3x4 array of 32-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]888 12x10 array of single precision floating point values.<br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]889 2x3x4 array of 16-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]890 </td>
891 </tr>
892</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]893
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]894<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
895length array. Normally, accesses past the end of an array are undefined in
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]896LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
897As a special case, however, zero length arrays are recognized to be variable
898length. This allows implementation of 'pascal style arrays' with the LLVM
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]899type "{ i32, [0 x float]}", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]900
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]901</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]902
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]903<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]904<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]905<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]906<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]907<p>The function type can be thought of as a function signature. It
908consists of a return type and a list of formal parameter types.
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]909Function types are usually used to build virtual function tables
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]910(which are structures of pointers to functions), for indirect function
911calls, and when defining a function.</p>
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]912<p>
913The return type of a function type cannot be an aggregate type.
914</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]915<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]916<pre> &lt;returntype&gt; (&lt;parameter list&gt;)<br></pre>
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]917<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]918specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]919which indicates that the function takes a variable number of arguments.
920Variable argument functions can access their arguments with the <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]921 href="#int_varargs">variable argument handling intrinsic</a> functions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]922<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]923<table class="layout">
924 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]925 <td class="left"><tt>i32 (i32)</tt></td>
926 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]927 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]928 </tr><tr class="layout">
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]929 <td class="left"><tt>float&nbsp;(i16&nbsp;@sext,&nbsp;i32&nbsp;*)&nbsp;*
930 </tt></td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]931 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
932 an <tt>i16</tt> that should be sign extended and a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]933 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]934 <tt>float</tt>.
935 </td>
936 </tr><tr class="layout">
937 <td class="left"><tt>i32 (i8*, ...)</tt></td>
938 <td class="left">A vararg function that takes at least one
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]939 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]940 which returns an integer. This is the signature for <tt>printf</tt> in
941 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]942 </td>
943 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]944</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]945
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]946</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]947<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]948<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]949<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]950<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]951<p>The structure type is used to represent a collection of data members
952together in memory. The packing of the field types is defined to match
953the ABI of the underlying processor. The elements of a structure may
954be any type that has a size.</p>
955<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
956and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
957field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
958instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]959<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]960<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]961<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]962<table class="layout">
963 <tr class="layout">
964 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]965 <tt>{ i32, i32, i32 }</tt><br/>
966 <tt>{ float, i32 (i32) * }</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]967 </td>
968 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]969 a triple of three <tt>i32</tt> values<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]970 A pair, where the first element is a <tt>float</tt> and the second element
971 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]972 that takes an <tt>i32</tt>, returning an <tt>i32</tt>.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]973 </td>
974 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]975</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]976</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]977
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]978<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]979<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
980</div>
981<div class="doc_text">
982<h5>Overview:</h5>
983<p>The packed structure type is used to represent a collection of data members
984together in memory. There is no padding between fields. Further, the alignment
985of a packed structure is 1 byte. The elements of a packed structure may
986be any type that has a size.</p>
987<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
988and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
989field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
990instruction.</p>
991<h5>Syntax:</h5>
992<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
993<h5>Examples:</h5>
994<table class="layout">
995 <tr class="layout">
996 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]997 <tt> &lt; { i32, i32, i32 } &gt; </tt><br/>
998 <tt> &lt; { float, i32 (i32) * } &gt; </tt><br/>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]999 </td>
1000 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1001 a triple of three <tt>i32</tt> values<br/>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1002 A pair, where the first element is a <tt>float</tt> and the second element
1003 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]1004 that takes an <tt>i32</tt>, returning an <tt>i32</tt>.<br/>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1005 </td>
1006 </tr>
1007</table>
1008</div>
1009
1010<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1011<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1012<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1013<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1014<p>As in many languages, the pointer type represents a pointer or
1015reference to another object, which must live in memory.</p>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1016<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1017<pre> &lt;type&gt; *<br></pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1018<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1019<table class="layout">
1020 <tr class="layout">
1021 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1022 <tt>[4x i32]*</tt><br/>
1023 <tt>i32 (i32 *) *</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1024 </td>
1025 <td class="left">
1026 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]1027 four <tt>i32</tt> values<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1028 A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1029 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
1030 <tt>i32</tt>.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1031 </td>
1032 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1033</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1034</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1035
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1036<!-- _______________________________________________________________________ -->
1037<div class="doc_subsubsection"> <a name="t_packed">Packed Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1038<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1039
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1040<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1041
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1042<p>A packed type is a simple derived type that represents a vector
1043of elements. Packed types are used when multiple primitive data
1044are operated in parallel using a single instruction (SIMD).
1045A packed type requires a size (number of
Chris Lattnerb8d172f2005-11-10 01:44:22 +0000[diff] [blame]1046elements) and an underlying primitive data type. Vectors must have a power
1047of two length (1, 2, 4, 8, 16 ...). Packed types are
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1048considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1049
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1050<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1051
1052<pre>
1053 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1054</pre>
1055
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1056<p>The number of elements is a constant integer value; elementtype may
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame^]1057be any integer or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1058
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1059<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1060
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1061<table class="layout">
1062 <tr class="layout">
1063 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1064 <tt>&lt;4 x i32&gt;</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1065 <tt>&lt;8 x float&gt;</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1066 <tt>&lt;2 x i64&gt;</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1067 </td>
1068 <td class="left">
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1069 Packed vector of 4 32-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1070 Packed vector of 8 floating-point values.<br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1071 Packed vector of 2 64-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1072 </td>
1073 </tr>
1074</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1075</div>
1076
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1077<!-- _______________________________________________________________________ -->
1078<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1079<div class="doc_text">
1080
1081<h5>Overview:</h5>
1082
1083<p>Opaque types are used to represent unknown types in the system. This
1084corresponds (for example) to the C notion of a foward declared structure type.
1085In LLVM, opaque types can eventually be resolved to any type (not just a
1086structure type).</p>
1087
1088<h5>Syntax:</h5>
1089
1090<pre>
1091 opaque
1092</pre>
1093
1094<h5>Examples:</h5>
1095
1096<table class="layout">
1097 <tr class="layout">
1098 <td class="left">
1099 <tt>opaque</tt>
1100 </td>
1101 <td class="left">
1102 An opaque type.<br/>
1103 </td>
1104 </tr>
1105</table>
1106</div>
1107
1108
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1109<!-- *********************************************************************** -->
1110<div class="doc_section"> <a name="constants">Constants</a> </div>
1111<!-- *********************************************************************** -->
1112
1113<div class="doc_text">
1114
1115<p>LLVM has several different basic types of constants. This section describes
1116them all and their syntax.</p>
1117
1118</div>
1119
1120<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1121<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1122
1123<div class="doc_text">
1124
1125<dl>
1126 <dt><b>Boolean constants</b></dt>
1127
1128 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1129 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1130 </dd>
1131
1132 <dt><b>Integer constants</b></dt>
1133
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1134 <dd>Standard integers (such as '4') are constants of the <a
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1135 href="#t_integer">integer</a> type. Negative numbers may be used with
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1136 integer types.
1137 </dd>
1138
1139 <dt><b>Floating point constants</b></dt>
1140
1141 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1142 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1143 notation (see below). Floating point constants must have a <a
1144 href="#t_floating">floating point</a> type. </dd>
1145
1146 <dt><b>Null pointer constants</b></dt>
1147
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1148 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1149 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1150
1151</dl>
1152
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1153<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1154of floating point constants. For example, the form '<tt>double
11550x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
11564.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1157(and the only time that they are generated by the disassembler) is when a
1158floating point constant must be emitted but it cannot be represented as a
1159decimal floating point number. For example, NaN's, infinities, and other
1160special values are represented in their IEEE hexadecimal format so that
1161assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1162
1163</div>
1164
1165<!-- ======================================================================= -->
1166<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1167</div>
1168
1169<div class="doc_text">
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1170<p>Aggregate constants arise from aggregation of simple constants
1171and smaller aggregate constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1172
1173<dl>
1174 <dt><b>Structure constants</b></dt>
1175
1176 <dd>Structure constants are represented with notation similar to structure
1177 type definitions (a comma separated list of elements, surrounded by braces
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1178 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* %G }</tt>",
1179 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]1180 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1181 types of elements must match those specified by the type.
1182 </dd>
1183
1184 <dt><b>Array constants</b></dt>
1185
1186 <dd>Array constants are represented with notation similar to array type
1187 definitions (a comma separated list of elements, surrounded by square brackets
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1188 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1189 constants must have <a href="#t_array">array type</a>, and the number and
1190 types of elements must match those specified by the type.
1191 </dd>
1192
1193 <dt><b>Packed constants</b></dt>
1194
1195 <dd>Packed constants are represented with notation similar to packed type
1196 definitions (a comma separated list of elements, surrounded by
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1197 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32 42,
1198 i32 11, i32 74, i32 100 &gt;</tt>". Packed constants must have <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1199 href="#t_packed">packed type</a>, and the number and types of elements must
1200 match those specified by the type.
1201 </dd>
1202
1203 <dt><b>Zero initialization</b></dt>
1204
1205 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1206 value to zero of <em>any</em> type, including scalar and aggregate types.
1207 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]1208 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1209 initializers.
1210 </dd>
1211</dl>
1212
1213</div>
1214
1215<!-- ======================================================================= -->
1216<div class="doc_subsection">
1217 <a name="globalconstants">Global Variable and Function Addresses</a>
1218</div>
1219
1220<div class="doc_text">
1221
1222<p>The addresses of <a href="#globalvars">global variables</a> and <a
1223href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1224constants. These constants are explicitly referenced when the <a
1225href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1226href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1227file:</p>
1228
1229<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1230 %X = global i32 17
1231 %Y = global i32 42
1232 %Z = global [2 x i32*] [ i32* %X, i32* %Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1233</pre>
1234
1235</div>
1236
1237<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1238<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1239<div class="doc_text">
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1240 <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]1241 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1242 a constant is permitted.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1243
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1244 <p>Undefined values indicate to the compiler that the program is well defined
1245 no matter what value is used, giving the compiler more freedom to optimize.
1246 </p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1247</div>
1248
1249<!-- ======================================================================= -->
1250<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1251</div>
1252
1253<div class="doc_text">
1254
1255<p>Constant expressions are used to allow expressions involving other constants
1256to be used as constants. Constant expressions may be of any <a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1257href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1258that does not have side effects (e.g. load and call are not supported). The
1259following is the syntax for constant expressions:</p>
1260
1261<dl>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1262 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1263 <dd>Truncate a constant to another type. The bit size of CST must be larger
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame^]1264 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1265
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1266 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1267 <dd>Zero extend a constant to another type. The bit size of CST must be
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame^]1268 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1269
1270 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1271 <dd>Sign extend a constant to another type. The bit size of CST must be
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame^]1272 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1273
1274 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1275 <dd>Truncate a floating point constant to another floating point type. The
1276 size of CST must be larger than the size of TYPE. Both types must be
1277 floating point.</dd>
1278
1279 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1280 <dd>Floating point extend a constant to another type. The size of CST must be
1281 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1282
1283 <dt><b><tt>fp2uint ( CST to TYPE )</tt></b></dt>
1284 <dd>Convert a floating point constant to the corresponding unsigned integer
1285 constant. TYPE must be an integer type. CST must be floating point. If the
1286 value won't fit in the integer type, the results are undefined.</dd>
1287
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1288 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1289 <dd>Convert a floating point constant to the corresponding signed integer
1290 constant. TYPE must be an integer type. CST must be floating point. If the
1291 value won't fit in the integer type, the results are undefined.</dd>
1292
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1293 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1294 <dd>Convert an unsigned integer constant to the corresponding floating point
1295 constant. TYPE must be floating point. CST must be of integer type. If the
1296 value won't fit in the floating point type, the results are undefined.</dd>
1297
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1298 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1299 <dd>Convert a signed integer constant to the corresponding floating point
1300 constant. TYPE must be floating point. CST must be of integer type. If the
1301 value won't fit in the floating point type, the results are undefined.</dd>
1302
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]1303 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1304 <dd>Convert a pointer typed constant to the corresponding integer constant
1305 TYPE must be an integer type. CST must be of pointer type. The CST value is
1306 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1307
1308 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1309 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1310 pointer type. CST must be of integer type. The CST value is zero extended,
1311 truncated, or unchanged to make it fit in a pointer size. This one is
1312 <i>really</i> dangerous!</dd>
1313
1314 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1315 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1316 identical (same number of bits). The conversion is done as if the CST value
1317 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]1318 with this operator, just the type. This can be used for conversion of
1319 packed types to any other type, as long as they have the same bit width. For
1320 pointers it is only valid to cast to another pointer type.
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1321 </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1322
1323 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1324
1325 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1326 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1327 instruction, the index list may have zero or more indexes, which are required
1328 to make sense for the type of "CSTPTR".</dd>
1329
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1330 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1331
1332 <dd>Perform the <a href="#i_select">select operation</a> on
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1333 constants.</dd>
1334
1335 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1336 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1337
1338 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1339 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1340
1341 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1342
1343 <dd>Perform the <a href="#i_extractelement">extractelement
1344 operation</a> on constants.
1345
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1346 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1347
1348 <dd>Perform the <a href="#i_insertelement">insertelement
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1349 operation</a> on constants.</dd>
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1350
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1351
1352 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1353
1354 <dd>Perform the <a href="#i_shufflevector">shufflevector
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1355 operation</a> on constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1356
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1357 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1358
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1359 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1360 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1361 binary</a> operations. The constraints on operands are the same as those for
1362 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1363 values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1364</dl>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1365</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]1366
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1367<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1368<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1369<!-- *********************************************************************** -->
1370
1371<!-- ======================================================================= -->
1372<div class="doc_subsection">
1373<a name="inlineasm">Inline Assembler Expressions</a>
1374</div>
1375
1376<div class="doc_text">
1377
1378<p>
1379LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1380Module-Level Inline Assembly</a>) through the use of a special value. This
1381value represents the inline assembler as a string (containing the instructions
1382to emit), a list of operand constraints (stored as a string), and a flag that
1383indicates whether or not the inline asm expression has side effects. An example
1384inline assembler expression is:
1385</p>
1386
1387<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1388 i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1389</pre>
1390
1391<p>
1392Inline assembler expressions may <b>only</b> be used as the callee operand of
1393a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1394</p>
1395
1396<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1397 %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]1398</pre>
1399
1400<p>
1401Inline asms with side effects not visible in the constraint list must be marked
1402as having side effects. This is done through the use of the
1403'<tt>sideeffect</tt>' keyword, like so:
1404</p>
1405
1406<pre>
1407 call void asm sideeffect "eieio", ""()
1408</pre>
1409
1410<p>TODO: The format of the asm and constraints string still need to be
1411documented here. Constraints on what can be done (e.g. duplication, moving, etc
1412need to be documented).
1413</p>
1414
1415</div>
1416
1417<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1418<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1419<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1420
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1421<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1422
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1423<p>The LLVM instruction set consists of several different
1424classifications of instructions: <a href="#terminators">terminator
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1425instructions</a>, <a href="#binaryops">binary instructions</a>,
1426<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1427 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1428instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1429
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1430</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1431
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1432<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1433<div class="doc_subsection"> <a name="terminators">Terminator
1434Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1435
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1436<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1437
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1438<p>As mentioned <a href="#functionstructure">previously</a>, every
1439basic block in a program ends with a "Terminator" instruction, which
1440indicates which block should be executed after the current block is
1441finished. These terminator instructions typically yield a '<tt>void</tt>'
1442value: they produce control flow, not values (the one exception being
1443the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1444<p>There are six different terminator instructions: the '<a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1445 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1446instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1447the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1448 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1449 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1450
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1451</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1452
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1453<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1454<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1455Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1456<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1457<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1458<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]1459 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1460</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1461<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1462<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1463value) from a function back to the caller.</p>
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]1464<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1465returns a value and then causes control flow, and one that just causes
1466control flow to occur.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1467<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1468<p>The '<tt>ret</tt>' instruction may return any '<a
1469 href="#t_firstclass">first class</a>' type. Notice that a function is
1470not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
1471instruction inside of the function that returns a value that does not
1472match the return type of the function.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1473<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1474<p>When the '<tt>ret</tt>' instruction is executed, control flow
1475returns back to the calling function's context. If the caller is a "<a
John Criswellfa081872004-06-25 15:16:57 +0000[diff] [blame]1476 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1477the instruction after the call. If the caller was an "<a
1478 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1479at the beginning of the "normal" destination block. If the instruction
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1480returns a value, that value shall set the call or invoke instruction's
1481return value.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1482<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1483<pre> ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1484 ret void <i>; Return from a void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1485</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1486</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1487<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1488<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1489<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1490<h5>Syntax:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1491<pre> br i1 &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]1492</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1493<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1494<p>The '<tt>br</tt>' instruction is used to cause control flow to
1495transfer to a different basic block in the current function. There are
1496two forms of this instruction, corresponding to a conditional branch
1497and an unconditional branch.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1498<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1499<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1500single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1501unconditional form of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>'
1502value as a target.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1503<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1504<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1505argument is evaluated. If the value is <tt>true</tt>, control flows
1506to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1507control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1508<h5>Example:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1509<pre>Test:<br> %cond = <a href="#i_icmp">icmp</a> eq, i32 %a, %b<br> br i1 %cond, label %IfEqual, label %IfUnequal<br>IfEqual:<br> <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1510 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]1511</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1512<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1513<div class="doc_subsubsection">
1514 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1515</div>
1516
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1517<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1518<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1519
1520<pre>
1521 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1522</pre>
1523
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1524<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1525
1526<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1527several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1528instruction, allowing a branch to occur to one of many possible
1529destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1530
1531
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1532<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1533
1534<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1535comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1536an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1537table is not allowed to contain duplicate constant entries.</p>
1538
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1539<h5>Semantics:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1540
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1541<p>The <tt>switch</tt> instruction specifies a table of values and
1542destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1543table is searched for the given value. If the value is found, control flow is
1544transfered to the corresponding destination; otherwise, control flow is
1545transfered to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1546
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1547<h5>Implementation:</h5>
1548
1549<p>Depending on properties of the target machine and the particular
1550<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1551ways. For example, it could be generated as a series of chained conditional
1552branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1553
1554<h5>Example:</h5>
1555
1556<pre>
1557 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1558 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1559 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1560
1561 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1562 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1563
1564 <i>; Implement a jump table:</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1565 switch i32 %val, label %otherwise [ i32 0, label %onzero
1566 i32 1, label %onone
1567 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1568</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1569</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1570
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1571<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1572<div class="doc_subsubsection">
1573 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1574</div>
1575
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1576<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1577
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1578<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1579
1580<pre>
1581 &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]1582 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1583</pre>
1584
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1585<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1586
1587<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1588function, with the possibility of control flow transfer to either the
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1589'<tt>normal</tt>' label or the
1590'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1591"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1592"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1593href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
1594continued at the dynamically nearest "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1595
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1596<h5>Arguments:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1597
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1598<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1599
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1600<ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1601 <li>
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1602 The optional "cconv" marker indicates which <a href="callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1603 convention</a> the call should use. If none is specified, the call defaults
1604 to using C calling conventions.
1605 </li>
1606 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1607 function value being invoked. In most cases, this is a direct function
1608 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1609 an arbitrary pointer to function value.
1610 </li>
1611
1612 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1613 function to be invoked. </li>
1614
1615 <li>'<tt>function args</tt>': argument list whose types match the function
1616 signature argument types. If the function signature indicates the function
1617 accepts a variable number of arguments, the extra arguments can be
1618 specified. </li>
1619
1620 <li>'<tt>normal label</tt>': the label reached when the called function
1621 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1622
1623 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1624 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1625
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1626</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1627
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1628<h5>Semantics:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1629
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1630<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1631href="#i_call">call</a></tt>' instruction in most regards. The primary
1632difference is that it establishes an association with a label, which is used by
1633the runtime library to unwind the stack.</p>
1634
1635<p>This instruction is used in languages with destructors to ensure that proper
1636cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1637exception. Additionally, this is important for implementation of
1638'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1639
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1640<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1641<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1642 %retval = invoke i32 %Test(i32 15) to label %Continue
1643 unwind label %TestCleanup <i>; {i32}:retval set</i>
1644 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Test(i32 15) to label %Continue
1645 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1646</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1647</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1648
1649
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1650<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1651
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1652<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1653Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1654
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1655<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1656
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1657<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1658<pre>
1659 unwind
1660</pre>
1661
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1662<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1663
1664<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
1665at the first callee in the dynamic call stack which used an <a
1666href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
1667primarily used to implement exception handling.</p>
1668
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1669<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1670
1671<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
1672immediately halt. The dynamic call stack is then searched for the first <a
1673href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
1674execution continues at the "exceptional" destination block specified by the
1675<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
1676dynamic call chain, undefined behavior results.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1677</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1678
1679<!-- _______________________________________________________________________ -->
1680
1681<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
1682Instruction</a> </div>
1683
1684<div class="doc_text">
1685
1686<h5>Syntax:</h5>
1687<pre>
1688 unreachable
1689</pre>
1690
1691<h5>Overview:</h5>
1692
1693<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
1694instruction is used to inform the optimizer that a particular portion of the
1695code is not reachable. This can be used to indicate that the code after a
1696no-return function cannot be reached, and other facts.</p>
1697
1698<h5>Semantics:</h5>
1699
1700<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
1701</div>
1702
1703
1704
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1705<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1706<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1707<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1708<p>Binary operators are used to do most of the computation in a
1709program. They require two operands, execute an operation on them, and
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1710produce a single value. The operands might represent
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1711multiple data, as is the case with the <a href="#t_packed">packed</a> data type.
1712The result value of a binary operator is not
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1713necessarily the same type as its operands.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1714<p>There are several different binary operators:</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1715</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1716<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1717<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
1718Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1719<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1720<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1721<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]1722</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1723<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1724<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1725<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1726<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1727 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
1728 This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1729Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1730<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1731<p>The value produced is the integer or floating point sum of the two
1732operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1733<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1734<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]1735</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1736</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1737<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1738<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
1739Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1740<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1741<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1742<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]1743</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1744<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1745<p>The '<tt>sub</tt>' instruction returns the difference of its two
1746operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1747<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
1748instruction present in most other intermediate representations.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1749<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1750<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1751 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1752values.
1753This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1754Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1755<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1756<p>The value produced is the integer or floating point difference of
1757the two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1758<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1759<pre> &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
1760 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1761</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1762</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1763<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1764<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
1765Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1766<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1767<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1768<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]1769</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1770<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1771<p>The '<tt>mul</tt>' instruction returns the product of its two
1772operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1773<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1774<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1775 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1776values.
1777This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1778Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1779<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1780<p>The value produced is the integer or floating point product of the
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1781two operands.</p>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1782<p>Because the operands are the same width, the result of an integer
1783multiplication is the same whether the operands should be deemed unsigned or
1784signed.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1785<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1786<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]1787</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1788</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1789<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1790<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
1791</a></div>
1792<div class="doc_text">
1793<h5>Syntax:</h5>
1794<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1795</pre>
1796<h5>Overview:</h5>
1797<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
1798operands.</p>
1799<h5>Arguments:</h5>
1800<p>The two arguments to the '<tt>udiv</tt>' instruction must be
1801<a href="#t_integer">integer</a> values. Both arguments must have identical
1802types. This instruction can also take <a href="#t_packed">packed</a> versions
1803of the values in which case the elements must be integers.</p>
1804<h5>Semantics:</h5>
1805<p>The value produced is the unsigned integer quotient of the two operands. This
1806instruction always performs an unsigned division operation, regardless of
1807whether the arguments are unsigned or not.</p>
1808<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1809<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]1810</pre>
1811</div>
1812<!-- _______________________________________________________________________ -->
1813<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
1814</a> </div>
1815<div class="doc_text">
1816<h5>Syntax:</h5>
1817<pre> &lt;result&gt; = sdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1818</pre>
1819<h5>Overview:</h5>
1820<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
1821operands.</p>
1822<h5>Arguments:</h5>
1823<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
1824<a href="#t_integer">integer</a> values. Both arguments must have identical
1825types. This instruction can also take <a href="#t_packed">packed</a> versions
1826of the values in which case the elements must be integers.</p>
1827<h5>Semantics:</h5>
1828<p>The value produced is the signed integer quotient of the two operands. This
1829instruction always performs a signed division operation, regardless of whether
1830the arguments are signed or not.</p>
1831<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1832<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]1833</pre>
1834</div>
1835<!-- _______________________________________________________________________ -->
1836<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1837Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1838<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1839<h5>Syntax:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1840<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]1841</pre>
1842<h5>Overview:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1843<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1844operands.</p>
1845<h5>Arguments:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1846<p>The two arguments to the '<tt>div</tt>' instruction must be
1847<a href="#t_floating">floating point</a> values. Both arguments must have
1848identical types. This instruction can also take <a href="#t_packed">packed</a>
1849versions of the values in which case the elements must be floating point.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1850<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1851<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1852<h5>Example:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1853<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]1854</pre>
1855</div>
1856<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1857<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
1858</div>
1859<div class="doc_text">
1860<h5>Syntax:</h5>
1861<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1862</pre>
1863<h5>Overview:</h5>
1864<p>The '<tt>urem</tt>' instruction returns the remainder from the
1865unsigned division of its two arguments.</p>
1866<h5>Arguments:</h5>
1867<p>The two arguments to the '<tt>urem</tt>' instruction must be
1868<a href="#t_integer">integer</a> values. Both arguments must have identical
1869types.</p>
1870<h5>Semantics:</h5>
1871<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
1872This instruction always performs an unsigned division to get the remainder,
1873regardless of whether the arguments are unsigned or not.</p>
1874<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1875<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]1876</pre>
1877
1878</div>
1879<!-- _______________________________________________________________________ -->
1880<div class="doc_subsubsection"> <a name="i_srem">'<tt>srem</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1881Instruction</a> </div>
1882<div class="doc_text">
1883<h5>Syntax:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1884<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]1885</pre>
1886<h5>Overview:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1887<p>The '<tt>srem</tt>' instruction returns the remainder from the
1888signed division of its two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1889<h5>Arguments:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1890<p>The two arguments to the '<tt>srem</tt>' instruction must be
1891<a href="#t_integer">integer</a> values. Both arguments must have identical
1892types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1893<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1894<p>This instruction returns the <i>remainder</i> of a division (where the result
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1895has the same sign as the divisor), not the <i>modulus</i> (where the
1896result has the same sign as the dividend) of a value. For more
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1897information about the difference, see <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1898 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
1899Math Forum</a>.</p>
1900<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1901<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]1902</pre>
1903
1904</div>
1905<!-- _______________________________________________________________________ -->
1906<div class="doc_subsubsection"> <a name="i_frem">'<tt>frem</tt>'
1907Instruction</a> </div>
1908<div class="doc_text">
1909<h5>Syntax:</h5>
1910<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1911</pre>
1912<h5>Overview:</h5>
1913<p>The '<tt>frem</tt>' instruction returns the remainder from the
1914division of its two operands.</p>
1915<h5>Arguments:</h5>
1916<p>The two arguments to the '<tt>frem</tt>' instruction must be
1917<a href="#t_floating">floating point</a> values. Both arguments must have
1918identical types.</p>
1919<h5>Semantics:</h5>
1920<p>This instruction returns the <i>remainder</i> of a division.</p>
1921<h5>Example:</h5>
1922<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]1923</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1924</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]1925
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1926<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1927<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
1928Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1929<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1930<p>Bitwise binary operators are used to do various forms of
1931bit-twiddling in a program. They are generally very efficient
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1932instructions and can commonly be strength reduced from other
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1933instructions. They require two operands, execute an operation on them,
1934and produce a single value. The resulting value of the bitwise binary
1935operators is always the same type as its first operand.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1936</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1937<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1938<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
1939Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1940<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1941<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1942<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]1943</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1944<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1945<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
1946its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1947<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1948<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame^]1949 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1950identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1951<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1952<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1953<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1954<div style="align: center">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1955<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1956 <tbody>
1957 <tr>
1958 <td>In0</td>
1959 <td>In1</td>
1960 <td>Out</td>
1961 </tr>
1962 <tr>
1963 <td>0</td>
1964 <td>0</td>
1965 <td>0</td>
1966 </tr>
1967 <tr>
1968 <td>0</td>
1969 <td>1</td>
1970 <td>0</td>
1971 </tr>
1972 <tr>
1973 <td>1</td>
1974 <td>0</td>
1975 <td>0</td>
1976 </tr>
1977 <tr>
1978 <td>1</td>
1979 <td>1</td>
1980 <td>1</td>
1981 </tr>
1982 </tbody>
1983</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1984</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1985<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1986<pre> &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
1987 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
1988 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1989</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1990</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1991<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1992<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1993<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1994<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1995<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]1996</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1997<h5>Overview:</h5>
1998<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
1999or of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2000<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2001<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame^]2002 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2003identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2004<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2005<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2006<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2007<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2008<table border="1" cellspacing="0" cellpadding="4">
2009 <tbody>
2010 <tr>
2011 <td>In0</td>
2012 <td>In1</td>
2013 <td>Out</td>
2014 </tr>
2015 <tr>
2016 <td>0</td>
2017 <td>0</td>
2018 <td>0</td>
2019 </tr>
2020 <tr>
2021 <td>0</td>
2022 <td>1</td>
2023 <td>1</td>
2024 </tr>
2025 <tr>
2026 <td>1</td>
2027 <td>0</td>
2028 <td>1</td>
2029 </tr>
2030 <tr>
2031 <td>1</td>
2032 <td>1</td>
2033 <td>1</td>
2034 </tr>
2035 </tbody>
2036</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2037</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2038<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2039<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2040 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2041 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2042</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2043</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2044<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2045<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2046Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2047<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2048<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2049<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]2050</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2051<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2052<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2053or of its two operands. The <tt>xor</tt> is used to implement the
2054"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2055<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2056<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame^]2057 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2058identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2059<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2060<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2061<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2062<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2063<table border="1" cellspacing="0" cellpadding="4">
2064 <tbody>
2065 <tr>
2066 <td>In0</td>
2067 <td>In1</td>
2068 <td>Out</td>
2069 </tr>
2070 <tr>
2071 <td>0</td>
2072 <td>0</td>
2073 <td>0</td>
2074 </tr>
2075 <tr>
2076 <td>0</td>
2077 <td>1</td>
2078 <td>1</td>
2079 </tr>
2080 <tr>
2081 <td>1</td>
2082 <td>0</td>
2083 <td>1</td>
2084 </tr>
2085 <tr>
2086 <td>1</td>
2087 <td>1</td>
2088 <td>0</td>
2089 </tr>
2090 </tbody>
2091</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2092</div>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2093<p> </p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2094<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2095<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2096 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2097 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2098 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2099</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2100</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2101<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2102<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2103Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2104<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2105<h5>Syntax:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2106<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]2107</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2108<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2109<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2110the left a specified number of bits.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2111<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2112<p>The first argument to the '<tt>shl</tt>' instruction must be an <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2113 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]2114type.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2115<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2116<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]2117<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2118<pre> &lt;result&gt; = shl i32 4, i8 %var <i>; yields {i32}:result = 4 &lt;&lt; %var</i>
2119 &lt;result&gt; = shl i32 4, i8 2 <i>; yields {i32}:result = 16</i>
2120 &lt;result&gt; = shl i32 1, i8 10 <i>; yields {i32}:result = 1024</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2121</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2122</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2123<!-- _______________________________________________________________________ -->
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2124<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2125Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2126<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2127<h5>Syntax:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2128<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]2129</pre>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2130
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2131<h5>Overview:</h5>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2132<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
2133operand shifted to the right a specified number of bits.</p>
2134
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2135<h5>Arguments:</h5>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2136<p>The first argument to the '<tt>lshr</tt>' instruction must be an <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2137 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]2138
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2139<h5>Semantics:</h5>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]2140<p>This instruction always performs a logical shift right operation. The
2141<tt>var2</tt> most significant bits will be filled with zero bits after the
2142shift.</p>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2143
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2144<h5>Example:</h5>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2145<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2146 &lt;result&gt; = lshr i32 4, i8 1 <i>; yields {i32}:result = 2</i>
2147 &lt;result&gt; = lshr i32 4, i8 2 <i>; yields {i32}:result = 1</i>
2148 &lt;result&gt; = lshr i8 4, i8 3 <i>; yields {i8 }:result = 0</i>
2149 &lt;result&gt; = lshr i8 -2, i8 1 <i>; yields {i8 }:result = 0x7FFFFFFF </i>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2150</pre>
2151</div>
2152
2153<!-- ======================================================================= -->
2154<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2155Instruction</a> </div>
2156<div class="doc_text">
2157
2158<h5>Syntax:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2159<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]2160</pre>
2161
2162<h5>Overview:</h5>
2163<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
2164operand shifted to the right a specified number of bits.</p>
2165
2166<h5>Arguments:</h5>
2167<p>The first argument to the '<tt>ashr</tt>' instruction must be an
2168<a href="#t_integer">integer</a> type. The second argument must be an
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2169'<tt>i8</tt>' type.</p>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2170
2171<h5>Semantics:</h5>
2172<p>This instruction always performs an arithmetic shift right operation,
2173regardless of whether the arguments are signed or not. The <tt>var2</tt> most
2174significant bits will be filled with the sign bit of <tt>var1</tt>.</p>
2175
2176<h5>Example:</h5>
2177<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2178 &lt;result&gt; = ashr i32 4, i8 1 <i>; yields {i32}:result = 2</i>
2179 &lt;result&gt; = ashr i32 4, i8 2 <i>; yields {i32}:result = 1</i>
2180 &lt;result&gt; = ashr i8 4, i8 3 <i>; yields {i8}:result = 0</i>
2181 &lt;result&gt; = ashr i8 -2, i8 1 <i>; yields {i8 }:result = -1</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2182</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2183</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2184
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2185<!-- ======================================================================= -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2186<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2187 <a name="vectorops">Vector Operations</a>
2188</div>
2189
2190<div class="doc_text">
2191
2192<p>LLVM supports several instructions to represent vector operations in a
2193target-independent manner. This instructions cover the element-access and
2194vector-specific operations needed to process vectors effectively. While LLVM
2195does directly support these vector operations, many sophisticated algorithms
2196will want to use target-specific intrinsics to take full advantage of a specific
2197target.</p>
2198
2199</div>
2200
2201<!-- _______________________________________________________________________ -->
2202<div class="doc_subsubsection">
2203 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2204</div>
2205
2206<div class="doc_text">
2207
2208<h5>Syntax:</h5>
2209
2210<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2211 &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]2212</pre>
2213
2214<h5>Overview:</h5>
2215
2216<p>
2217The '<tt>extractelement</tt>' instruction extracts a single scalar
2218element from a packed vector at a specified index.
2219</p>
2220
2221
2222<h5>Arguments:</h5>
2223
2224<p>
2225The first operand of an '<tt>extractelement</tt>' instruction is a
2226value of <a href="#t_packed">packed</a> type. The second operand is
2227an index indicating the position from which to extract the element.
2228The index may be a variable.</p>
2229
2230<h5>Semantics:</h5>
2231
2232<p>
2233The result is a scalar of the same type as the element type of
2234<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2235<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2236results are undefined.
2237</p>
2238
2239<h5>Example:</h5>
2240
2241<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2242 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2243</pre>
2244</div>
2245
2246
2247<!-- _______________________________________________________________________ -->
2248<div class="doc_subsubsection">
2249 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2250</div>
2251
2252<div class="doc_text">
2253
2254<h5>Syntax:</h5>
2255
2256<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2257 &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]2258</pre>
2259
2260<h5>Overview:</h5>
2261
2262<p>
2263The '<tt>insertelement</tt>' instruction inserts a scalar
2264element into a packed vector at a specified index.
2265</p>
2266
2267
2268<h5>Arguments:</h5>
2269
2270<p>
2271The first operand of an '<tt>insertelement</tt>' instruction is a
2272value of <a href="#t_packed">packed</a> type. The second operand is a
2273scalar value whose type must equal the element type of the first
2274operand. The third operand is an index indicating the position at
2275which to insert the value. The index may be a variable.</p>
2276
2277<h5>Semantics:</h5>
2278
2279<p>
2280The result is a packed vector of the same type as <tt>val</tt>. Its
2281element values are those of <tt>val</tt> except at position
2282<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2283exceeds the length of <tt>val</tt>, the results are undefined.
2284</p>
2285
2286<h5>Example:</h5>
2287
2288<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2289 %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]2290</pre>
2291</div>
2292
2293<!-- _______________________________________________________________________ -->
2294<div class="doc_subsubsection">
2295 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2296</div>
2297
2298<div class="doc_text">
2299
2300<h5>Syntax:</h5>
2301
2302<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2303 &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]2304</pre>
2305
2306<h5>Overview:</h5>
2307
2308<p>
2309The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2310from two input vectors, returning a vector of the same type.
2311</p>
2312
2313<h5>Arguments:</h5>
2314
2315<p>
2316The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2317with types that match each other and types that match the result of the
2318instruction. The third argument is a shuffle mask, which has the same number
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2319of elements as the other vector type, but whose element type is always 'i32'.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2320</p>
2321
2322<p>
2323The shuffle mask operand is required to be a constant vector with either
2324constant integer or undef values.
2325</p>
2326
2327<h5>Semantics:</h5>
2328
2329<p>
2330The elements of the two input vectors are numbered from left to right across
2331both of the vectors. The shuffle mask operand specifies, for each element of
2332the result vector, which element of the two input registers the result element
2333gets. The element selector may be undef (meaning "don't care") and the second
2334operand may be undef if performing a shuffle from only one vector.
2335</p>
2336
2337<h5>Example:</h5>
2338
2339<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2340 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
2341 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
2342 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2343 &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]2344</pre>
2345</div>
2346
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]2347
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2348<!-- ======================================================================= -->
2349<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2350 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2351</div>
2352
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2353<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2354
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2355<p>A key design point of an SSA-based representation is how it
2356represents memory. In LLVM, no memory locations are in SSA form, which
2357makes things very simple. This section describes how to read, write,
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2358allocate, and free memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2359
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2360</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2361
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2362<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2363<div class="doc_subsubsection">
2364 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2365</div>
2366
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2367<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2368
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2369<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2370
2371<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2372 &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]2373</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2374
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2375<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2376
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2377<p>The '<tt>malloc</tt>' instruction allocates memory from the system
2378heap and returns a pointer to it.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2379
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2380<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2381
2382<p>The '<tt>malloc</tt>' instruction allocates
2383<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswell6e4ca612004-02-24 16:13:56 +0000[diff] [blame]2384bytes of memory from the operating system and returns a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2385appropriate type to the program. If "NumElements" is specified, it is the
2386number of elements allocated. If an alignment is specified, the value result
2387of the allocation is guaranteed to be aligned to at least that boundary. If
2388not specified, or if zero, the target can choose to align the allocation on any
2389convenient boundary.</p>
2390
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2391<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2392
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2393<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2394
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2395<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
2396a pointer is returned.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2397
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2398<h5>Example:</h5>
2399
2400<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2401 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2402
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2403 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
2404 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
2405 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
2406 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
2407 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2408</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2409</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2410
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2411<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2412<div class="doc_subsubsection">
2413 <a name="i_free">'<tt>free</tt>' Instruction</a>
2414</div>
2415
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2416<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2417
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2418<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2419
2420<pre>
2421 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2422</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2423
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2424<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2425
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2426<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2427memory heap to be reallocated in the future.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2428
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2429<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2430
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2431<p>'<tt>value</tt>' shall be a pointer value that points to a value
2432that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
2433instruction.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2434
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2435<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2436
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2437<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2438after this instruction executes.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2439
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2440<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2441
2442<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2443 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
2444 free [4 x i8]* %array
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2445</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2446</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2447
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2448<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2449<div class="doc_subsubsection">
2450 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
2451</div>
2452
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2453<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2454
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2455<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2456
2457<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2458 &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]2459</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2460
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2461<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2462
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2463<p>The '<tt>alloca</tt>' instruction allocates memory on the current
2464stack frame of the procedure that is live until the current function
2465returns to its caller.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2466
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2467<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2468
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2469<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2470bytes of memory on the runtime stack, returning a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2471appropriate type to the program. If "NumElements" is specified, it is the
2472number of elements allocated. If an alignment is specified, the value result
2473of the allocation is guaranteed to be aligned to at least that boundary. If
2474not specified, or if zero, the target can choose to align the allocation on any
2475convenient boundary.</p>
2476
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2477<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2478
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2479<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2480
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2481<p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2482memory is automatically released when the function returns. The '<tt>alloca</tt>'
2483instruction is commonly used to represent automatic variables that must
2484have an address available. When the function returns (either with the <tt><a
John Criswelldae2e932005-05-12 16:55:34 +0000[diff] [blame]2485 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]2486instructions), the memory is reclaimed.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2487
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2488<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2489
2490<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2491 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
2492 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
2493 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
2494 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2495</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2496</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2497
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2498<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2499<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
2500Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2501<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2502<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2503<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]2504<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2505<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2506<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2507<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2508address from which to load. The pointer must point to a <a
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]2509 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2510marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2511the number or order of execution of this <tt>load</tt> with other
2512volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
2513instructions. </p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2514<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2515<p>The location of memory pointed to is loaded.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2516<h5>Examples:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2517<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2518 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2519 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2520 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2521</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2522</div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2523<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2524<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
2525Instruction</a> </div>
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]2526<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2527<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2528<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]2529 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]2530</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2531<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2532<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2533<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2534<p>There are two arguments to the '<tt>store</tt>' instruction: a value
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2535to 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]2536operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2537operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2538optimizer is not allowed to modify the number or order of execution of
2539this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
2540 href="#i_store">store</a></tt> instructions.</p>
2541<h5>Semantics:</h5>
2542<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
2543at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2544<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2545<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2546 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2547 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2548 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2549</pre>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2550</div>
2551
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2552<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2553<div class="doc_subsubsection">
2554 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
2555</div>
2556
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2557<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2558<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2559<pre>
2560 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
2561</pre>
2562
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2563<h5>Overview:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2564
2565<p>
2566The '<tt>getelementptr</tt>' instruction is used to get the address of a
2567subelement of an aggregate data structure.</p>
2568
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2569<h5>Arguments:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2570
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2571<p>This instruction takes a list of integer operands that indicate what
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2572elements of the aggregate object to index to. The actual types of the arguments
2573provided depend on the type of the first pointer argument. The
2574'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2575levels 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]2576structure, only <tt>i32</tt> integer constants are allowed. When indexing
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2577into an array or pointer, only integers of 32 or 64 bits are allowed, and will
2578be sign extended to 64-bit values.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2579
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2580<p>For example, let's consider a C code fragment and how it gets
2581compiled to LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2582
2583<pre>
2584 struct RT {
2585 char A;
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2586 i32 B[10][20];
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2587 char C;
2588 };
2589 struct ST {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2590 i32 X;
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2591 double Y;
2592 struct RT Z;
2593 };
2594
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2595 define i32 *foo(struct ST *s) {
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2596 return &amp;s[1].Z.B[5][13];
2597 }
2598</pre>
2599
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2600<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2601
2602<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2603 %RT = type { i8 , [10 x [20 x i32]], i8 }
2604 %ST = type { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2605
Brian Gaeke7283e7c2004-07-02 21:08:14 +0000[diff] [blame]2606 implementation
2607
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2608 define i32* %foo(%ST* %s) {
Brian Gaeke7283e7c2004-07-02 21:08:14 +0000[diff] [blame]2609 entry:
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2610 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
2611 ret i32* %reg
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2612 }
2613</pre>
2614
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2615<h5>Semantics:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2616
2617<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2618on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2619and <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]2620<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]2621to 64-bits. <a href="#t_struct">Structure</a> types, require <tt>i32</tt>
Reid Spencer42ddd842006-12-03 16:53:48 +0000[diff] [blame]2622<b>constants</b>.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2623
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2624<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]2625type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2626}</tt>' type, a structure. The second index indexes into the third element of
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2627the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
2628i8 }</tt>' type, another structure. The third index indexes into the second
2629element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2630array. The two dimensions of the array are subscripted into, yielding an
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2631'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
2632to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2633
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2634<p>Note that it is perfectly legal to index partially through a
2635structure, returning a pointer to an inner element. Because of this,
2636the LLVM code for the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2637
2638<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2639 define i32* %foo(%ST* %s) {
2640 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
2641 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
2642 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
2643 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
2644 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
2645 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2646 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2647</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2648
2649<p>Note that it is undefined to access an array out of bounds: array and
2650pointer indexes must always be within the defined bounds of the array type.
2651The one exception for this rules is zero length arrays. These arrays are
2652defined to be accessible as variable length arrays, which requires access
2653beyond the zero'th element.</p>
2654
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2655<p>The getelementptr instruction is often confusing. For some more insight
2656into how it works, see <a href="GetElementPtr.html">the getelementptr
2657FAQ</a>.</p>
2658
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2659<h5>Example:</h5>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2660
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2661<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2662 <i>; yields [12 x i8]*:aptr</i>
2663 %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2664</pre>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2665</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2666
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2667<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]2668<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2669</div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2670<div class="doc_text">
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]2671<p>The instructions in this category are the conversion instructions (casting)
2672which all take a single operand and a type. They perform various bit conversions
2673on the operand.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2674</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2675
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2676<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2677<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2678 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
2679</div>
2680<div class="doc_text">
2681
2682<h5>Syntax:</h5>
2683<pre>
2684 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2685</pre>
2686
2687<h5>Overview:</h5>
2688<p>
2689The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
2690</p>
2691
2692<h5>Arguments:</h5>
2693<p>
2694The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
2695be an <a href="#t_integer">integer</a> type, and a type that specifies the size
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame^]2696and type of the result, which must be an <a href="#t_integer">integer</a>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2697type. The bit size of <tt>value</tt> must be larger than the bit size of
2698<tt>ty2</tt>. Equal sized types are not allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2699
2700<h5>Semantics:</h5>
2701<p>
2702The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2703and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
2704larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
2705It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2706
2707<h5>Example:</h5>
2708<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2709 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2710 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
2711 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2712</pre>
2713</div>
2714
2715<!-- _______________________________________________________________________ -->
2716<div class="doc_subsubsection">
2717 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
2718</div>
2719<div class="doc_text">
2720
2721<h5>Syntax:</h5>
2722<pre>
2723 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2724</pre>
2725
2726<h5>Overview:</h5>
2727<p>The '<tt>zext</tt>' instruction zero extends its operand to type
2728<tt>ty2</tt>.</p>
2729
2730
2731<h5>Arguments:</h5>
2732<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame^]2733<a href="#t_integer">integer</a> type, and a type to cast it to, which must
2734also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2735<tt>value</tt> must be smaller than the bit size of the destination type,
2736<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2737
2738<h5>Semantics:</h5>
2739<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
2740bits until it reaches the size of the destination type, <tt>ty2</tt>. When the
2741the operand and the type are the same size, no bit filling is done and the
2742cast is considered a <i>no-op cast</i> because no bits change (only the type
2743changes).</p>
2744
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]2745<p>When zero extending from i1, the result will always be either 0 or 1.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2746
2747<h5>Example:</h5>
2748<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2749 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2750 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2751</pre>
2752</div>
2753
2754<!-- _______________________________________________________________________ -->
2755<div class="doc_subsubsection">
2756 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
2757</div>
2758<div class="doc_text">
2759
2760<h5>Syntax:</h5>
2761<pre>
2762 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2763</pre>
2764
2765<h5>Overview:</h5>
2766<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
2767
2768<h5>Arguments:</h5>
2769<p>
2770The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame^]2771<a href="#t_integer">integer</a> type, and a type to cast it to, which must
2772also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2773<tt>value</tt> must be smaller than the bit size of the destination type,
2774<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2775
2776<h5>Semantics:</h5>
2777<p>
2778The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
2779bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
2780the type <tt>ty2</tt>. When the the operand and the type are the same size,
2781no bit filling is done and the cast is considered a <i>no-op cast</i> because
2782no bits change (only the type changes).</p>
2783
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2784<p>When sign extending from i1, the extension always results in -1 or 0.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2785
2786<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2787<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2788 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2789 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2790</pre>
2791</div>
2792
2793<!-- _______________________________________________________________________ -->
2794<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]2795 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
2796</div>
2797
2798<div class="doc_text">
2799
2800<h5>Syntax:</h5>
2801
2802<pre>
2803 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2804</pre>
2805
2806<h5>Overview:</h5>
2807<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
2808<tt>ty2</tt>.</p>
2809
2810
2811<h5>Arguments:</h5>
2812<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
2813 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
2814cast it to. The size of <tt>value</tt> must be larger than the size of
2815<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
2816<i>no-op cast</i>.</p>
2817
2818<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2819<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
2820<a href="#t_floating">floating point</a> type to a smaller
2821<a href="#t_floating">floating point</a> type. If the value cannot fit within
2822the destination type, <tt>ty2</tt>, then the results are undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]2823
2824<h5>Example:</h5>
2825<pre>
2826 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
2827 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
2828</pre>
2829</div>
2830
2831<!-- _______________________________________________________________________ -->
2832<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2833 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
2834</div>
2835<div class="doc_text">
2836
2837<h5>Syntax:</h5>
2838<pre>
2839 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2840</pre>
2841
2842<h5>Overview:</h5>
2843<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
2844floating point value.</p>
2845
2846<h5>Arguments:</h5>
2847<p>The '<tt>fpext</tt>' instruction takes a
2848<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2849and a <a href="#t_floating">floating point</a> type to cast it to. The source
2850type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2851
2852<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2853<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
2854<a href="t_floating">floating point</a> type to a larger
2855<a href="t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
2856used to make a <i>no-op cast</i> because it always changes bits. Use
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2857<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]2858
2859<h5>Example:</h5>
2860<pre>
2861 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
2862 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
2863</pre>
2864</div>
2865
2866<!-- _______________________________________________________________________ -->
2867<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2868 <a name="i_fp2uint">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2869</div>
2870<div class="doc_text">
2871
2872<h5>Syntax:</h5>
2873<pre>
2874 &lt;result&gt; = fp2uint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2875</pre>
2876
2877<h5>Overview:</h5>
2878<p>The '<tt>fp2uint</tt>' converts a floating point <tt>value</tt> to its
2879unsigned integer equivalent of type <tt>ty2</tt>.
2880</p>
2881
2882<h5>Arguments:</h5>
2883<p>The '<tt>fp2uint</tt>' instruction takes a value to cast, which must be a
2884<a href="#t_floating">floating point</a> value, and a type to cast it to, which
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame^]2885must be an <a href="#t_integer">integer</a> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2886
2887<h5>Semantics:</h5>
2888<p> The '<tt>fp2uint</tt>' instruction converts its
2889<a href="#t_floating">floating point</a> operand into the nearest (rounding
2890towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
2891the results are undefined.</p>
2892
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2893<p>When converting to i1, the conversion is done as a comparison against
2894zero. If the <tt>value</tt> was zero, the i1 result will be <tt>false</tt>.
2895If the <tt>value</tt> was non-zero, the i1 result will be <tt>true</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2896
2897<h5>Example:</h5>
2898<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2899 %X = fp2uint double 123.0 to i32 <i>; yields i32:123</i>
2900 %Y = fp2uint float 1.0E+300 to i1 <i>; yields i1:true</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2901 %X = fp2uint float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2902</pre>
2903</div>
2904
2905<!-- _______________________________________________________________________ -->
2906<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2907 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2908</div>
2909<div class="doc_text">
2910
2911<h5>Syntax:</h5>
2912<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2913 &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]2914</pre>
2915
2916<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2917<p>The '<tt>fptosi</tt>' instruction converts
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2918<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]2919</p>
2920
2921
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2922<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2923<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]2924<a href="#t_floating">floating point</a> value, and a type to cast it to, which
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame^]2925must also be an <a href="#t_integer">integer</a> type.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2926
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2927<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2928<p>The '<tt>fptosi</tt>' instruction converts its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2929<a href="#t_floating">floating point</a> operand into the nearest (rounding
2930towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
2931the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2932
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2933<p>When converting to i1, the conversion is done as a comparison against
2934zero. If the <tt>value</tt> was zero, the i1 result will be <tt>false</tt>.
2935If the <tt>value</tt> was non-zero, the i1 result will be <tt>true</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2936
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2937<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2938<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2939 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
2940 %Y = fptosi float 1.0E-247 to i1 <i>; yields i1:true</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2941 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2942</pre>
2943</div>
2944
2945<!-- _______________________________________________________________________ -->
2946<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2947 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2948</div>
2949<div class="doc_text">
2950
2951<h5>Syntax:</h5>
2952<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2953 &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]2954</pre>
2955
2956<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2957<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2958integer and converts that value to the <tt>ty2</tt> type.</p>
2959
2960
2961<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2962<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be an
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame^]2963<a href="#t_integer">integer</a> value, and a type to cast it to, which must
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2964be a <a href="#t_floating">floating point</a> type.</p>
2965
2966<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2967<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2968integer quantity and converts it to the corresponding floating point value. If
2969the value cannot fit in the floating point value, the results are undefined.</p>
2970
2971
2972<h5>Example:</h5>
2973<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2974 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
2975 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2976</pre>
2977</div>
2978
2979<!-- _______________________________________________________________________ -->
2980<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2981 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2982</div>
2983<div class="doc_text">
2984
2985<h5>Syntax:</h5>
2986<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2987 &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]2988</pre>
2989
2990<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2991<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2992integer and converts that value to the <tt>ty2</tt> type.</p>
2993
2994<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2995<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be an
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame^]2996<a href="#t_integer">integer</a> value, and a type to cast it to, which must be
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2997a <a href="#t_floating">floating point</a> type.</p>
2998
2999<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3000<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3001integer quantity and converts it to the corresponding floating point value. If
3002the value cannot fit in the floating point value, the results are undefined.</p>
3003
3004<h5>Example:</h5>
3005<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3006 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
3007 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3008</pre>
3009</div>
3010
3011<!-- _______________________________________________________________________ -->
3012<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3013 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3014</div>
3015<div class="doc_text">
3016
3017<h5>Syntax:</h5>
3018<pre>
3019 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3020</pre>
3021
3022<h5>Overview:</h5>
3023<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3024the integer type <tt>ty2</tt>.</p>
3025
3026<h5>Arguments:</h5>
3027<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
3028must be a <a href="t_pointer">pointer</a> value, and a type to cast it to
3029<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
3030
3031<h5>Semantics:</h5>
3032<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3033<tt>ty2</tt> by interpreting the pointer value as an integer and either
3034truncating or zero extending that value to the size of the integer type. If
3035<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3036<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
3037are the same size, then nothing is done (<i>no-op cast</i>).</p>
3038
3039<h5>Example:</h5>
3040<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3041 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit</i>
3042 %Y = ptrtoint i32* %x to i64 <i>; yields zero extend on 32-bit</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3043</pre>
3044</div>
3045
3046<!-- _______________________________________________________________________ -->
3047<div class="doc_subsubsection">
3048 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3049</div>
3050<div class="doc_text">
3051
3052<h5>Syntax:</h5>
3053<pre>
3054 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3055</pre>
3056
3057<h5>Overview:</h5>
3058<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3059a pointer type, <tt>ty2</tt>.</p>
3060
3061<h5>Arguments:</h5>
3062<p>The '<tt>inttoptr</tt>' instruction takes an <a href="i_integer">integer</a>
3063value to cast, and a type to cast it to, which must be a
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]3064<a href="#t_pointer">pointer</a> type.
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3065
3066<h5>Semantics:</h5>
3067<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3068<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3069the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3070size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3071the size of a pointer then a zero extension is done. If they are the same size,
3072nothing is done (<i>no-op cast</i>).</p>
3073
3074<h5>Example:</h5>
3075<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3076 %X = inttoptr i32 255 to i32* <i>; yields zero extend on 64-bit</i>
3077 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit </i>
3078 %Y = inttoptr i16 0 to i32* <i>; yields zero extend on 32-bit</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3079</pre>
3080</div>
3081
3082<!-- _______________________________________________________________________ -->
3083<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3084 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3085</div>
3086<div class="doc_text">
3087
3088<h5>Syntax:</h5>
3089<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3090 &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]3091</pre>
3092
3093<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3094<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3095<tt>ty2</tt> without changing any bits.</p>
3096
3097<h5>Arguments:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3098<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3099a first class value, and a type to cast it to, which must also be a <a
3100 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
Reid Spencer19b569f2007-01-09 20:08:58 +0000[diff] [blame]3101and the destination type, <tt>ty2</tt>, must be identical. If the source
3102type is a pointer, the destination type must also be a pointer.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3103
3104<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3105<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3106<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3107this conversion. The conversion is done as if the <tt>value</tt> had been
3108stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3109converted to other pointer types with this instruction. To convert pointers to
3110other types, use the <a href="#i_inttoptr">inttoptr</a> or
3111<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3112
3113<h5>Example:</h5>
3114<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3115 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
3116 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
3117 %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3118</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3119</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3120
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3121<!-- ======================================================================= -->
3122<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3123<div class="doc_text">
3124<p>The instructions in this category are the "miscellaneous"
3125instructions, which defy better classification.</p>
3126</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3127
3128<!-- _______________________________________________________________________ -->
3129<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3130</div>
3131<div class="doc_text">
3132<h5>Syntax:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3133<pre> &lt;result&gt; = icmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt;
3134<i>; yields {i1}:result</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3135</pre>
3136<h5>Overview:</h5>
3137<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
3138of its two integer operands.</p>
3139<h5>Arguments:</h5>
3140<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
3141the condition code which indicates the kind of comparison to perform. It is not
3142a value, just a keyword. The possibilities for the condition code are:
3143<ol>
3144 <li><tt>eq</tt>: equal</li>
3145 <li><tt>ne</tt>: not equal </li>
3146 <li><tt>ugt</tt>: unsigned greater than</li>
3147 <li><tt>uge</tt>: unsigned greater or equal</li>
3148 <li><tt>ult</tt>: unsigned less than</li>
3149 <li><tt>ule</tt>: unsigned less or equal</li>
3150 <li><tt>sgt</tt>: signed greater than</li>
3151 <li><tt>sge</tt>: signed greater or equal</li>
3152 <li><tt>slt</tt>: signed less than</li>
3153 <li><tt>sle</tt>: signed less or equal</li>
3154</ol>
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame^]3155<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3156<a href="#t_pointer">pointer</a> typed. They must also be identical types.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3157<h5>Semantics:</h5>
3158<p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3159the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3160yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3161<ol>
3162 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3163 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3164 </li>
3165 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3166 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3167 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3168 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3169 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3170 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3171 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3172 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3173 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3174 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3175 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3176 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3177 <li><tt>sge</tt>: interprets the operands as signed values and yields
3178 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3179 <li><tt>slt</tt>: interprets the operands as signed values and yields
3180 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3181 <li><tt>sle</tt>: interprets the operands as signed values and yields
3182 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3183</ol>
3184<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
3185values are treated as integers and then compared.</p>
3186<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]3187the vector are compared in turn and the predicate must hold for all
3188elements.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3189
3190<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3191<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3192 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3193 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3194 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3195 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3196 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3197</pre>
3198</div>
3199
3200<!-- _______________________________________________________________________ -->
3201<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3202</div>
3203<div class="doc_text">
3204<h5>Syntax:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3205<pre> &lt;result&gt; = fcmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt;
3206<i>; yields {i1}:result</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3207</pre>
3208<h5>Overview:</h5>
3209<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3210of its floating point operands.</p>
3211<h5>Arguments:</h5>
3212<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
3213the condition code which indicates the kind of comparison to perform. It is not
3214a value, just a keyword. The possibilities for the condition code are:
3215<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3216 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3217 <li><tt>oeq</tt>: ordered and equal</li>
3218 <li><tt>ogt</tt>: ordered and greater than </li>
3219 <li><tt>oge</tt>: ordered and greater than or equal</li>
3220 <li><tt>olt</tt>: ordered and less than </li>
3221 <li><tt>ole</tt>: ordered and less than or equal</li>
3222 <li><tt>one</tt>: ordered and not equal</li>
3223 <li><tt>ord</tt>: ordered (no nans)</li>
3224 <li><tt>ueq</tt>: unordered or equal</li>
3225 <li><tt>ugt</tt>: unordered or greater than </li>
3226 <li><tt>uge</tt>: unordered or greater than or equal</li>
3227 <li><tt>ult</tt>: unordered or less than </li>
3228 <li><tt>ule</tt>: unordered or less than or equal</li>
3229 <li><tt>une</tt>: unordered or not equal</li>
3230 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3231 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3232</ol>
Reid Spencer93a49852006-12-06 07:08:07 +0000[diff] [blame]3233<p>In the preceding, <i>ordered</i> means that neither operand is a QNAN while
3234<i>unordered</i> means that either operand may be a QNAN.</p>
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3235<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be
3236<a href="#t_floating">floating point</a> typed. They must have identical
3237types.</p>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3238<p>In the foregoing, <i>ordered</i> means that neither operand is a QNAN and
3239<i>unordered</i> means that either operand is a QNAN.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3240<h5>Semantics:</h5>
3241<p>The '<tt>fcmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3242the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3243yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3244<ol>
3245 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3246 <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]3247 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3248 <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]3249 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3250 <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]3251 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3252 <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]3253 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3254 <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]3255 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3256 <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]3257 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3258 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3259 <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]3260 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3261 <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]3262 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3263 <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]3264 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3265 <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]3266 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3267 <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]3268 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3269 <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]3270 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3271 <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]3272 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3273</ol>
3274<p>If the operands are <a href="#t_packed">packed</a> typed, the elements of
3275the vector are compared in turn and the predicate must hold for all elements.
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3276</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3277
3278<h5>Example:</h5>
3279<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3280 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3281 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3282 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3283</pre>
3284</div>
3285
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3286<!-- _______________________________________________________________________ -->
3287<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
3288Instruction</a> </div>
3289<div class="doc_text">
3290<h5>Syntax:</h5>
3291<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
3292<h5>Overview:</h5>
3293<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
3294the SSA graph representing the function.</p>
3295<h5>Arguments:</h5>
3296<p>The type of the incoming values are specified with the first type
3297field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
3298as arguments, with one pair for each predecessor basic block of the
3299current block. Only values of <a href="#t_firstclass">first class</a>
3300type may be used as the value arguments to the PHI node. Only labels
3301may be used as the label arguments.</p>
3302<p>There must be no non-phi instructions between the start of a basic
3303block and the PHI instructions: i.e. PHI instructions must be first in
3304a basic block.</p>
3305<h5>Semantics:</h5>
3306<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the
3307value specified by the parameter, depending on which basic block we
3308came from in the last <a href="#terminators">terminator</a> instruction.</p>
3309<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3310<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]3311</div>
3312
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3313<!-- _______________________________________________________________________ -->
3314<div class="doc_subsubsection">
3315 <a name="i_select">'<tt>select</tt>' Instruction</a>
3316</div>
3317
3318<div class="doc_text">
3319
3320<h5>Syntax:</h5>
3321
3322<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3323 &lt;result&gt; = select i1 &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3324</pre>
3325
3326<h5>Overview:</h5>
3327
3328<p>
3329The '<tt>select</tt>' instruction is used to choose one value based on a
3330condition, without branching.
3331</p>
3332
3333
3334<h5>Arguments:</h5>
3335
3336<p>
3337The '<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.
3338</p>
3339
3340<h5>Semantics:</h5>
3341
3342<p>
3343If the boolean condition evaluates to true, the instruction returns the first
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3344value argument; otherwise, it returns the second value argument.
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3345</p>
3346
3347<h5>Example:</h5>
3348
3349<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3350 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3351</pre>
3352</div>
3353
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]3354
3355<!-- _______________________________________________________________________ -->
3356<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3357 <a name="i_call">'<tt>call</tt>' Instruction</a>
3358</div>
3359
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3360<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3361
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3362<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3363<pre>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3364 &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]3365</pre>
3366
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3367<h5>Overview:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3368
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3369<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3370
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3371<h5>Arguments:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3372
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3373<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3374
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3375<ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3376 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3377 <p>The optional "tail" marker indicates whether the callee function accesses
3378 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3379 function call is eligible for tail call optimization. Note that calls may
3380 be marked "tail" even if they do not occur before a <a
3381 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3382 </li>
3383 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3384 <p>The optional "cconv" marker indicates which <a href="callingconv">calling
3385 convention</a> the call should use. If none is specified, the call defaults
3386 to using C calling conventions.
3387 </li>
3388 <li>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3389 <p>'<tt>ty</tt>': shall be the signature of the pointer to function value
3390 being invoked. The argument types must match the types implied by this
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3391 signature. This type can be omitted if the function is not varargs and
3392 if the function type does not return a pointer to a function.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3393 </li>
3394 <li>
3395 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
3396 be invoked. In most cases, this is a direct function invocation, but
3397 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3398 to function value.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3399 </li>
3400 <li>
3401 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencera7e302a2005-05-01 22:22:57 +0000[diff] [blame]3402 function signature argument types. All arguments must be of
3403 <a href="#t_firstclass">first class</a> type. If the function signature
3404 indicates the function accepts a variable number of arguments, the extra
3405 arguments can be specified.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3406 </li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3407</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3408
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3409<h5>Semantics:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3410
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3411<p>The '<tt>call</tt>' instruction is used to cause control flow to
3412transfer to a specified function, with its incoming arguments bound to
3413the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
3414instruction in the called function, control flow continues with the
3415instruction after the function call, and the return value of the
3416function is bound to the result argument. This is a simpler case of
3417the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3418
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3419<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3420
3421<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3422 %retval = call i32 %test(i32 %argc)
3423 call i32(i8 *, ...) *%printf(i8 * %msg, i32 12, i8 42);
3424 %X = tail call i32 %foo()
3425 %Y = tail call <a href="#callingconv">fastcc</a> i32 %foo()
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3426</pre>
3427
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3428</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3429
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3430<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3431<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3432 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3433</div>
3434
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3435<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3436
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3437<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3438
3439<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3440 &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]3441</pre>
3442
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3443<h5>Overview:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3444
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3445<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3446the "variable argument" area of a function call. It is used to implement the
3447<tt>va_arg</tt> macro in C.</p>
3448
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3449<h5>Arguments:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3450
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3451<p>This instruction takes a <tt>va_list*</tt> value and the type of
3452the argument. It returns a value of the specified argument type and
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]3453increments the <tt>va_list</tt> to point to the next argument. Again, the
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3454actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3455
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3456<h5>Semantics:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3457
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3458<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
3459type from the specified <tt>va_list</tt> and causes the
3460<tt>va_list</tt> to point to the next argument. For more information,
3461see the variable argument handling <a href="#int_varargs">Intrinsic
3462Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3463
3464<p>It is legal for this instruction to be called in a function which does not
3465take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3466function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3467
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3468<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3469href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3470argument.</p>
3471
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3472<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3473
3474<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
3475
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3476</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3477
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3478<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3479<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
3480<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3481
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3482<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3483
3484<p>LLVM supports the notion of an "intrinsic function". These functions have
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3485well known names and semantics and are required to follow certain
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3486restrictions. Overall, these instructions represent an extension mechanism for
3487the LLVM language that does not require changing all of the transformations in
3488LLVM to add to the language (or the bytecode reader/writer, the parser,
3489etc...).</p>
3490
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3491<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
3492prefix is reserved in LLVM for intrinsic names; thus, functions may not be named
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3493this. Intrinsic functions must always be external functions: you cannot define
3494the body of intrinsic functions. Intrinsic functions may only be used in call
3495or invoke instructions: it is illegal to take the address of an intrinsic
3496function. Additionally, because intrinsic functions are part of the LLVM
3497language, it is required that they all be documented here if any are added.</p>
3498
3499
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3500<p>To learn how to add an intrinsic function, please see the <a
Chris Lattner590cff32005-05-11 03:35:57 +0000[diff] [blame]3501href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3502</p>
3503
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3504</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3505
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3506<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3507<div class="doc_subsection">
3508 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
3509</div>
3510
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3511<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3512
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3513<p>Variable argument support is defined in LLVM with the <a
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3514 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3515intrinsic functions. These functions are related to the similarly
3516named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3517
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3518<p>All of these functions operate on arguments that use a
3519target-specific value type "<tt>va_list</tt>". The LLVM assembly
3520language reference manual does not define what this type is, so all
3521transformations should be prepared to handle intrinsics with any type
3522used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3523
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]3524<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]3525instruction and the variable argument handling intrinsic functions are
3526used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3527
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3528<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3529define i32 %test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3530 ; Initialize variable argument processing
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3531 %ap = alloca i8 *
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3532 %ap2 = bitcast i8** %ap to i8*
3533 call void %<a href="#i_va_start">llvm.va_start</a>(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3534
3535 ; Read a single integer argument
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3536 %tmp = va_arg i8 ** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3537
3538 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3539 %aq = alloca i8 *
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3540 %aq2 = bitcast i8** %aq to i8*
3541 call void %<a href="#i_va_copy">llvm.va_copy</a>(i8 *%aq2, i8* %ap2)
3542 call void %<a href="#i_va_end">llvm.va_end</a>(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3543
3544 ; Stop processing of arguments.
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3545 call void %<a href="#i_va_end">llvm.va_end</a>(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3546 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3547}
3548</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3549</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3550
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3551<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3552<div class="doc_subsubsection">
3553 <a name="i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
3554</div>
3555
3556
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3557<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3558<h5>Syntax:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3559<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3560<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3561<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
3562<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
3563href="#i_va_arg">va_arg</a></tt>.</p>
3564
3565<h5>Arguments:</h5>
3566
3567<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
3568
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3569<h5>Semantics:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3570
3571<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
3572macro available in C. In a target-dependent way, it initializes the
3573<tt>va_list</tt> element the argument points to, so that the next call to
3574<tt>va_arg</tt> will produce the first variable argument passed to the function.
3575Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
3576last argument of the function, the compiler can figure that out.</p>
3577
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3578</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3579
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3580<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3581<div class="doc_subsubsection">
3582 <a name="i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
3583</div>
3584
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3585<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3586<h5>Syntax:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3587<pre> declare void %llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3588<h5>Overview:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3589
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3590<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>&lt;arglist&gt;</tt>
3591which has been initialized previously with <tt><a href="#i_va_start">llvm.va_start</a></tt>
3592or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3593
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3594<h5>Arguments:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3595
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3596<p>The argument is a <tt>va_list</tt> to destroy.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3597
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3598<h5>Semantics:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3599
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3600<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]3601macro available in C. In a target-dependent way, it destroys the <tt>va_list</tt>.
3602Calls to <a href="#i_va_start"><tt>llvm.va_start</tt></a> and <a
3603 href="#i_va_copy"><tt>llvm.va_copy</tt></a> must be matched exactly
3604with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3605
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3606</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3607
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3608<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3609<div class="doc_subsubsection">
3610 <a name="i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
3611</div>
3612
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3613<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3614
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3615<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3616
3617<pre>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3618 declare void %llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3619</pre>
3620
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3621<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3622
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3623<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position from
3624the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3625
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3626<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3627
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3628<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
Andrew Lenharthd0a4c622005-06-22 20:38:11 +0000[diff] [blame]3629The 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]3630
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3631
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3632<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3633
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3634<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt> macro
3635available in C. In a target-dependent way, it copies the source
3636<tt>va_list</tt> element into the destination list. This intrinsic is necessary
3637because 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]3638arbitrarily complex and require memory allocation, for example.</p>
3639
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3640</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3641
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3642<!-- ======================================================================= -->
3643<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3644 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
3645</div>
3646
3647<div class="doc_text">
3648
3649<p>
3650LLVM support for <a href="GarbageCollection.html">Accurate Garbage
3651Collection</a> requires the implementation and generation of these intrinsics.
3652These intrinsics allow identification of <a href="#i_gcroot">GC roots on the
3653stack</a>, as well as garbage collector implementations that require <a
3654href="#i_gcread">read</a> and <a href="#i_gcwrite">write</a> barriers.
3655Front-ends for type-safe garbage collected languages should generate these
3656intrinsics to make use of the LLVM garbage collectors. For more details, see <a
3657href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
3658</p>
3659</div>
3660
3661<!-- _______________________________________________________________________ -->
3662<div class="doc_subsubsection">
3663 <a name="i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
3664</div>
3665
3666<div class="doc_text">
3667
3668<h5>Syntax:</h5>
3669
3670<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]3671 declare void %llvm.gcroot(&lt;ty&gt;** %ptrloc, &lt;ty2&gt;* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3672</pre>
3673
3674<h5>Overview:</h5>
3675
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]3676<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]3677the code generator, and allows some metadata to be associated with it.</p>
3678
3679<h5>Arguments:</h5>
3680
3681<p>The first argument specifies the address of a stack object that contains the
3682root pointer. The second pointer (which must be either a constant or a global
3683value address) contains the meta-data to be associated with the root.</p>
3684
3685<h5>Semantics:</h5>
3686
3687<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
3688location. At compile-time, the code generator generates information to allow
3689the runtime to find the pointer at GC safe points.
3690</p>
3691
3692</div>
3693
3694
3695<!-- _______________________________________________________________________ -->
3696<div class="doc_subsubsection">
3697 <a name="i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
3698</div>
3699
3700<div class="doc_text">
3701
3702<h5>Syntax:</h5>
3703
3704<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3705 declare i8 * %llvm.gcread(i8 * %ObjPtr, i8 ** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3706</pre>
3707
3708<h5>Overview:</h5>
3709
3710<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
3711locations, allowing garbage collector implementations that require read
3712barriers.</p>
3713
3714<h5>Arguments:</h5>
3715
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3716<p>The second argument is the address to read from, which should be an address
3717allocated from the garbage collector. The first object is a pointer to the
3718start of the referenced object, if needed by the language runtime (otherwise
3719null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3720
3721<h5>Semantics:</h5>
3722
3723<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
3724instruction, but may be replaced with substantially more complex code by the
3725garbage collector runtime, as needed.</p>
3726
3727</div>
3728
3729
3730<!-- _______________________________________________________________________ -->
3731<div class="doc_subsubsection">
3732 <a name="i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
3733</div>
3734
3735<div class="doc_text">
3736
3737<h5>Syntax:</h5>
3738
3739<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3740 declare void %llvm.gcwrite(i8 * %P1, i8 * %Obj, i8 ** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3741</pre>
3742
3743<h5>Overview:</h5>
3744
3745<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
3746locations, allowing garbage collector implementations that require write
3747barriers (such as generational or reference counting collectors).</p>
3748
3749<h5>Arguments:</h5>
3750
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3751<p>The first argument is the reference to store, the second is the start of the
3752object to store it to, and the third is the address of the field of Obj to
3753store to. If the runtime does not require a pointer to the object, Obj may be
3754null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3755
3756<h5>Semantics:</h5>
3757
3758<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
3759instruction, but may be replaced with substantially more complex code by the
3760garbage collector runtime, as needed.</p>
3761
3762</div>
3763
3764
3765
3766<!-- ======================================================================= -->
3767<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3768 <a name="int_codegen">Code Generator Intrinsics</a>
3769</div>
3770
3771<div class="doc_text">
3772<p>
3773These intrinsics are provided by LLVM to expose special features that may only
3774be implemented with code generator support.
3775</p>
3776
3777</div>
3778
3779<!-- _______________________________________________________________________ -->
3780<div class="doc_subsubsection">
3781 <a name="i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
3782</div>
3783
3784<div class="doc_text">
3785
3786<h5>Syntax:</h5>
3787<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3788 declare i8 *%llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3789</pre>
3790
3791<h5>Overview:</h5>
3792
3793<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]3794The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
3795target-specific value indicating the return address of the current function
3796or one of its callers.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3797</p>
3798
3799<h5>Arguments:</h5>
3800
3801<p>
3802The argument to this intrinsic indicates which function to return the address
3803for. Zero indicates the calling function, one indicates its caller, etc. The
3804argument is <b>required</b> to be a constant integer value.
3805</p>
3806
3807<h5>Semantics:</h5>
3808
3809<p>
3810The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
3811the return address of the specified call frame, or zero if it cannot be
3812identified. The value returned by this intrinsic is likely to be incorrect or 0
3813for arguments other than zero, so it should only be used for debugging purposes.
3814</p>
3815
3816<p>
3817Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]3818aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3819source-language caller.
3820</p>
3821</div>
3822
3823
3824<!-- _______________________________________________________________________ -->
3825<div class="doc_subsubsection">
3826 <a name="i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
3827</div>
3828
3829<div class="doc_text">
3830
3831<h5>Syntax:</h5>
3832<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3833 declare i8 *%llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3834</pre>
3835
3836<h5>Overview:</h5>
3837
3838<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]3839The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
3840target-specific frame pointer value for the specified stack frame.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3841</p>
3842
3843<h5>Arguments:</h5>
3844
3845<p>
3846The argument to this intrinsic indicates which function to return the frame
3847pointer for. Zero indicates the calling function, one indicates its caller,
3848etc. The argument is <b>required</b> to be a constant integer value.
3849</p>
3850
3851<h5>Semantics:</h5>
3852
3853<p>
3854The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
3855the frame address of the specified call frame, or zero if it cannot be
3856identified. The value returned by this intrinsic is likely to be incorrect or 0
3857for arguments other than zero, so it should only be used for debugging purposes.
3858</p>
3859
3860<p>
3861Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]3862aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3863source-language caller.
3864</p>
3865</div>
3866
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3867<!-- _______________________________________________________________________ -->
3868<div class="doc_subsubsection">
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]3869 <a name="i_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
3870</div>
3871
3872<div class="doc_text">
3873
3874<h5>Syntax:</h5>
3875<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3876 declare i8 *%llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]3877</pre>
3878
3879<h5>Overview:</h5>
3880
3881<p>
3882The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
3883the function stack, for use with <a href="#i_stackrestore">
3884<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
3885features like scoped automatic variable sized arrays in C99.
3886</p>
3887
3888<h5>Semantics:</h5>
3889
3890<p>
3891This intrinsic returns a opaque pointer value that can be passed to <a
3892href="#i_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
3893<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
3894<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
3895state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
3896practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
3897that were allocated after the <tt>llvm.stacksave</tt> was executed.
3898</p>
3899
3900</div>
3901
3902<!-- _______________________________________________________________________ -->
3903<div class="doc_subsubsection">
3904 <a name="i_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
3905</div>
3906
3907<div class="doc_text">
3908
3909<h5>Syntax:</h5>
3910<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3911 declare void %llvm.stackrestore(i8 * %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]3912</pre>
3913
3914<h5>Overview:</h5>
3915
3916<p>
3917The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
3918the function stack to the state it was in when the corresponding <a
3919href="#llvm.stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
3920useful for implementing language features like scoped automatic variable sized
3921arrays in C99.
3922</p>
3923
3924<h5>Semantics:</h5>
3925
3926<p>
3927See the description for <a href="#i_stacksave"><tt>llvm.stacksave</tt></a>.
3928</p>
3929
3930</div>
3931
3932
3933<!-- _______________________________________________________________________ -->
3934<div class="doc_subsubsection">
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3935 <a name="i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
3936</div>
3937
3938<div class="doc_text">
3939
3940<h5>Syntax:</h5>
3941<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3942 declare void %llvm.prefetch(i8 * &lt;address&gt;,
3943 i32 &lt;rw&gt;, i32 &lt;locality&gt;)
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3944</pre>
3945
3946<h5>Overview:</h5>
3947
3948
3949<p>
3950The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3951a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
3952no
3953effect on the behavior of the program but can change its performance
Chris Lattner2a615362005-02-28 19:47:14 +0000[diff] [blame]3954characteristics.
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3955</p>
3956
3957<h5>Arguments:</h5>
3958
3959<p>
3960<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
3961determining if the fetch should be for a read (0) or write (1), and
3962<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattneraeffb4a2005-03-07 20:31:38 +0000[diff] [blame]3963locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3964<tt>locality</tt> arguments must be constant integers.
3965</p>
3966
3967<h5>Semantics:</h5>
3968
3969<p>
3970This intrinsic does not modify the behavior of the program. In particular,
3971prefetches cannot trap and do not produce a value. On targets that support this
3972intrinsic, the prefetch can provide hints to the processor cache for better
3973performance.
3974</p>
3975
3976</div>
3977
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]3978<!-- _______________________________________________________________________ -->
3979<div class="doc_subsubsection">
3980 <a name="i_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
3981</div>
3982
3983<div class="doc_text">
3984
3985<h5>Syntax:</h5>
3986<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3987 declare void %llvm.pcmarker( i32 &lt;id&gt; )
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]3988</pre>
3989
3990<h5>Overview:</h5>
3991
3992
3993<p>
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3994The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
3995(PC) in a region of
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]3996code to simulators and other tools. The method is target specific, but it is
3997expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]3998The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnerd07c3f42005-11-15 06:07:55 +0000[diff] [blame]3999after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb3e7afd2006-03-24 07:16:10 +0000[diff] [blame]4000optimizations. The intended use is to be inserted after optimizations to allow
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4001correlations of simulation runs.
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4002</p>
4003
4004<h5>Arguments:</h5>
4005
4006<p>
4007<tt>id</tt> is a numerical id identifying the marker.
4008</p>
4009
4010<h5>Semantics:</h5>
4011
4012<p>
4013This intrinsic does not modify the behavior of the program. Backends that do not
4014support this intrinisic may ignore it.
4015</p>
4016
4017</div>
4018
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4019<!-- _______________________________________________________________________ -->
4020<div class="doc_subsubsection">
4021 <a name="i_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
4022</div>
4023
4024<div class="doc_text">
4025
4026<h5>Syntax:</h5>
4027<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4028 declare i64 %llvm.readcyclecounter( )
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4029</pre>
4030
4031<h5>Overview:</h5>
4032
4033
4034<p>
4035The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
4036counter register (or similar low latency, high accuracy clocks) on those targets
4037that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
4038As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
4039should only be used for small timings.
4040</p>
4041
4042<h5>Semantics:</h5>
4043
4044<p>
4045When directly supported, reading the cycle counter should not modify any memory.
4046Implementations are allowed to either return a application specific value or a
4047system wide value. On backends without support, this is lowered to a constant 0.
4048</p>
4049
4050</div>
4051
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4052<!-- ======================================================================= -->
4053<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4054 <a name="int_libc">Standard C Library Intrinsics</a>
4055</div>
4056
4057<div class="doc_text">
4058<p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4059LLVM provides intrinsics for a few important standard C library functions.
4060These intrinsics allow source-language front-ends to pass information about the
4061alignment of the pointer arguments to the code generator, providing opportunity
4062for more efficient code generation.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4063</p>
4064
4065</div>
4066
4067<!-- _______________________________________________________________________ -->
4068<div class="doc_subsubsection">
4069 <a name="i_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
4070</div>
4071
4072<div class="doc_text">
4073
4074<h5>Syntax:</h5>
4075<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4076 declare void %llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4077 i32 &lt;len&gt;, i32 &lt;align&gt;)
4078 declare void %llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4079 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4080</pre>
4081
4082<h5>Overview:</h5>
4083
4084<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4085The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4086location to the destination location.
4087</p>
4088
4089<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4090Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4091intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4092</p>
4093
4094<h5>Arguments:</h5>
4095
4096<p>
4097The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4098the source. The third argument is an integer argument
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4099specifying the number of bytes to copy, and the fourth argument is the alignment
4100of the source and destination locations.
4101</p>
4102
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4103<p>
4104If 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]4105the caller guarantees that both the source and destination pointers are aligned
4106to that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4107</p>
4108
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4109<h5>Semantics:</h5>
4110
4111<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4112The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4113location to the destination location, which are not allowed to overlap. It
4114copies "len" bytes of memory over. If the argument is known to be aligned to
4115some boundary, this can be specified as the fourth argument, otherwise it should
4116be set to 0 or 1.
4117</p>
4118</div>
4119
4120
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4121<!-- _______________________________________________________________________ -->
4122<div class="doc_subsubsection">
4123 <a name="i_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
4124</div>
4125
4126<div class="doc_text">
4127
4128<h5>Syntax:</h5>
4129<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4130 declare void %llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4131 i32 &lt;len&gt;, i32 &lt;align&gt;)
4132 declare void %llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4133 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4134</pre>
4135
4136<h5>Overview:</h5>
4137
4138<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4139The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
4140location to the destination location. It is similar to the
4141'<tt>llvm.memcmp</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4142</p>
4143
4144<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4145Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
4146intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4147</p>
4148
4149<h5>Arguments:</h5>
4150
4151<p>
4152The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4153the source. The third argument is an integer argument
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4154specifying the number of bytes to copy, and the fourth argument is the alignment
4155of the source and destination locations.
4156</p>
4157
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4158<p>
4159If 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]4160the caller guarantees that the source and destination pointers are aligned to
4161that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4162</p>
4163
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4164<h5>Semantics:</h5>
4165
4166<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4167The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4168location to the destination location, which may overlap. It
4169copies "len" bytes of memory over. If the argument is known to be aligned to
4170some boundary, this can be specified as the fourth argument, otherwise it should
4171be set to 0 or 1.
4172</p>
4173</div>
4174
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4175
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4176<!-- _______________________________________________________________________ -->
4177<div class="doc_subsubsection">
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4178 <a name="i_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4179</div>
4180
4181<div class="doc_text">
4182
4183<h5>Syntax:</h5>
4184<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4185 declare void %llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
4186 i32 &lt;len&gt;, i32 &lt;align&gt;)
4187 declare void %llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
4188 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4189</pre>
4190
4191<h5>Overview:</h5>
4192
4193<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4194The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4195byte value.
4196</p>
4197
4198<p>
4199Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
4200does not return a value, and takes an extra alignment argument.
4201</p>
4202
4203<h5>Arguments:</h5>
4204
4205<p>
4206The first argument is a pointer to the destination to fill, the second is the
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4207byte value to fill it with, the third argument is an integer
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4208argument specifying the number of bytes to fill, and the fourth argument is the
4209known alignment of destination location.
4210</p>
4211
4212<p>
4213If 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]4214the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4215</p>
4216
4217<h5>Semantics:</h5>
4218
4219<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4220The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
4221the
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4222destination location. If the argument is known to be aligned to some boundary,
4223this can be specified as the fourth argument, otherwise it should be set to 0 or
42241.
4225</p>
4226</div>
4227
4228
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4229<!-- _______________________________________________________________________ -->
4230<div class="doc_subsubsection">
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4231 <a name="i_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4232</div>
4233
4234<div class="doc_text">
4235
4236<h5>Syntax:</h5>
4237<pre>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4238 declare float %llvm.sqrt.f32(float %Val)
4239 declare double %llvm.sqrt.f64(double %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4240</pre>
4241
4242<h5>Overview:</h5>
4243
4244<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4245The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4246returning the same value as the libm '<tt>sqrt</tt>' function would. Unlike
4247<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
4248negative numbers (which allows for better optimization).
4249</p>
4250
4251<h5>Arguments:</h5>
4252
4253<p>
4254The argument and return value are floating point numbers of the same type.
4255</p>
4256
4257<h5>Semantics:</h5>
4258
4259<p>
4260This function returns the sqrt of the specified operand if it is a positive
4261floating point number.
4262</p>
4263</div>
4264
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4265<!-- _______________________________________________________________________ -->
4266<div class="doc_subsubsection">
4267 <a name="i_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
4268</div>
4269
4270<div class="doc_text">
4271
4272<h5>Syntax:</h5>
4273<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4274 declare float %llvm.powi.f32(float %Val, i32 %power)
4275 declare double %llvm.powi.f64(double %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4276</pre>
4277
4278<h5>Overview:</h5>
4279
4280<p>
4281The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
4282specified (positive or negative) power. The order of evaluation of
4283multiplications is not defined.
4284</p>
4285
4286<h5>Arguments:</h5>
4287
4288<p>
4289The second argument is an integer power, and the first is a value to raise to
4290that power.
4291</p>
4292
4293<h5>Semantics:</h5>
4294
4295<p>
4296This function returns the first value raised to the second power with an
4297unspecified sequence of rounding operations.</p>
4298</div>
4299
4300
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4301<!-- ======================================================================= -->
4302<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4303 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4304</div>
4305
4306<div class="doc_text">
4307<p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4308LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4309These allow efficient code generation for some algorithms.
4310</p>
4311
4312</div>
4313
4314<!-- _______________________________________________________________________ -->
4315<div class="doc_subsubsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4316 <a name="i_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
4317</div>
4318
4319<div class="doc_text">
4320
4321<h5>Syntax:</h5>
4322<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4323 declare i16 %llvm.bswap.i16(i16 &lt;id&gt;)
4324 declare i32 %llvm.bswap.i32(i32 &lt;id&gt;)
4325 declare i64 %llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4326</pre>
4327
4328<h5>Overview:</h5>
4329
4330<p>
4331The '<tt>llvm.bwsap</tt>' family of intrinsics is used to byteswap a 16, 32 or
433264 bit quantity. These are useful for performing operations on data that is not
4333in the target's native byte order.
4334</p>
4335
4336<h5>Semantics:</h5>
4337
4338<p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4339The <tt>llvm.bswap.16</tt> intrinsic returns an i16 value that has the high
4340and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
4341intrinsic returns an i32 value that has the four bytes of the input i32
4342swapped, so that if the input bytes are numbered 0, 1, 2, 3 then the returned
4343i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i64</tt>
4344intrinsic extends this concept to 64 bits.
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4345</p>
4346
4347</div>
4348
4349<!-- _______________________________________________________________________ -->
4350<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4351 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4352</div>
4353
4354<div class="doc_text">
4355
4356<h5>Syntax:</h5>
4357<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4358 declare i8 %llvm.ctpop.i8 (i8 &lt;src&gt;)
4359 declare i16 %llvm.ctpop.i16(i16 &lt;src&gt;)
4360 declare i32 %llvm.ctpop.i32(i32 &lt;src&gt;)
4361 declare i64 %llvm.ctpop.i64(i64 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4362</pre>
4363
4364<h5>Overview:</h5>
4365
4366<p>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4367The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
4368value.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4369</p>
4370
4371<h5>Arguments:</h5>
4372
4373<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]4374The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4375integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4376</p>
4377
4378<h5>Semantics:</h5>
4379
4380<p>
4381The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
4382</p>
4383</div>
4384
4385<!-- _______________________________________________________________________ -->
4386<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]4387 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4388</div>
4389
4390<div class="doc_text">
4391
4392<h5>Syntax:</h5>
4393<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4394 declare i8 %llvm.ctlz.i8 (i8 &lt;src&gt;)
4395 declare i16 %llvm.ctlz.i16(i16 &lt;src&gt;)
4396 declare i32 %llvm.ctlz.i32(i32 &lt;src&gt;)
4397 declare i64 %llvm.ctlz.i64(i64 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4398</pre>
4399
4400<h5>Overview:</h5>
4401
4402<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4403The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
4404leading zeros in a variable.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4405</p>
4406
4407<h5>Arguments:</h5>
4408
4409<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]4410The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4411integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4412</p>
4413
4414<h5>Semantics:</h5>
4415
4416<p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4417The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
4418in 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]4419of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4420</p>
4421</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4422
4423
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4424
4425<!-- _______________________________________________________________________ -->
4426<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]4427 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4428</div>
4429
4430<div class="doc_text">
4431
4432<h5>Syntax:</h5>
4433<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4434 declare i8 %llvm.cttz.i8 (i8 &lt;src&gt;)
4435 declare i16 %llvm.cttz.i16(i16 &lt;src&gt;)
4436 declare i32 %llvm.cttz.i32(i32 &lt;src&gt;)
4437 declare i64 %llvm.cttz.i64(i64 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4438</pre>
4439
4440<h5>Overview:</h5>
4441
4442<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4443The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
4444trailing zeros.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4445</p>
4446
4447<h5>Arguments:</h5>
4448
4449<p>
4450The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4451integer type. The return type must match the argument type.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4452</p>
4453
4454<h5>Semantics:</h5>
4455
4456<p>
4457The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
4458in a variable. If the src == 0 then the result is the size in bits of the type
4459of src. For example, <tt>llvm.cttz(2) = 1</tt>.
4460</p>
4461</div>
4462
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4463<!-- ======================================================================= -->
4464<div class="doc_subsection">
4465 <a name="int_debugger">Debugger Intrinsics</a>
4466</div>
4467
4468<div class="doc_text">
4469<p>
4470The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
4471are described in the <a
4472href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
4473Debugging</a> document.
4474</p>
4475</div>
4476
4477
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4478<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4479<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]4480<address>
4481 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
4482 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
4483 <a href="http://validator.w3.org/check/referer"><img
4484 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!" /></a>
4485
4486 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]4487 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]4488 Last modified: $Date$
4489</address>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4490</body>
4491</html>