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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / b592952fe9272c40b5e634ad05e198d9fb85a57a / . / 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
278 with quotes. In this way, anything except a <tt>"</tt> character can be used
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
427 '<tt>static</tt>' keyword in C, or the idea of "anonymous namespaces" 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
432 <dd>"<tt>linkonce</tt>" linkage is similar to <tt>internal</tt> linkage, with
433 the twist that linking together two modules defining the same
434 <tt>linkonce</tt> globals will cause one of the globals to be discarded. This
435 is typically used to implement inline functions. Unreferenced
436 <tt>linkonce</tt> globals are 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
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]443 used to implement constructs in C such as "<tt>i32 X;</tt>" at global scope.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]444 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]445
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]446 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]447
448 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
449 pointer to array type. When two global variables with appending linkage are
450 linked together, the two global arrays are appended together. This is the
451 LLVM, typesafe, equivalent of having the system linker append together
452 "sections" with identical names when .o files are linked.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]453 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]454
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]455 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]456
457 <dd>If none of the above identifiers are used, the global is externally
458 visible, meaning that it participates in linkage and can be used to resolve
459 external symbol references.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]460 </dd>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]461
462 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
463
464 <dd>"<tt>extern_weak</tt>" TBD
465 </dd>
466
467 <p>
468 The next two types of linkage are targeted for Microsoft Windows platform
469 only. They are designed to support importing (exporting) symbols from (to)
470 DLLs.
471 </p>
472
473 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
474
475 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
476 or variable via a global pointer to a pointer that is set up by the DLL
477 exporting the symbol. On Microsoft Windows targets, the pointer name is
478 formed by combining <code>_imp__</code> and the function or variable name.
479 </dd>
480
481 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
482
483 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
484 pointer to a pointer in a DLL, so that it can be referenced with the
485 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
486 name is formed by combining <code>_imp__</code> and the function or variable
487 name.
488 </dd>
489
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]490</dl>
491
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]492<p><a name="linkage_external">For example, since the "<tt>.LC0</tt>"
493variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
494variable and was linked with this one, one of the two would be renamed,
495preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
496external (i.e., lacking any linkage declarations), they are accessible
Reid Spencerac8d2762007-01-05 00:59:10 +0000[diff] [blame]497outside of the current module.</p>
498<p>It is illegal for a function <i>declaration</i>
499to have any linkage type other than "externally visible", <tt>dllimport</tt>,
500or <tt>extern_weak</tt>.</a></p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]501
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]502</div>
503
504<!-- ======================================================================= -->
505<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]506 <a name="callingconv">Calling Conventions</a>
507</div>
508
509<div class="doc_text">
510
511<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
512and <a href="#i_invoke">invokes</a> can all have an optional calling convention
513specified for the call. The calling convention of any pair of dynamic
514caller/callee must match, or the behavior of the program is undefined. The
515following calling conventions are supported by LLVM, and more may be added in
516the future:</p>
517
518<dl>
519 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
520
521 <dd>This calling convention (the default if no other calling convention is
522 specified) matches the target C calling conventions. This calling convention
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]523 supports varargs function calls and tolerates some mismatch in the declared
Reid Spencerc28d2bc2006-12-31 21:30:18 +0000[diff] [blame]524 prototype and implemented declaration of the function (as does normal C).
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]525 </dd>
526
Chris Lattner5710ce92006-05-19 21:15:36 +0000[diff] [blame]527 <dt><b>"<tt>csretcc</tt>" - The C struct return calling convention</b>:</dt>
528
529 <dd>This calling convention matches the target C calling conventions, except
530 that functions with this convention are required to take a pointer as their
531 first argument, and the return type of the function must be void. This is
532 used for C functions that return aggregates by-value. In this case, the
533 function has been transformed to take a pointer to the struct as the first
534 argument to the function. For targets where the ABI specifies specific
535 behavior for structure-return calls, the calling convention can be used to
536 distinguish between struct return functions and other functions that take a
537 pointer to a struct as the first argument.
538 </dd>
539
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]540 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
541
542 <dd>This calling convention attempts to make calls as fast as possible
543 (e.g. by passing things in registers). This calling convention allows the
544 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner8cdc5bc2005-05-06 23:08:23 +0000[diff] [blame]545 without having to conform to an externally specified ABI. Implementations of
546 this convention should allow arbitrary tail call optimization to be supported.
547 This calling convention does not support varargs and requires the prototype of
548 all callees to exactly match the prototype of the function definition.
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]549 </dd>
550
551 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
552
553 <dd>This calling convention attempts to make code in the caller as efficient
554 as possible under the assumption that the call is not commonly executed. As
555 such, these calls often preserve all registers so that the call does not break
556 any live ranges in the caller side. This calling convention does not support
557 varargs and requires the prototype of all callees to exactly match the
558 prototype of the function definition.
559 </dd>
560
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]561 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]562
563 <dd>Any calling convention may be specified by number, allowing
564 target-specific calling conventions to be used. Target specific calling
565 conventions start at 64.
566 </dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]567</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]568
569<p>More calling conventions can be added/defined on an as-needed basis, to
570support pascal conventions or any other well-known target-independent
571convention.</p>
572
573</div>
574
575<!-- ======================================================================= -->
576<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]577 <a name="globalvars">Global Variables</a>
578</div>
579
580<div class="doc_text">
581
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]582<p>Global variables define regions of memory allocated at compilation time
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]583instead of run-time. Global variables may optionally be initialized, may have
584an explicit section to be placed in, and may
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]585have an optional explicit alignment specified. A
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]586variable may be defined as a global "constant," which indicates that the
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]587contents of the variable will <b>never</b> be modified (enabling better
588optimization, allowing the global data to be placed in the read-only section of
589an executable, etc). Note that variables that need runtime initialization
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]590cannot be marked "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]591
592<p>
593LLVM explicitly allows <em>declarations</em> of global variables to be marked
594constant, even if the final definition of the global is not. This capability
595can be used to enable slightly better optimization of the program, but requires
596the language definition to guarantee that optimizations based on the
597'constantness' are valid for the translation units that do not include the
598definition.
599</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]600
601<p>As SSA values, global variables define pointer values that are in
602scope (i.e. they dominate) all basic blocks in the program. Global
603variables always define a pointer to their "content" type because they
604describe a region of memory, and all memory objects in LLVM are
605accessed through pointers.</p>
606
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]607<p>LLVM allows an explicit section to be specified for globals. If the target
608supports it, it will emit globals to the section specified.</p>
609
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]610<p>An explicit alignment may be specified for a global. If not present, or if
611the alignment is set to zero, the alignment of the global is set by the target
612to whatever it feels convenient. If an explicit alignment is specified, the
613global is forced to have at least that much alignment. All alignments must be
614a power of 2.</p>
615
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]616</div>
617
618
619<!-- ======================================================================= -->
620<div class="doc_subsection">
621 <a name="functionstructure">Functions</a>
622</div>
623
624<div class="doc_text">
625
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]626<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
627an optional <a href="#linkage">linkage type</a>, an optional
628<a href="#callingconv">calling convention</a>, a return type, an optional
629<a href="#paramattrs">parameter attribute</a> for the return type, a function
630name, a (possibly empty) argument list (each with optional
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]631<a href="#paramattrs">parameter attributes</a>), an optional section, an
632optional alignment, an opening curly brace, a list of basic blocks, and a
633closing curly brace. LLVM function declarations
634consist of the "<tt>declare</tt>" keyword, an optional <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]635 href="#callingconv">calling convention</a>, a return type, an optional
636<a href="#paramattrs">parameter attribute</a> for the return type, a function
637name, a possibly empty list of arguments, and an optional alignment.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]638
639<p>A function definition contains a list of basic blocks, forming the CFG for
640the function. Each basic block may optionally start with a label (giving the
641basic block a symbol table entry), contains a list of instructions, and ends
642with a <a href="#terminators">terminator</a> instruction (such as a branch or
643function return).</p>
644
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]645<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]646executed on entrance to the function, and it is not allowed to have predecessor
647basic blocks (i.e. there can not be any branches to the entry block of a
648function). Because the block can have no predecessors, it also cannot have any
649<a href="#i_phi">PHI nodes</a>.</p>
650
651<p>LLVM functions are identified by their name and type signature. Hence, two
652functions with the same name but different parameter lists or return values are
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]653considered different functions, and LLVM will resolve references to each
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]654appropriately.</p>
655
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]656<p>LLVM allows an explicit section to be specified for functions. If the target
657supports it, it will emit functions to the section specified.</p>
658
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]659<p>An explicit alignment may be specified for a function. If not present, or if
660the alignment is set to zero, the alignment of the function is set by the target
661to whatever it feels convenient. If an explicit alignment is specified, the
662function is forced to have at least that much alignment. All alignments must be
663a power of 2.</p>
664
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]665</div>
666
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]667<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]668<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
669<div class="doc_text">
670 <p>The return type and each parameter of a function type may have a set of
671 <i>parameter attributes</i> associated with them. Parameter attributes are
672 used to communicate additional information about the result or parameters of
673 a function. Parameter attributes are considered to be part of the function
674 type so two functions types that differ only by the parameter attributes
675 are different function types.</p>
676
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]677 <p>Parameter attributes consist of an at sign (@) followed by either a single
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]678 keyword or a comma separate list of keywords enclosed in parentheses. For
679 example:<pre>
680 %someFunc = i16 @zext (i8 @(sext) %someParam)
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]681 %someFunc = i16 @zext (i8 @zext %someParam)</pre>
682 Note that the two function types above are unique because the parameter
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]683 has a different attribute (@sext in the first one, @zext in the second).</p>
684
685 <p>Currently, only the following parameter attributes are defined:
686 <dl>
687 <dt><tt>@zext</tt></dt>
688 <dd>This indicates that the parameter should be zero extended just before
689 a call to this function.</dd>
690 <dt><tt>@sext</tt></dt>
691 <dd>This indicates that the parameter should be sign extended just before
692 a call to this function.</dd>
693 </dl></p>
694
695 <p>The current motivation for parameter attributes is to enable the sign and
696 zero extend information necessary for the C calling convention to be passed
697 from the front end to LLVM. The <tt>@zext</tt> and <tt>@sext</tt> attributes
698 are used by the code generator to perform the required extension. However,
699 parameter attributes are an orthogonal feature to calling conventions and
700 may be used for other purposes in the future.</p>
701</div>
702
703<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]704<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]705 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]706</div>
707
708<div class="doc_text">
709<p>
710Modules may contain "module-level inline asm" blocks, which corresponds to the
711GCC "file scope inline asm" blocks. These blocks are internally concatenated by
712LLVM and treated as a single unit, but may be separated in the .ll file if
713desired. The syntax is very simple:
714</p>
715
716<div class="doc_code"><pre>
Chris Lattner52599e12006-01-24 00:37:20 +0000[diff] [blame]717 module asm "inline asm code goes here"
718 module asm "more can go here"
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]719</pre></div>
720
721<p>The strings can contain any character by escaping non-printable characters.
722 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
723 for the number.
724</p>
725
726<p>
727 The inline asm code is simply printed to the machine code .s file when
728 assembly code is generated.
729</p>
730</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]731
732
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]733<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]734<div class="doc_section"> <a name="typesystem">Type System</a> </div>
735<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]736
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]737<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]738
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]739<p>The LLVM type system is one of the most important features of the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]740intermediate representation. Being typed enables a number of
741optimizations to be performed on the IR directly, without having to do
742extra analyses on the side before the transformation. A strong type
743system makes it easier to read the generated code and enables novel
744analyses and transformations that are not feasible to perform on normal
745three address code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]746
747</div>
748
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]749<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]750<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]751<div class="doc_text">
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]752<p>The primitive types are the fundamental building blocks of the LLVM
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]753system. The current set of primitive types is as follows:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]754
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]755<table class="layout">
756 <tr class="layout">
757 <td class="left">
758 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]759 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]760 <tr><th>Type</th><th>Description</th></tr>
761 <tr><td><tt>void</tt></td><td>No value</td></tr>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]762 <tr><td><tt>i8</tt></td><td>Signless 8-bit value</td></tr>
763 <tr><td><tt>i32</tt></td><td>Signless 32-bit value</td></tr>
Misha Brukmancfa87bc2005-04-22 18:02:52 +0000[diff] [blame]764 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]765 <tr><td><tt>label</tt></td><td>Branch destination</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]766 </tbody>
767 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]768 </td>
769 <td class="right">
770 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]771 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]772 <tr><th>Type</th><th>Description</th></tr>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]773 <tr><td><tt>i1</tt></td><td>True or False value</td></tr>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]774 <tr><td><tt>i16</tt></td><td>Signless 16-bit value</td></tr>
775 <tr><td><tt>i64</tt></td><td>Signless 64-bit value</td></tr>
776 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]777 </tbody>
778 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]779 </td>
780 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]781</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]782</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]783
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]784<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]785<div class="doc_subsubsection"> <a name="t_classifications">Type
786Classifications</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]787<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]788<p>These different primitive types fall into a few useful
789classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]790
791<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]792 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]793 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]794 <tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]795 <td><a name="t_integer">integer</a></td>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]796 <td><tt>i8, i16, i32, i64</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]797 </tr>
798 <tr>
799 <td><a name="t_integral">integral</a></td>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]800 <td><tt>i1, i8, i16, i32, i64</tt>
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]801 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]802 </tr>
803 <tr>
804 <td><a name="t_floating">floating point</a></td>
805 <td><tt>float, double</tt></td>
806 </tr>
807 <tr>
808 <td><a name="t_firstclass">first class</a></td>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]809 <td><tt>i1, i8, i16, i32, i64, float, double, <br/>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]810 <a href="#t_pointer">pointer</a>,<a href="#t_packed">packed</a></tt>
811 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]812 </tr>
813 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]814</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]815
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]816<p>The <a href="#t_firstclass">first class</a> types are perhaps the
817most important. Values of these types are the only ones which can be
818produced by instructions, passed as arguments, or used as operands to
819instructions. This means that all structures and arrays must be
820manipulated either by pointer or by component.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]821</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]822
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]823<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]824<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]825
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]826<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]827
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]828<p>The real power in LLVM comes from the derived types in the system.
829This is what allows a programmer to represent arrays, functions,
830pointers, and other useful types. Note that these derived types may be
831recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]832
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]833</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]834
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]835<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]836<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]837
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]838<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]839
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]840<h5>Overview:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]841
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]842<p>The array type is a very simple derived type that arranges elements
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]843sequentially in memory. The array type requires a size (number of
844elements) and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]845
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]846<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]847
848<pre>
849 [&lt;# elements&gt; x &lt;elementtype&gt;]
850</pre>
851
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]852<p>The number of elements is a constant integer value; elementtype may
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]853be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]854
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]855<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]856<table class="layout">
857 <tr class="layout">
858 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]859 <tt>[40 x i32 ]</tt><br/>
860 <tt>[41 x i32 ]</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]861 <tt>[40 x i8]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]862 </td>
863 <td class="left">
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]864 Array of 40 32-bit integer values.<br/>
865 Array of 41 32-bit integer values.<br/>
866 Array of 40 8-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]867 </td>
868 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]869</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]870<p>Here are some examples of multidimensional arrays:</p>
871<table class="layout">
872 <tr class="layout">
873 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]874 <tt>[3 x [4 x i32]]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]875 <tt>[12 x [10 x float]]</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]876 <tt>[2 x [3 x [4 x i16]]]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]877 </td>
878 <td class="left">
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]879 3x4 array of 32-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]880 12x10 array of single precision floating point values.<br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]881 2x3x4 array of 16-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]882 </td>
883 </tr>
884</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]885
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]886<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
887length array. Normally, accesses past the end of an array are undefined in
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]888LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
889As a special case, however, zero length arrays are recognized to be variable
890length. This allows implementation of 'pascal style arrays' with the LLVM
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]891type "{ i32, [0 x float]}", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]892
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]893</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]894
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]895<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]896<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]897<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]898<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]899<p>The function type can be thought of as a function signature. It
900consists of a return type and a list of formal parameter types.
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]901Function types are usually used to build virtual function tables
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]902(which are structures of pointers to functions), for indirect function
903calls, and when defining a function.</p>
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]904<p>
905The return type of a function type cannot be an aggregate type.
906</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]907<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]908<pre> &lt;returntype&gt; (&lt;parameter list&gt;)<br></pre>
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]909<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]910specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]911which indicates that the function takes a variable number of arguments.
912Variable argument functions can access their arguments with the <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]913 href="#int_varargs">variable argument handling intrinsic</a> functions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]914<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]915<table class="layout">
916 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]917 <td class="left"><tt>i32 (i32)</tt></td>
918 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]919 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]920 </tr><tr class="layout">
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]921 <td class="left"><tt>float&nbsp;(i16&nbsp;@sext,&nbsp;i32&nbsp;*)&nbsp;*
922 </tt></td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]923 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
924 an <tt>i16</tt> that should be sign extended and a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]925 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]926 <tt>float</tt>.
927 </td>
928 </tr><tr class="layout">
929 <td class="left"><tt>i32 (i8*, ...)</tt></td>
930 <td class="left">A vararg function that takes at least one
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]931 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]932 which returns an integer. This is the signature for <tt>printf</tt> in
933 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]934 </td>
935 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]936</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]937
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]938</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]939<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]940<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]941<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]942<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]943<p>The structure type is used to represent a collection of data members
944together in memory. The packing of the field types is defined to match
945the ABI of the underlying processor. The elements of a structure may
946be any type that has a size.</p>
947<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
948and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
949field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
950instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]951<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]952<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]953<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]954<table class="layout">
955 <tr class="layout">
956 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]957 <tt>{ i32, i32, i32 }</tt><br/>
958 <tt>{ float, i32 (i32) * }</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]959 </td>
960 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]961 a triple of three <tt>i32</tt> values<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]962 A pair, where the first element is a <tt>float</tt> and the second element
963 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]964 that takes an <tt>i32</tt>, returning an <tt>i32</tt>.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]965 </td>
966 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]967</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]968</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]969
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]970<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]971<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
972</div>
973<div class="doc_text">
974<h5>Overview:</h5>
975<p>The packed structure type is used to represent a collection of data members
976together in memory. There is no padding between fields. Further, the alignment
977of a packed structure is 1 byte. The elements of a packed structure may
978be any type that has a size.</p>
979<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
980and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
981field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
982instruction.</p>
983<h5>Syntax:</h5>
984<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
985<h5>Examples:</h5>
986<table class="layout">
987 <tr class="layout">
988 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]989 <tt> &lt; { i32, i32, i32 } &gt; </tt><br/>
990 <tt> &lt; { float, i32 (i32) * } &gt; </tt><br/>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]991 </td>
992 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]993 a triple of three <tt>i32</tt> values<br/>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]994 A pair, where the first element is a <tt>float</tt> and the second element
995 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]996 that takes an <tt>i32</tt>, returning an <tt>i32</tt>.<br/>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]997 </td>
998 </tr>
999</table>
1000</div>
1001
1002<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1003<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1004<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1005<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1006<p>As in many languages, the pointer type represents a pointer or
1007reference to another object, which must live in memory.</p>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1008<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1009<pre> &lt;type&gt; *<br></pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1010<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1011<table class="layout">
1012 <tr class="layout">
1013 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1014 <tt>[4x i32]*</tt><br/>
1015 <tt>i32 (i32 *) *</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1016 </td>
1017 <td class="left">
1018 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]1019 four <tt>i32</tt> values<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1020 A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1021 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
1022 <tt>i32</tt>.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1023 </td>
1024 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1025</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1026</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1027
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1028<!-- _______________________________________________________________________ -->
1029<div class="doc_subsubsection"> <a name="t_packed">Packed Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1030<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1031
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1032<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1033
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1034<p>A packed type is a simple derived type that represents a vector
1035of elements. Packed types are used when multiple primitive data
1036are operated in parallel using a single instruction (SIMD).
1037A packed type requires a size (number of
Chris Lattnerb8d172f2005-11-10 01:44:22 +0000[diff] [blame]1038elements) and an underlying primitive data type. Vectors must have a power
1039of two length (1, 2, 4, 8, 16 ...). Packed types are
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1040considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1041
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1042<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1043
1044<pre>
1045 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1046</pre>
1047
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1048<p>The number of elements is a constant integer value; elementtype may
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1049be any integral or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1050
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1051<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1052
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1053<table class="layout">
1054 <tr class="layout">
1055 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1056 <tt>&lt;4 x i32&gt;</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1057 <tt>&lt;8 x float&gt;</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1058 <tt>&lt;2 x i64&gt;</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1059 </td>
1060 <td class="left">
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1061 Packed vector of 4 32-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1062 Packed vector of 8 floating-point values.<br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1063 Packed vector of 2 64-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1064 </td>
1065 </tr>
1066</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1067</div>
1068
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1069<!-- _______________________________________________________________________ -->
1070<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1071<div class="doc_text">
1072
1073<h5>Overview:</h5>
1074
1075<p>Opaque types are used to represent unknown types in the system. This
1076corresponds (for example) to the C notion of a foward declared structure type.
1077In LLVM, opaque types can eventually be resolved to any type (not just a
1078structure type).</p>
1079
1080<h5>Syntax:</h5>
1081
1082<pre>
1083 opaque
1084</pre>
1085
1086<h5>Examples:</h5>
1087
1088<table class="layout">
1089 <tr class="layout">
1090 <td class="left">
1091 <tt>opaque</tt>
1092 </td>
1093 <td class="left">
1094 An opaque type.<br/>
1095 </td>
1096 </tr>
1097</table>
1098</div>
1099
1100
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1101<!-- *********************************************************************** -->
1102<div class="doc_section"> <a name="constants">Constants</a> </div>
1103<!-- *********************************************************************** -->
1104
1105<div class="doc_text">
1106
1107<p>LLVM has several different basic types of constants. This section describes
1108them all and their syntax.</p>
1109
1110</div>
1111
1112<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1113<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1114
1115<div class="doc_text">
1116
1117<dl>
1118 <dt><b>Boolean constants</b></dt>
1119
1120 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1121 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1122 </dd>
1123
1124 <dt><b>Integer constants</b></dt>
1125
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1126 <dd>Standard integers (such as '4') are constants of the <a
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1127 href="#t_integer">integer</a> type. Negative numbers may be used with
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1128 integer types.
1129 </dd>
1130
1131 <dt><b>Floating point constants</b></dt>
1132
1133 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1134 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1135 notation (see below). Floating point constants must have a <a
1136 href="#t_floating">floating point</a> type. </dd>
1137
1138 <dt><b>Null pointer constants</b></dt>
1139
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1140 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1141 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1142
1143</dl>
1144
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1145<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1146of floating point constants. For example, the form '<tt>double
11470x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
11484.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1149(and the only time that they are generated by the disassembler) is when a
1150floating point constant must be emitted but it cannot be represented as a
1151decimal floating point number. For example, NaN's, infinities, and other
1152special values are represented in their IEEE hexadecimal format so that
1153assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1154
1155</div>
1156
1157<!-- ======================================================================= -->
1158<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1159</div>
1160
1161<div class="doc_text">
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1162<p>Aggregate constants arise from aggregation of simple constants
1163and smaller aggregate constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1164
1165<dl>
1166 <dt><b>Structure constants</b></dt>
1167
1168 <dd>Structure constants are represented with notation similar to structure
1169 type definitions (a comma separated list of elements, surrounded by braces
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1170 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* %G }</tt>",
1171 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]1172 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1173 types of elements must match those specified by the type.
1174 </dd>
1175
1176 <dt><b>Array constants</b></dt>
1177
1178 <dd>Array constants are represented with notation similar to array type
1179 definitions (a comma separated list of elements, surrounded by square brackets
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1180 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1181 constants must have <a href="#t_array">array type</a>, and the number and
1182 types of elements must match those specified by the type.
1183 </dd>
1184
1185 <dt><b>Packed constants</b></dt>
1186
1187 <dd>Packed constants are represented with notation similar to packed type
1188 definitions (a comma separated list of elements, surrounded by
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1189 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32 42,
1190 i32 11, i32 74, i32 100 &gt;</tt>". Packed constants must have <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1191 href="#t_packed">packed type</a>, and the number and types of elements must
1192 match those specified by the type.
1193 </dd>
1194
1195 <dt><b>Zero initialization</b></dt>
1196
1197 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1198 value to zero of <em>any</em> type, including scalar and aggregate types.
1199 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]1200 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1201 initializers.
1202 </dd>
1203</dl>
1204
1205</div>
1206
1207<!-- ======================================================================= -->
1208<div class="doc_subsection">
1209 <a name="globalconstants">Global Variable and Function Addresses</a>
1210</div>
1211
1212<div class="doc_text">
1213
1214<p>The addresses of <a href="#globalvars">global variables</a> and <a
1215href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1216constants. These constants are explicitly referenced when the <a
1217href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1218href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1219file:</p>
1220
1221<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1222 %X = global i32 17
1223 %Y = global i32 42
1224 %Z = global [2 x i32*] [ i32* %X, i32* %Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1225</pre>
1226
1227</div>
1228
1229<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1230<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1231<div class="doc_text">
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1232 <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]1233 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1234 a constant is permitted.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1235
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1236 <p>Undefined values indicate to the compiler that the program is well defined
1237 no matter what value is used, giving the compiler more freedom to optimize.
1238 </p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1239</div>
1240
1241<!-- ======================================================================= -->
1242<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1243</div>
1244
1245<div class="doc_text">
1246
1247<p>Constant expressions are used to allow expressions involving other constants
1248to be used as constants. Constant expressions may be of any <a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1249href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1250that does not have side effects (e.g. load and call are not supported). The
1251following is the syntax for constant expressions:</p>
1252
1253<dl>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1254 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1255 <dd>Truncate a constant to another type. The bit size of CST must be larger
1256 than the bit size of TYPE. Both types must be integral.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1257
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1258 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1259 <dd>Zero extend a constant to another type. The bit size of CST must be
1260 smaller or equal to the bit size of TYPE. Both types must be integral.</dd>
1261
1262 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1263 <dd>Sign extend a constant to another type. The bit size of CST must be
1264 smaller or equal to the bit size of TYPE. Both types must be integral.</dd>
1265
1266 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1267 <dd>Truncate a floating point constant to another floating point type. The
1268 size of CST must be larger than the size of TYPE. Both types must be
1269 floating point.</dd>
1270
1271 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1272 <dd>Floating point extend a constant to another type. The size of CST must be
1273 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1274
1275 <dt><b><tt>fp2uint ( CST to TYPE )</tt></b></dt>
1276 <dd>Convert a floating point constant to the corresponding unsigned integer
1277 constant. TYPE must be an integer type. CST must be floating point. If the
1278 value won't fit in the integer type, the results are undefined.</dd>
1279
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1280 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1281 <dd>Convert a floating point constant to the corresponding signed integer
1282 constant. TYPE must be an integer type. CST must be floating point. If the
1283 value won't fit in the integer type, the results are undefined.</dd>
1284
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1285 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1286 <dd>Convert an unsigned integer constant to the corresponding floating point
1287 constant. TYPE must be floating point. CST must be of integer type. If the
1288 value won't fit in the floating point type, the results are undefined.</dd>
1289
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1290 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1291 <dd>Convert a signed integer constant to the corresponding floating point
1292 constant. TYPE must be floating point. CST must be of integer type. If the
1293 value won't fit in the floating point type, the results are undefined.</dd>
1294
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]1295 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1296 <dd>Convert a pointer typed constant to the corresponding integer constant
1297 TYPE must be an integer type. CST must be of pointer type. The CST value is
1298 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1299
1300 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1301 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1302 pointer type. CST must be of integer type. The CST value is zero extended,
1303 truncated, or unchanged to make it fit in a pointer size. This one is
1304 <i>really</i> dangerous!</dd>
1305
1306 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1307 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1308 identical (same number of bits). The conversion is done as if the CST value
1309 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]1310 with this operator, just the type. This can be used for conversion of
1311 packed types to any other type, as long as they have the same bit width. For
1312 pointers it is only valid to cast to another pointer type.
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1313 </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1314
1315 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1316
1317 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1318 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1319 instruction, the index list may have zero or more indexes, which are required
1320 to make sense for the type of "CSTPTR".</dd>
1321
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1322 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1323
1324 <dd>Perform the <a href="#i_select">select operation</a> on
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1325 constants.</dd>
1326
1327 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1328 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1329
1330 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1331 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1332
1333 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1334
1335 <dd>Perform the <a href="#i_extractelement">extractelement
1336 operation</a> on constants.
1337
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1338 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1339
1340 <dd>Perform the <a href="#i_insertelement">insertelement
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1341 operation</a> on constants.</dd>
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1342
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1343
1344 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1345
1346 <dd>Perform the <a href="#i_shufflevector">shufflevector
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1347 operation</a> on constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1348
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1349 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1350
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1351 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1352 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1353 binary</a> operations. The constraints on operands are the same as those for
1354 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1355 values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1356</dl>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1357</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]1358
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1359<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1360<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1361<!-- *********************************************************************** -->
1362
1363<!-- ======================================================================= -->
1364<div class="doc_subsection">
1365<a name="inlineasm">Inline Assembler Expressions</a>
1366</div>
1367
1368<div class="doc_text">
1369
1370<p>
1371LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1372Module-Level Inline Assembly</a>) through the use of a special value. This
1373value represents the inline assembler as a string (containing the instructions
1374to emit), a list of operand constraints (stored as a string), and a flag that
1375indicates whether or not the inline asm expression has side effects. An example
1376inline assembler expression is:
1377</p>
1378
1379<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1380 i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1381</pre>
1382
1383<p>
1384Inline assembler expressions may <b>only</b> be used as the callee operand of
1385a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1386</p>
1387
1388<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1389 %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]1390</pre>
1391
1392<p>
1393Inline asms with side effects not visible in the constraint list must be marked
1394as having side effects. This is done through the use of the
1395'<tt>sideeffect</tt>' keyword, like so:
1396</p>
1397
1398<pre>
1399 call void asm sideeffect "eieio", ""()
1400</pre>
1401
1402<p>TODO: The format of the asm and constraints string still need to be
1403documented here. Constraints on what can be done (e.g. duplication, moving, etc
1404need to be documented).
1405</p>
1406
1407</div>
1408
1409<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1410<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1411<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1412
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1413<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1414
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1415<p>The LLVM instruction set consists of several different
1416classifications of instructions: <a href="#terminators">terminator
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1417instructions</a>, <a href="#binaryops">binary instructions</a>,
1418<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1419 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1420instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1421
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1422</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1423
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1424<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1425<div class="doc_subsection"> <a name="terminators">Terminator
1426Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1427
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1428<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1429
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1430<p>As mentioned <a href="#functionstructure">previously</a>, every
1431basic block in a program ends with a "Terminator" instruction, which
1432indicates which block should be executed after the current block is
1433finished. These terminator instructions typically yield a '<tt>void</tt>'
1434value: they produce control flow, not values (the one exception being
1435the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1436<p>There are six different terminator instructions: the '<a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1437 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1438instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1439the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1440 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1441 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1442
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1443</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1444
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1445<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1446<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1447Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1448<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1449<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1450<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]1451 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1452</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1453<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1454<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1455value) from a function back to the caller.</p>
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]1456<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1457returns a value and then causes control flow, and one that just causes
1458control flow to occur.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1459<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1460<p>The '<tt>ret</tt>' instruction may return any '<a
1461 href="#t_firstclass">first class</a>' type. Notice that a function is
1462not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
1463instruction inside of the function that returns a value that does not
1464match the return type of the function.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1465<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1466<p>When the '<tt>ret</tt>' instruction is executed, control flow
1467returns back to the calling function's context. If the caller is a "<a
John Criswellfa081872004-06-25 15:16:57 +0000[diff] [blame]1468 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1469the instruction after the call. If the caller was an "<a
1470 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1471at the beginning of the "normal" destination block. If the instruction
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1472returns a value, that value shall set the call or invoke instruction's
1473return value.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1474<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1475<pre> ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1476 ret void <i>; Return from a void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1477</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1478</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1479<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1480<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1481<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1482<h5>Syntax:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1483<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]1484</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1485<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1486<p>The '<tt>br</tt>' instruction is used to cause control flow to
1487transfer to a different basic block in the current function. There are
1488two forms of this instruction, corresponding to a conditional branch
1489and an unconditional branch.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1490<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1491<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1492single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1493unconditional form of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>'
1494value as a target.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1495<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1496<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1497argument is evaluated. If the value is <tt>true</tt>, control flows
1498to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1499control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1500<h5>Example:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1501<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]1502 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]1503</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1504<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1505<div class="doc_subsubsection">
1506 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1507</div>
1508
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1509<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1510<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1511
1512<pre>
1513 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1514</pre>
1515
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1516<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1517
1518<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1519several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1520instruction, allowing a branch to occur to one of many possible
1521destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1522
1523
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1524<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1525
1526<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1527comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1528an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1529table is not allowed to contain duplicate constant entries.</p>
1530
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1531<h5>Semantics:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1532
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1533<p>The <tt>switch</tt> instruction specifies a table of values and
1534destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1535table is searched for the given value. If the value is found, control flow is
1536transfered to the corresponding destination; otherwise, control flow is
1537transfered to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1538
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1539<h5>Implementation:</h5>
1540
1541<p>Depending on properties of the target machine and the particular
1542<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1543ways. For example, it could be generated as a series of chained conditional
1544branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1545
1546<h5>Example:</h5>
1547
1548<pre>
1549 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1550 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1551 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1552
1553 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1554 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1555
1556 <i>; Implement a jump table:</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1557 switch i32 %val, label %otherwise [ i32 0, label %onzero
1558 i32 1, label %onone
1559 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1560</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1561</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1562
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1563<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1564<div class="doc_subsubsection">
1565 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1566</div>
1567
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1568<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1569
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1570<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1571
1572<pre>
1573 &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]1574 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1575</pre>
1576
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1577<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1578
1579<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1580function, with the possibility of control flow transfer to either the
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1581'<tt>normal</tt>' label or the
1582'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1583"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1584"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1585href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
1586continued at the dynamically nearest "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1587
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1588<h5>Arguments:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1589
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1590<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1591
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1592<ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1593 <li>
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1594 The optional "cconv" marker indicates which <a href="callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1595 convention</a> the call should use. If none is specified, the call defaults
1596 to using C calling conventions.
1597 </li>
1598 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1599 function value being invoked. In most cases, this is a direct function
1600 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1601 an arbitrary pointer to function value.
1602 </li>
1603
1604 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1605 function to be invoked. </li>
1606
1607 <li>'<tt>function args</tt>': argument list whose types match the function
1608 signature argument types. If the function signature indicates the function
1609 accepts a variable number of arguments, the extra arguments can be
1610 specified. </li>
1611
1612 <li>'<tt>normal label</tt>': the label reached when the called function
1613 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1614
1615 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1616 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1617
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1618</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1619
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1620<h5>Semantics:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1621
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1622<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1623href="#i_call">call</a></tt>' instruction in most regards. The primary
1624difference is that it establishes an association with a label, which is used by
1625the runtime library to unwind the stack.</p>
1626
1627<p>This instruction is used in languages with destructors to ensure that proper
1628cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1629exception. Additionally, this is important for implementation of
1630'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1631
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1632<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1633<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1634 %retval = invoke i32 %Test(i32 15) to label %Continue
1635 unwind label %TestCleanup <i>; {i32}:retval set</i>
1636 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Test(i32 15) to label %Continue
1637 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1638</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1639</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1640
1641
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1642<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1643
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1644<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1645Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1646
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1647<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1648
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1649<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1650<pre>
1651 unwind
1652</pre>
1653
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1654<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1655
1656<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
1657at the first callee in the dynamic call stack which used an <a
1658href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
1659primarily used to implement exception handling.</p>
1660
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1661<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1662
1663<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
1664immediately halt. The dynamic call stack is then searched for the first <a
1665href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
1666execution continues at the "exceptional" destination block specified by the
1667<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
1668dynamic call chain, undefined behavior results.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1669</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1670
1671<!-- _______________________________________________________________________ -->
1672
1673<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
1674Instruction</a> </div>
1675
1676<div class="doc_text">
1677
1678<h5>Syntax:</h5>
1679<pre>
1680 unreachable
1681</pre>
1682
1683<h5>Overview:</h5>
1684
1685<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
1686instruction is used to inform the optimizer that a particular portion of the
1687code is not reachable. This can be used to indicate that the code after a
1688no-return function cannot be reached, and other facts.</p>
1689
1690<h5>Semantics:</h5>
1691
1692<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
1693</div>
1694
1695
1696
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1697<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1698<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1699<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1700<p>Binary operators are used to do most of the computation in a
1701program. They require two operands, execute an operation on them, and
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1702produce a single value. The operands might represent
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1703multiple data, as is the case with the <a href="#t_packed">packed</a> data type.
1704The result value of a binary operator is not
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1705necessarily the same type as its operands.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1706<p>There are several different binary operators:</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1707</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1708<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1709<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
1710Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1711<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1712<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1713<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]1714</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1715<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1716<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1717<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1718<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1719 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
1720 This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1721Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1722<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1723<p>The value produced is the integer or floating point sum of the two
1724operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1725<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1726<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]1727</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1728</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1729<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1730<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
1731Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1732<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1733<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1734<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]1735</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1736<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1737<p>The '<tt>sub</tt>' instruction returns the difference of its two
1738operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1739<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
1740instruction present in most other intermediate representations.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1741<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1742<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1743 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1744values.
1745This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1746Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1747<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1748<p>The value produced is the integer or floating point difference of
1749the two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1750<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1751<pre> &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
1752 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1753</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1754</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1755<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1756<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
1757Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1758<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1759<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1760<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]1761</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1762<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1763<p>The '<tt>mul</tt>' instruction returns the product of its two
1764operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1765<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1766<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1767 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1768values.
1769This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1770Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1771<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1772<p>The value produced is the integer or floating point product of the
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1773two operands.</p>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1774<p>Because the operands are the same width, the result of an integer
1775multiplication is the same whether the operands should be deemed unsigned or
1776signed.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1777<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1778<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]1779</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1780</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1781<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1782<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
1783</a></div>
1784<div class="doc_text">
1785<h5>Syntax:</h5>
1786<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1787</pre>
1788<h5>Overview:</h5>
1789<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
1790operands.</p>
1791<h5>Arguments:</h5>
1792<p>The two arguments to the '<tt>udiv</tt>' instruction must be
1793<a href="#t_integer">integer</a> values. Both arguments must have identical
1794types. This instruction can also take <a href="#t_packed">packed</a> versions
1795of the values in which case the elements must be integers.</p>
1796<h5>Semantics:</h5>
1797<p>The value produced is the unsigned integer quotient of the two operands. This
1798instruction always performs an unsigned division operation, regardless of
1799whether the arguments are unsigned or not.</p>
1800<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1801<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]1802</pre>
1803</div>
1804<!-- _______________________________________________________________________ -->
1805<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
1806</a> </div>
1807<div class="doc_text">
1808<h5>Syntax:</h5>
1809<pre> &lt;result&gt; = sdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1810</pre>
1811<h5>Overview:</h5>
1812<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
1813operands.</p>
1814<h5>Arguments:</h5>
1815<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
1816<a href="#t_integer">integer</a> values. Both arguments must have identical
1817types. This instruction can also take <a href="#t_packed">packed</a> versions
1818of the values in which case the elements must be integers.</p>
1819<h5>Semantics:</h5>
1820<p>The value produced is the signed integer quotient of the two operands. This
1821instruction always performs a signed division operation, regardless of whether
1822the arguments are signed or not.</p>
1823<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1824<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]1825</pre>
1826</div>
1827<!-- _______________________________________________________________________ -->
1828<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1829Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1830<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1831<h5>Syntax:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1832<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]1833</pre>
1834<h5>Overview:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1835<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1836operands.</p>
1837<h5>Arguments:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1838<p>The two arguments to the '<tt>div</tt>' instruction must be
1839<a href="#t_floating">floating point</a> values. Both arguments must have
1840identical types. This instruction can also take <a href="#t_packed">packed</a>
1841versions of the values in which case the elements must be floating point.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1842<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1843<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1844<h5>Example:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1845<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]1846</pre>
1847</div>
1848<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1849<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
1850</div>
1851<div class="doc_text">
1852<h5>Syntax:</h5>
1853<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1854</pre>
1855<h5>Overview:</h5>
1856<p>The '<tt>urem</tt>' instruction returns the remainder from the
1857unsigned division of its two arguments.</p>
1858<h5>Arguments:</h5>
1859<p>The two arguments to the '<tt>urem</tt>' instruction must be
1860<a href="#t_integer">integer</a> values. Both arguments must have identical
1861types.</p>
1862<h5>Semantics:</h5>
1863<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
1864This instruction always performs an unsigned division to get the remainder,
1865regardless of whether the arguments are unsigned or not.</p>
1866<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1867<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]1868</pre>
1869
1870</div>
1871<!-- _______________________________________________________________________ -->
1872<div class="doc_subsubsection"> <a name="i_srem">'<tt>srem</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1873Instruction</a> </div>
1874<div class="doc_text">
1875<h5>Syntax:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1876<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]1877</pre>
1878<h5>Overview:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1879<p>The '<tt>srem</tt>' instruction returns the remainder from the
1880signed division of its two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1881<h5>Arguments:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1882<p>The two arguments to the '<tt>srem</tt>' instruction must be
1883<a href="#t_integer">integer</a> values. Both arguments must have identical
1884types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1885<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1886<p>This instruction returns the <i>remainder</i> of a division (where the result
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1887has the same sign as the divisor), not the <i>modulus</i> (where the
1888result has the same sign as the dividend) of a value. For more
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1889information about the difference, see <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1890 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
1891Math Forum</a>.</p>
1892<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1893<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]1894</pre>
1895
1896</div>
1897<!-- _______________________________________________________________________ -->
1898<div class="doc_subsubsection"> <a name="i_frem">'<tt>frem</tt>'
1899Instruction</a> </div>
1900<div class="doc_text">
1901<h5>Syntax:</h5>
1902<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1903</pre>
1904<h5>Overview:</h5>
1905<p>The '<tt>frem</tt>' instruction returns the remainder from the
1906division of its two operands.</p>
1907<h5>Arguments:</h5>
1908<p>The two arguments to the '<tt>frem</tt>' instruction must be
1909<a href="#t_floating">floating point</a> values. Both arguments must have
1910identical types.</p>
1911<h5>Semantics:</h5>
1912<p>This instruction returns the <i>remainder</i> of a division.</p>
1913<h5>Example:</h5>
1914<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]1915</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1916</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]1917
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1918<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1919<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
1920Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1921<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1922<p>Bitwise binary operators are used to do various forms of
1923bit-twiddling in a program. They are generally very efficient
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1924instructions and can commonly be strength reduced from other
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1925instructions. They require two operands, execute an operation on them,
1926and produce a single value. The resulting value of the bitwise binary
1927operators is always the same type as its first operand.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1928</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1929<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1930<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
1931Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1932<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1933<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1934<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]1935</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1936<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1937<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
1938its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1939<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1940<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1941 href="#t_integral">integral</a> values. Both arguments must have
1942identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1943<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1944<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1945<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1946<div style="align: center">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1947<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1948 <tbody>
1949 <tr>
1950 <td>In0</td>
1951 <td>In1</td>
1952 <td>Out</td>
1953 </tr>
1954 <tr>
1955 <td>0</td>
1956 <td>0</td>
1957 <td>0</td>
1958 </tr>
1959 <tr>
1960 <td>0</td>
1961 <td>1</td>
1962 <td>0</td>
1963 </tr>
1964 <tr>
1965 <td>1</td>
1966 <td>0</td>
1967 <td>0</td>
1968 </tr>
1969 <tr>
1970 <td>1</td>
1971 <td>1</td>
1972 <td>1</td>
1973 </tr>
1974 </tbody>
1975</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1976</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1977<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1978<pre> &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
1979 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
1980 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1981</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1982</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1983<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1984<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1985<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1986<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1987<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]1988</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1989<h5>Overview:</h5>
1990<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
1991or of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1992<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1993<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1994 href="#t_integral">integral</a> values. Both arguments must have
1995identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1996<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1997<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1998<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1999<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2000<table border="1" cellspacing="0" cellpadding="4">
2001 <tbody>
2002 <tr>
2003 <td>In0</td>
2004 <td>In1</td>
2005 <td>Out</td>
2006 </tr>
2007 <tr>
2008 <td>0</td>
2009 <td>0</td>
2010 <td>0</td>
2011 </tr>
2012 <tr>
2013 <td>0</td>
2014 <td>1</td>
2015 <td>1</td>
2016 </tr>
2017 <tr>
2018 <td>1</td>
2019 <td>0</td>
2020 <td>1</td>
2021 </tr>
2022 <tr>
2023 <td>1</td>
2024 <td>1</td>
2025 <td>1</td>
2026 </tr>
2027 </tbody>
2028</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2029</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2030<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2031<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2032 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2033 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2034</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2035</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2036<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2037<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2038Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2039<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2040<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2041<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]2042</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2043<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2044<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2045or of its two operands. The <tt>xor</tt> is used to implement the
2046"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2047<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2048<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2049 href="#t_integral">integral</a> values. Both arguments must have
2050identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2051<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2052<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2053<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2054<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2055<table border="1" cellspacing="0" cellpadding="4">
2056 <tbody>
2057 <tr>
2058 <td>In0</td>
2059 <td>In1</td>
2060 <td>Out</td>
2061 </tr>
2062 <tr>
2063 <td>0</td>
2064 <td>0</td>
2065 <td>0</td>
2066 </tr>
2067 <tr>
2068 <td>0</td>
2069 <td>1</td>
2070 <td>1</td>
2071 </tr>
2072 <tr>
2073 <td>1</td>
2074 <td>0</td>
2075 <td>1</td>
2076 </tr>
2077 <tr>
2078 <td>1</td>
2079 <td>1</td>
2080 <td>0</td>
2081 </tr>
2082 </tbody>
2083</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2084</div>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2085<p> </p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2086<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2087<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2088 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2089 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2090 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2091</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2092</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2093<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2094<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2095Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2096<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2097<h5>Syntax:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2098<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]2099</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2100<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2101<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2102the left a specified number of bits.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2103<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2104<p>The first argument to the '<tt>shl</tt>' instruction must be an <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2105 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]2106type.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2107<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2108<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]2109<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2110<pre> &lt;result&gt; = shl i32 4, i8 %var <i>; yields {i32}:result = 4 &lt;&lt; %var</i>
2111 &lt;result&gt; = shl i32 4, i8 2 <i>; yields {i32}:result = 16</i>
2112 &lt;result&gt; = shl i32 1, i8 10 <i>; yields {i32}:result = 1024</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2113</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2114</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2115<!-- _______________________________________________________________________ -->
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2116<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2117Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2118<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2119<h5>Syntax:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2120<pre> &lt;result&gt; = 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]2121</pre>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2122
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2123<h5>Overview:</h5>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2124<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
2125operand shifted to the right a specified number of bits.</p>
2126
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2127<h5>Arguments:</h5>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2128<p>The first argument to the '<tt>lshr</tt>' instruction must be an <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2129 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]2130
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2131<h5>Semantics:</h5>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]2132<p>This instruction always performs a logical shift right operation. The
2133<tt>var2</tt> most significant bits will be filled with zero bits after the
2134shift.</p>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2135
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2136<h5>Example:</h5>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2137<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2138 &lt;result&gt; = lshr i32 4, i8 1 <i>; yields {i32}:result = 2</i>
2139 &lt;result&gt; = lshr i32 4, i8 2 <i>; yields {i32}:result = 1</i>
2140 &lt;result&gt; = lshr i8 4, i8 3 <i>; yields {i8 }:result = 0</i>
2141 &lt;result&gt; = lshr i8 -2, i8 1 <i>; yields {i8 }:result = 0x7FFFFFFF </i>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2142</pre>
2143</div>
2144
2145<!-- ======================================================================= -->
2146<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2147Instruction</a> </div>
2148<div class="doc_text">
2149
2150<h5>Syntax:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2151<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]2152</pre>
2153
2154<h5>Overview:</h5>
2155<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
2156operand shifted to the right a specified number of bits.</p>
2157
2158<h5>Arguments:</h5>
2159<p>The first argument to the '<tt>ashr</tt>' instruction must be an
2160<a href="#t_integer">integer</a> type. The second argument must be an
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2161'<tt>i8</tt>' type.</p>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2162
2163<h5>Semantics:</h5>
2164<p>This instruction always performs an arithmetic shift right operation,
2165regardless of whether the arguments are signed or not. The <tt>var2</tt> most
2166significant bits will be filled with the sign bit of <tt>var1</tt>.</p>
2167
2168<h5>Example:</h5>
2169<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2170 &lt;result&gt; = ashr i32 4, i8 1 <i>; yields {i32}:result = 2</i>
2171 &lt;result&gt; = ashr i32 4, i8 2 <i>; yields {i32}:result = 1</i>
2172 &lt;result&gt; = ashr i8 4, i8 3 <i>; yields {i8}:result = 0</i>
2173 &lt;result&gt; = ashr i8 -2, i8 1 <i>; yields {i8 }:result = -1</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2174</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2175</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2176
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2177<!-- ======================================================================= -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2178<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2179 <a name="vectorops">Vector Operations</a>
2180</div>
2181
2182<div class="doc_text">
2183
2184<p>LLVM supports several instructions to represent vector operations in a
2185target-independent manner. This instructions cover the element-access and
2186vector-specific operations needed to process vectors effectively. While LLVM
2187does directly support these vector operations, many sophisticated algorithms
2188will want to use target-specific intrinsics to take full advantage of a specific
2189target.</p>
2190
2191</div>
2192
2193<!-- _______________________________________________________________________ -->
2194<div class="doc_subsubsection">
2195 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2196</div>
2197
2198<div class="doc_text">
2199
2200<h5>Syntax:</h5>
2201
2202<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2203 &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]2204</pre>
2205
2206<h5>Overview:</h5>
2207
2208<p>
2209The '<tt>extractelement</tt>' instruction extracts a single scalar
2210element from a packed vector at a specified index.
2211</p>
2212
2213
2214<h5>Arguments:</h5>
2215
2216<p>
2217The first operand of an '<tt>extractelement</tt>' instruction is a
2218value of <a href="#t_packed">packed</a> type. The second operand is
2219an index indicating the position from which to extract the element.
2220The index may be a variable.</p>
2221
2222<h5>Semantics:</h5>
2223
2224<p>
2225The result is a scalar of the same type as the element type of
2226<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2227<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2228results are undefined.
2229</p>
2230
2231<h5>Example:</h5>
2232
2233<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2234 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2235</pre>
2236</div>
2237
2238
2239<!-- _______________________________________________________________________ -->
2240<div class="doc_subsubsection">
2241 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2242</div>
2243
2244<div class="doc_text">
2245
2246<h5>Syntax:</h5>
2247
2248<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2249 &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]2250</pre>
2251
2252<h5>Overview:</h5>
2253
2254<p>
2255The '<tt>insertelement</tt>' instruction inserts a scalar
2256element into a packed vector at a specified index.
2257</p>
2258
2259
2260<h5>Arguments:</h5>
2261
2262<p>
2263The first operand of an '<tt>insertelement</tt>' instruction is a
2264value of <a href="#t_packed">packed</a> type. The second operand is a
2265scalar value whose type must equal the element type of the first
2266operand. The third operand is an index indicating the position at
2267which to insert the value. The index may be a variable.</p>
2268
2269<h5>Semantics:</h5>
2270
2271<p>
2272The result is a packed vector of the same type as <tt>val</tt>. Its
2273element values are those of <tt>val</tt> except at position
2274<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2275exceeds the length of <tt>val</tt>, the results are undefined.
2276</p>
2277
2278<h5>Example:</h5>
2279
2280<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2281 %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]2282</pre>
2283</div>
2284
2285<!-- _______________________________________________________________________ -->
2286<div class="doc_subsubsection">
2287 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2288</div>
2289
2290<div class="doc_text">
2291
2292<h5>Syntax:</h5>
2293
2294<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2295 &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]2296</pre>
2297
2298<h5>Overview:</h5>
2299
2300<p>
2301The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2302from two input vectors, returning a vector of the same type.
2303</p>
2304
2305<h5>Arguments:</h5>
2306
2307<p>
2308The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2309with types that match each other and types that match the result of the
2310instruction. The third argument is a shuffle mask, which has the same number
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2311of elements as the other vector type, but whose element type is always 'i32'.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2312</p>
2313
2314<p>
2315The shuffle mask operand is required to be a constant vector with either
2316constant integer or undef values.
2317</p>
2318
2319<h5>Semantics:</h5>
2320
2321<p>
2322The elements of the two input vectors are numbered from left to right across
2323both of the vectors. The shuffle mask operand specifies, for each element of
2324the result vector, which element of the two input registers the result element
2325gets. The element selector may be undef (meaning "don't care") and the second
2326operand may be undef if performing a shuffle from only one vector.
2327</p>
2328
2329<h5>Example:</h5>
2330
2331<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2332 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
2333 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
2334 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2335 &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]2336</pre>
2337</div>
2338
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]2339
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2340<!-- ======================================================================= -->
2341<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2342 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2343</div>
2344
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2345<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2346
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2347<p>A key design point of an SSA-based representation is how it
2348represents memory. In LLVM, no memory locations are in SSA form, which
2349makes things very simple. This section describes how to read, write,
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2350allocate, and free memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2351
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2352</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2353
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2354<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2355<div class="doc_subsubsection">
2356 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2357</div>
2358
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2359<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2360
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2361<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2362
2363<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2364 &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]2365</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2366
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2367<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2368
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2369<p>The '<tt>malloc</tt>' instruction allocates memory from the system
2370heap and returns a pointer to it.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2371
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2372<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2373
2374<p>The '<tt>malloc</tt>' instruction allocates
2375<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswell6e4ca612004-02-24 16:13:56 +0000[diff] [blame]2376bytes of memory from the operating system and returns a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2377appropriate type to the program. If "NumElements" is specified, it is the
2378number of elements allocated. If an alignment is specified, the value result
2379of the allocation is guaranteed to be aligned to at least that boundary. If
2380not specified, or if zero, the target can choose to align the allocation on any
2381convenient boundary.</p>
2382
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2383<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2384
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2385<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2386
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2387<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
2388a pointer is returned.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2389
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2390<h5>Example:</h5>
2391
2392<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2393 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2394
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2395 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
2396 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
2397 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
2398 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
2399 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2400</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2401</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2402
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2403<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2404<div class="doc_subsubsection">
2405 <a name="i_free">'<tt>free</tt>' Instruction</a>
2406</div>
2407
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2408<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2409
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2410<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2411
2412<pre>
2413 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2414</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2415
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2416<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2417
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2418<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2419memory heap to be reallocated in the future.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2420
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2421<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2422
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2423<p>'<tt>value</tt>' shall be a pointer value that points to a value
2424that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
2425instruction.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2426
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2427<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2428
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2429<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2430after this instruction executes.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2431
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2432<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2433
2434<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2435 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
2436 free [4 x i8]* %array
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2437</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2438</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2439
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2440<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2441<div class="doc_subsubsection">
2442 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
2443</div>
2444
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2445<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2446
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2447<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2448
2449<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2450 &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]2451</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2452
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2453<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2454
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2455<p>The '<tt>alloca</tt>' instruction allocates memory on the current
2456stack frame of the procedure that is live until the current function
2457returns to its caller.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2458
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2459<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2460
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2461<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2462bytes of memory on the runtime stack, returning a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2463appropriate type to the program. If "NumElements" is specified, it is the
2464number of elements allocated. If an alignment is specified, the value result
2465of the allocation is guaranteed to be aligned to at least that boundary. If
2466not specified, or if zero, the target can choose to align the allocation on any
2467convenient boundary.</p>
2468
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2469<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2470
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2471<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2472
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2473<p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2474memory is automatically released when the function returns. The '<tt>alloca</tt>'
2475instruction is commonly used to represent automatic variables that must
2476have an address available. When the function returns (either with the <tt><a
John Criswelldae2e932005-05-12 16:55:34 +0000[diff] [blame]2477 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]2478instructions), the memory is reclaimed.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2479
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2480<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2481
2482<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2483 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
2484 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
2485 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
2486 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2487</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2488</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2489
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2490<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2491<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
2492Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2493<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2494<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2495<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]2496<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2497<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2498<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2499<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2500address from which to load. The pointer must point to a <a
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]2501 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2502marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2503the number or order of execution of this <tt>load</tt> with other
2504volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
2505instructions. </p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2506<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2507<p>The location of memory pointed to is loaded.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2508<h5>Examples:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2509<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2510 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2511 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2512 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2513</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2514</div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2515<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2516<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
2517Instruction</a> </div>
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]2518<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2519<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2520<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]2521 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]2522</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2523<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2524<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2525<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2526<p>There are two arguments to the '<tt>store</tt>' instruction: a value
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2527to 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]2528operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2529operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2530optimizer is not allowed to modify the number or order of execution of
2531this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
2532 href="#i_store">store</a></tt> instructions.</p>
2533<h5>Semantics:</h5>
2534<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
2535at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2536<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2537<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2538 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2539 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2540 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2541</pre>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2542</div>
2543
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2544<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2545<div class="doc_subsubsection">
2546 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
2547</div>
2548
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2549<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2550<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2551<pre>
2552 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
2553</pre>
2554
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2555<h5>Overview:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2556
2557<p>
2558The '<tt>getelementptr</tt>' instruction is used to get the address of a
2559subelement of an aggregate data structure.</p>
2560
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2561<h5>Arguments:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2562
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2563<p>This instruction takes a list of integer operands that indicate what
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2564elements of the aggregate object to index to. The actual types of the arguments
2565provided depend on the type of the first pointer argument. The
2566'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2567levels 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]2568structure, only <tt>i32</tt> integer constants are allowed. When indexing
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2569into an array or pointer, only integers of 32 or 64 bits are allowed, and will
2570be sign extended to 64-bit values.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2571
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2572<p>For example, let's consider a C code fragment and how it gets
2573compiled to LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2574
2575<pre>
2576 struct RT {
2577 char A;
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2578 i32 B[10][20];
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2579 char C;
2580 };
2581 struct ST {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2582 i32 X;
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2583 double Y;
2584 struct RT Z;
2585 };
2586
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2587 define i32 *foo(struct ST *s) {
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2588 return &amp;s[1].Z.B[5][13];
2589 }
2590</pre>
2591
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2592<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2593
2594<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2595 %RT = type { i8 , [10 x [20 x i32]], i8 }
2596 %ST = type { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2597
Brian Gaeke7283e7c2004-07-02 21:08:14 +0000[diff] [blame]2598 implementation
2599
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2600 define i32* %foo(%ST* %s) {
Brian Gaeke7283e7c2004-07-02 21:08:14 +0000[diff] [blame]2601 entry:
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2602 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
2603 ret i32* %reg
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2604 }
2605</pre>
2606
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2607<h5>Semantics:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2608
2609<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2610on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2611and <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]2612<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]2613to 64-bits. <a href="#t_struct">Structure</a> types, require <tt>i32</tt>
Reid Spencer42ddd842006-12-03 16:53:48 +0000[diff] [blame]2614<b>constants</b>.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2615
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2616<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]2617type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2618}</tt>' type, a structure. The second index indexes into the third element of
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2619the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
2620i8 }</tt>' type, another structure. The third index indexes into the second
2621element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2622array. The two dimensions of the array are subscripted into, yielding an
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2623'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
2624to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2625
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2626<p>Note that it is perfectly legal to index partially through a
2627structure, returning a pointer to an inner element. Because of this,
2628the LLVM code for the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2629
2630<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2631 define i32* %foo(%ST* %s) {
2632 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
2633 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
2634 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
2635 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
2636 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
2637 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2638 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2639</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2640
2641<p>Note that it is undefined to access an array out of bounds: array and
2642pointer indexes must always be within the defined bounds of the array type.
2643The one exception for this rules is zero length arrays. These arrays are
2644defined to be accessible as variable length arrays, which requires access
2645beyond the zero'th element.</p>
2646
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2647<p>The getelementptr instruction is often confusing. For some more insight
2648into how it works, see <a href="GetElementPtr.html">the getelementptr
2649FAQ</a>.</p>
2650
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2651<h5>Example:</h5>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2652
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2653<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2654 <i>; yields [12 x i8]*:aptr</i>
2655 %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2656</pre>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2657</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2658
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2659<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]2660<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2661</div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2662<div class="doc_text">
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]2663<p>The instructions in this category are the conversion instructions (casting)
2664which all take a single operand and a type. They perform various bit conversions
2665on the operand.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2666</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2667
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2668<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2669<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2670 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
2671</div>
2672<div class="doc_text">
2673
2674<h5>Syntax:</h5>
2675<pre>
2676 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2677</pre>
2678
2679<h5>Overview:</h5>
2680<p>
2681The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
2682</p>
2683
2684<h5>Arguments:</h5>
2685<p>
2686The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
2687be an <a href="#t_integer">integer</a> type, and a type that specifies the size
2688and type of the result, which must be an <a href="#t_integral">integral</a>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2689type. The bit size of <tt>value</tt> must be larger than the bit size of
2690<tt>ty2</tt>. Equal sized types are not allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2691
2692<h5>Semantics:</h5>
2693<p>
2694The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2695and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
2696larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
2697It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2698
2699<h5>Example:</h5>
2700<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2701 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2702 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
2703 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2704</pre>
2705</div>
2706
2707<!-- _______________________________________________________________________ -->
2708<div class="doc_subsubsection">
2709 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
2710</div>
2711<div class="doc_text">
2712
2713<h5>Syntax:</h5>
2714<pre>
2715 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2716</pre>
2717
2718<h5>Overview:</h5>
2719<p>The '<tt>zext</tt>' instruction zero extends its operand to type
2720<tt>ty2</tt>.</p>
2721
2722
2723<h5>Arguments:</h5>
2724<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
2725<a href="#t_integral">integral</a> type, and a type to cast it to, which must
2726also be of <a href="#t_integral">integral</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2727<tt>value</tt> must be smaller than the bit size of the destination type,
2728<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2729
2730<h5>Semantics:</h5>
2731<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
2732bits until it reaches the size of the destination type, <tt>ty2</tt>. When the
2733the operand and the type are the same size, no bit filling is done and the
2734cast is considered a <i>no-op cast</i> because no bits change (only the type
2735changes).</p>
2736
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame^]2737<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]2738
2739<h5>Example:</h5>
2740<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2741 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2742 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2743</pre>
2744</div>
2745
2746<!-- _______________________________________________________________________ -->
2747<div class="doc_subsubsection">
2748 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
2749</div>
2750<div class="doc_text">
2751
2752<h5>Syntax:</h5>
2753<pre>
2754 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2755</pre>
2756
2757<h5>Overview:</h5>
2758<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
2759
2760<h5>Arguments:</h5>
2761<p>
2762The '<tt>sext</tt>' instruction takes a value to cast, which must be of
2763<a href="#t_integral">integral</a> type, and a type to cast it to, which must
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2764also be of <a href="#t_integral">integral</a> type. The bit size of the
2765<tt>value</tt> must be smaller than the bit size of the destination type,
2766<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2767
2768<h5>Semantics:</h5>
2769<p>
2770The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
2771bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
2772the type <tt>ty2</tt>. When the the operand and the type are the same size,
2773no bit filling is done and the cast is considered a <i>no-op cast</i> because
2774no bits change (only the type changes).</p>
2775
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2776<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]2777
2778<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2779<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2780 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2781 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2782</pre>
2783</div>
2784
2785<!-- _______________________________________________________________________ -->
2786<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]2787 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
2788</div>
2789
2790<div class="doc_text">
2791
2792<h5>Syntax:</h5>
2793
2794<pre>
2795 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2796</pre>
2797
2798<h5>Overview:</h5>
2799<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
2800<tt>ty2</tt>.</p>
2801
2802
2803<h5>Arguments:</h5>
2804<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
2805 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
2806cast it to. The size of <tt>value</tt> must be larger than the size of
2807<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
2808<i>no-op cast</i>.</p>
2809
2810<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2811<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
2812<a href="#t_floating">floating point</a> type to a smaller
2813<a href="#t_floating">floating point</a> type. If the value cannot fit within
2814the destination type, <tt>ty2</tt>, then the results are undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]2815
2816<h5>Example:</h5>
2817<pre>
2818 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
2819 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
2820</pre>
2821</div>
2822
2823<!-- _______________________________________________________________________ -->
2824<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2825 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
2826</div>
2827<div class="doc_text">
2828
2829<h5>Syntax:</h5>
2830<pre>
2831 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2832</pre>
2833
2834<h5>Overview:</h5>
2835<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
2836floating point value.</p>
2837
2838<h5>Arguments:</h5>
2839<p>The '<tt>fpext</tt>' instruction takes a
2840<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2841and a <a href="#t_floating">floating point</a> type to cast it to. The source
2842type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2843
2844<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2845<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
2846<a href="t_floating">floating point</a> type to a larger
2847<a href="t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
2848used to make a <i>no-op cast</i> because it always changes bits. Use
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2849<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]2850
2851<h5>Example:</h5>
2852<pre>
2853 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
2854 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
2855</pre>
2856</div>
2857
2858<!-- _______________________________________________________________________ -->
2859<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2860 <a name="i_fp2uint">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2861</div>
2862<div class="doc_text">
2863
2864<h5>Syntax:</h5>
2865<pre>
2866 &lt;result&gt; = fp2uint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2867</pre>
2868
2869<h5>Overview:</h5>
2870<p>The '<tt>fp2uint</tt>' converts a floating point <tt>value</tt> to its
2871unsigned integer equivalent of type <tt>ty2</tt>.
2872</p>
2873
2874<h5>Arguments:</h5>
2875<p>The '<tt>fp2uint</tt>' instruction takes a value to cast, which must be a
2876<a href="#t_floating">floating point</a> value, and a type to cast it to, which
2877must be an <a href="#t_integral">integral</a> type.</p>
2878
2879<h5>Semantics:</h5>
2880<p> The '<tt>fp2uint</tt>' instruction converts its
2881<a href="#t_floating">floating point</a> operand into the nearest (rounding
2882towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
2883the results are undefined.</p>
2884
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2885<p>When converting to i1, the conversion is done as a comparison against
2886zero. If the <tt>value</tt> was zero, the i1 result will be <tt>false</tt>.
2887If 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]2888
2889<h5>Example:</h5>
2890<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2891 %X = fp2uint double 123.0 to i32 <i>; yields i32:123</i>
2892 %Y = fp2uint float 1.0E+300 to i1 <i>; yields i1:true</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2893 %X = fp2uint float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2894</pre>
2895</div>
2896
2897<!-- _______________________________________________________________________ -->
2898<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2899 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2900</div>
2901<div class="doc_text">
2902
2903<h5>Syntax:</h5>
2904<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2905 &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]2906</pre>
2907
2908<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2909<p>The '<tt>fptosi</tt>' instruction converts
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2910<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]2911</p>
2912
2913
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2914<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2915<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]2916<a href="#t_floating">floating point</a> value, and a type to cast it to, which
2917must also be an <a href="#t_integral">integral</a> type.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2918
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2919<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2920<p>The '<tt>fptosi</tt>' instruction converts its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2921<a href="#t_floating">floating point</a> operand into the nearest (rounding
2922towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
2923the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2924
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2925<p>When converting to i1, the conversion is done as a comparison against
2926zero. If the <tt>value</tt> was zero, the i1 result will be <tt>false</tt>.
2927If 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]2928
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2929<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2930<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2931 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
2932 %Y = fptosi float 1.0E-247 to i1 <i>; yields i1:true</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2933 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2934</pre>
2935</div>
2936
2937<!-- _______________________________________________________________________ -->
2938<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2939 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2940</div>
2941<div class="doc_text">
2942
2943<h5>Syntax:</h5>
2944<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2945 &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]2946</pre>
2947
2948<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2949<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2950integer and converts that value to the <tt>ty2</tt> type.</p>
2951
2952
2953<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2954<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be an
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2955<a href="#t_integral">integral</a> value, and a type to cast it to, which must
2956be a <a href="#t_floating">floating point</a> type.</p>
2957
2958<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2959<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2960integer quantity and converts it to the corresponding floating point value. If
2961the value cannot fit in the floating point value, the results are undefined.</p>
2962
2963
2964<h5>Example:</h5>
2965<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2966 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
2967 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2968</pre>
2969</div>
2970
2971<!-- _______________________________________________________________________ -->
2972<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2973 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2974</div>
2975<div class="doc_text">
2976
2977<h5>Syntax:</h5>
2978<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2979 &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]2980</pre>
2981
2982<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2983<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2984integer and converts that value to the <tt>ty2</tt> type.</p>
2985
2986<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2987<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be an
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2988<a href="#t_integral">integral</a> value, and a type to cast it to, which must be
2989a <a href="#t_floating">floating point</a> type.</p>
2990
2991<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2992<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2993integer quantity and converts it to the corresponding floating point value. If
2994the value cannot fit in the floating point value, the results are undefined.</p>
2995
2996<h5>Example:</h5>
2997<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2998 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
2999 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3000</pre>
3001</div>
3002
3003<!-- _______________________________________________________________________ -->
3004<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3005 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3006</div>
3007<div class="doc_text">
3008
3009<h5>Syntax:</h5>
3010<pre>
3011 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3012</pre>
3013
3014<h5>Overview:</h5>
3015<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3016the integer type <tt>ty2</tt>.</p>
3017
3018<h5>Arguments:</h5>
3019<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
3020must be a <a href="t_pointer">pointer</a> value, and a type to cast it to
3021<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
3022
3023<h5>Semantics:</h5>
3024<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3025<tt>ty2</tt> by interpreting the pointer value as an integer and either
3026truncating or zero extending that value to the size of the integer type. If
3027<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3028<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
3029are the same size, then nothing is done (<i>no-op cast</i>).</p>
3030
3031<h5>Example:</h5>
3032<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3033 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit</i>
3034 %Y = ptrtoint i32* %x to i64 <i>; yields zero extend on 32-bit</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3035</pre>
3036</div>
3037
3038<!-- _______________________________________________________________________ -->
3039<div class="doc_subsubsection">
3040 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3041</div>
3042<div class="doc_text">
3043
3044<h5>Syntax:</h5>
3045<pre>
3046 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3047</pre>
3048
3049<h5>Overview:</h5>
3050<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3051a pointer type, <tt>ty2</tt>.</p>
3052
3053<h5>Arguments:</h5>
3054<p>The '<tt>inttoptr</tt>' instruction takes an <a href="i_integer">integer</a>
3055value to cast, and a type to cast it to, which must be a
3056<a href="#t_pointer">pointer</a> type. </tt>
3057
3058<h5>Semantics:</h5>
3059<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3060<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3061the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3062size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3063the size of a pointer then a zero extension is done. If they are the same size,
3064nothing is done (<i>no-op cast</i>).</p>
3065
3066<h5>Example:</h5>
3067<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3068 %X = inttoptr i32 255 to i32* <i>; yields zero extend on 64-bit</i>
3069 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit </i>
3070 %Y = inttoptr i16 0 to i32* <i>; yields zero extend on 32-bit</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3071</pre>
3072</div>
3073
3074<!-- _______________________________________________________________________ -->
3075<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3076 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3077</div>
3078<div class="doc_text">
3079
3080<h5>Syntax:</h5>
3081<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3082 &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]3083</pre>
3084
3085<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3086<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3087<tt>ty2</tt> without changing any bits.</p>
3088
3089<h5>Arguments:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3090<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3091a first class value, and a type to cast it to, which must also be a <a
3092 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
Reid Spencer19b569f2007-01-09 20:08:58 +0000[diff] [blame]3093and the destination type, <tt>ty2</tt>, must be identical. If the source
3094type is a pointer, the destination type must also be a pointer.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3095
3096<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3097<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3098<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3099this conversion. The conversion is done as if the <tt>value</tt> had been
3100stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3101converted to other pointer types with this instruction. To convert pointers to
3102other types, use the <a href="#i_inttoptr">inttoptr</a> or
3103<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3104
3105<h5>Example:</h5>
3106<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3107 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
3108 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
3109 %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3110</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3111</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3112
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3113<!-- ======================================================================= -->
3114<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3115<div class="doc_text">
3116<p>The instructions in this category are the "miscellaneous"
3117instructions, which defy better classification.</p>
3118</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3119
3120<!-- _______________________________________________________________________ -->
3121<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3122</div>
3123<div class="doc_text">
3124<h5>Syntax:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3125<pre> &lt;result&gt; = icmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt;
3126<i>; yields {i1}:result</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3127</pre>
3128<h5>Overview:</h5>
3129<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
3130of its two integer operands.</p>
3131<h5>Arguments:</h5>
3132<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
3133the condition code which indicates the kind of comparison to perform. It is not
3134a value, just a keyword. The possibilities for the condition code are:
3135<ol>
3136 <li><tt>eq</tt>: equal</li>
3137 <li><tt>ne</tt>: not equal </li>
3138 <li><tt>ugt</tt>: unsigned greater than</li>
3139 <li><tt>uge</tt>: unsigned greater or equal</li>
3140 <li><tt>ult</tt>: unsigned less than</li>
3141 <li><tt>ule</tt>: unsigned less or equal</li>
3142 <li><tt>sgt</tt>: signed greater than</li>
3143 <li><tt>sge</tt>: signed greater or equal</li>
3144 <li><tt>slt</tt>: signed less than</li>
3145 <li><tt>sle</tt>: signed less or equal</li>
3146</ol>
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3147<p>The remaining two arguments must be <a href="#t_integral">integral</a> or
3148<a href="#t_pointer">pointer</a> typed. They must also be identical types.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3149<h5>Semantics:</h5>
3150<p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3151the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3152yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3153<ol>
3154 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3155 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3156 </li>
3157 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3158 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3159 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3160 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3161 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3162 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3163 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3164 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3165 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3166 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3167 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3168 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3169 <li><tt>sge</tt>: interprets the operands as signed values and yields
3170 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3171 <li><tt>slt</tt>: interprets the operands as signed values and yields
3172 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3173 <li><tt>sle</tt>: interprets the operands as signed values and yields
3174 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3175 </li>
3176</ol>
3177<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
3178values are treated as integers and then compared.</p>
3179<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]3180the vector are compared in turn and the predicate must hold for all
3181elements.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3182
3183<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3184<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3185 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3186 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3187 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3188 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3189 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3190</pre>
3191</div>
3192
3193<!-- _______________________________________________________________________ -->
3194<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3195</div>
3196<div class="doc_text">
3197<h5>Syntax:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3198<pre> &lt;result&gt; = fcmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt;
3199<i>; yields {i1}:result</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3200</pre>
3201<h5>Overview:</h5>
3202<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3203of its floating point operands.</p>
3204<h5>Arguments:</h5>
3205<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
3206the condition code which indicates the kind of comparison to perform. It is not
3207a value, just a keyword. The possibilities for the condition code are:
3208<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3209 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3210 <li><tt>oeq</tt>: ordered and equal</li>
3211 <li><tt>ogt</tt>: ordered and greater than </li>
3212 <li><tt>oge</tt>: ordered and greater than or equal</li>
3213 <li><tt>olt</tt>: ordered and less than </li>
3214 <li><tt>ole</tt>: ordered and less than or equal</li>
3215 <li><tt>one</tt>: ordered and not equal</li>
3216 <li><tt>ord</tt>: ordered (no nans)</li>
3217 <li><tt>ueq</tt>: unordered or equal</li>
3218 <li><tt>ugt</tt>: unordered or greater than </li>
3219 <li><tt>uge</tt>: unordered or greater than or equal</li>
3220 <li><tt>ult</tt>: unordered or less than </li>
3221 <li><tt>ule</tt>: unordered or less than or equal</li>
3222 <li><tt>une</tt>: unordered or not equal</li>
3223 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3224 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3225</ol>
Reid Spencer93a49852006-12-06 07:08:07 +0000[diff] [blame]3226<p>In the preceding, <i>ordered</i> means that neither operand is a QNAN while
3227<i>unordered</i> means that either operand may be a QNAN.</p>
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3228<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be
3229<a href="#t_floating">floating point</a> typed. They must have identical
3230types.</p>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3231<p>In the foregoing, <i>ordered</i> means that neither operand is a QNAN and
3232<i>unordered</i> means that either operand is a QNAN.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3233<h5>Semantics:</h5>
3234<p>The '<tt>fcmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3235the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3236yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3237<ol>
3238 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3239 <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]3240 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3241 <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]3242 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3243 <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]3244 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3245 <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]3246 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3247 <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]3248 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3249 <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]3250 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3251 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3252 <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]3253 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3254 <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]3255 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3256 <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]3257 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3258 <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]3259 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3260 <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]3261 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3262 <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]3263 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3264 <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]3265 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3266</ol>
3267<p>If the operands are <a href="#t_packed">packed</a> typed, the elements of
3268the vector are compared in turn and the predicate must hold for all elements.
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3269</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3270
3271<h5>Example:</h5>
3272<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3273 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3274 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3275 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3276</pre>
3277</div>
3278
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3279<!-- _______________________________________________________________________ -->
3280<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
3281Instruction</a> </div>
3282<div class="doc_text">
3283<h5>Syntax:</h5>
3284<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
3285<h5>Overview:</h5>
3286<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
3287the SSA graph representing the function.</p>
3288<h5>Arguments:</h5>
3289<p>The type of the incoming values are specified with the first type
3290field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
3291as arguments, with one pair for each predecessor basic block of the
3292current block. Only values of <a href="#t_firstclass">first class</a>
3293type may be used as the value arguments to the PHI node. Only labels
3294may be used as the label arguments.</p>
3295<p>There must be no non-phi instructions between the start of a basic
3296block and the PHI instructions: i.e. PHI instructions must be first in
3297a basic block.</p>
3298<h5>Semantics:</h5>
3299<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the
3300value specified by the parameter, depending on which basic block we
3301came from in the last <a href="#terminators">terminator</a> instruction.</p>
3302<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3303<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]3304</div>
3305
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3306<!-- _______________________________________________________________________ -->
3307<div class="doc_subsubsection">
3308 <a name="i_select">'<tt>select</tt>' Instruction</a>
3309</div>
3310
3311<div class="doc_text">
3312
3313<h5>Syntax:</h5>
3314
3315<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3316 &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]3317</pre>
3318
3319<h5>Overview:</h5>
3320
3321<p>
3322The '<tt>select</tt>' instruction is used to choose one value based on a
3323condition, without branching.
3324</p>
3325
3326
3327<h5>Arguments:</h5>
3328
3329<p>
3330The '<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.
3331</p>
3332
3333<h5>Semantics:</h5>
3334
3335<p>
3336If the boolean condition evaluates to true, the instruction returns the first
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3337value argument; otherwise, it returns the second value argument.
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3338</p>
3339
3340<h5>Example:</h5>
3341
3342<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3343 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3344</pre>
3345</div>
3346
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]3347
3348<!-- _______________________________________________________________________ -->
3349<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3350 <a name="i_call">'<tt>call</tt>' Instruction</a>
3351</div>
3352
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3353<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3354
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3355<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3356<pre>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3357 &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]3358</pre>
3359
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3360<h5>Overview:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3361
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3362<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3363
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3364<h5>Arguments:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3365
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3366<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3367
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3368<ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3369 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3370 <p>The optional "tail" marker indicates whether the callee function accesses
3371 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3372 function call is eligible for tail call optimization. Note that calls may
3373 be marked "tail" even if they do not occur before a <a
3374 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3375 </li>
3376 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3377 <p>The optional "cconv" marker indicates which <a href="callingconv">calling
3378 convention</a> the call should use. If none is specified, the call defaults
3379 to using C calling conventions.
3380 </li>
3381 <li>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3382 <p>'<tt>ty</tt>': shall be the signature of the pointer to function value
3383 being invoked. The argument types must match the types implied by this
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3384 signature. This type can be omitted if the function is not varargs and
3385 if the function type does not return a pointer to a function.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3386 </li>
3387 <li>
3388 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
3389 be invoked. In most cases, this is a direct function invocation, but
3390 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3391 to function value.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3392 </li>
3393 <li>
3394 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencera7e302a2005-05-01 22:22:57 +0000[diff] [blame]3395 function signature argument types. All arguments must be of
3396 <a href="#t_firstclass">first class</a> type. If the function signature
3397 indicates the function accepts a variable number of arguments, the extra
3398 arguments can be specified.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3399 </li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3400</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3401
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3402<h5>Semantics:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3403
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3404<p>The '<tt>call</tt>' instruction is used to cause control flow to
3405transfer to a specified function, with its incoming arguments bound to
3406the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
3407instruction in the called function, control flow continues with the
3408instruction after the function call, and the return value of the
3409function is bound to the result argument. This is a simpler case of
3410the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3411
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3412<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3413
3414<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3415 %retval = call i32 %test(i32 %argc)
3416 call i32(i8 *, ...) *%printf(i8 * %msg, i32 12, i8 42);
3417 %X = tail call i32 %foo()
3418 %Y = tail call <a href="#callingconv">fastcc</a> i32 %foo()
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3419</pre>
3420
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3421</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3422
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3423<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3424<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3425 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3426</div>
3427
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3428<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3429
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3430<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3431
3432<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3433 &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]3434</pre>
3435
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3436<h5>Overview:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3437
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3438<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3439the "variable argument" area of a function call. It is used to implement the
3440<tt>va_arg</tt> macro in C.</p>
3441
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3442<h5>Arguments:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3443
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3444<p>This instruction takes a <tt>va_list*</tt> value and the type of
3445the argument. It returns a value of the specified argument type and
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]3446increments the <tt>va_list</tt> to point to the next argument. Again, the
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3447actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3448
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3449<h5>Semantics:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3450
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3451<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
3452type from the specified <tt>va_list</tt> and causes the
3453<tt>va_list</tt> to point to the next argument. For more information,
3454see the variable argument handling <a href="#int_varargs">Intrinsic
3455Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3456
3457<p>It is legal for this instruction to be called in a function which does not
3458take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3459function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3460
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3461<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3462href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3463argument.</p>
3464
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3465<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3466
3467<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
3468
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3469</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3470
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3471<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3472<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
3473<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3474
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3475<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3476
3477<p>LLVM supports the notion of an "intrinsic function". These functions have
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3478well known names and semantics and are required to follow certain
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3479restrictions. Overall, these instructions represent an extension mechanism for
3480the LLVM language that does not require changing all of the transformations in
3481LLVM to add to the language (or the bytecode reader/writer, the parser,
3482etc...).</p>
3483
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3484<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
3485prefix is reserved in LLVM for intrinsic names; thus, functions may not be named
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3486this. Intrinsic functions must always be external functions: you cannot define
3487the body of intrinsic functions. Intrinsic functions may only be used in call
3488or invoke instructions: it is illegal to take the address of an intrinsic
3489function. Additionally, because intrinsic functions are part of the LLVM
3490language, it is required that they all be documented here if any are added.</p>
3491
3492
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3493<p>To learn how to add an intrinsic function, please see the <a
Chris Lattner590cff32005-05-11 03:35:57 +0000[diff] [blame]3494href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3495</p>
3496
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3497</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3498
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3499<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3500<div class="doc_subsection">
3501 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
3502</div>
3503
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3504<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3505
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3506<p>Variable argument support is defined in LLVM with the <a
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3507 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3508intrinsic functions. These functions are related to the similarly
3509named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3510
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3511<p>All of these functions operate on arguments that use a
3512target-specific value type "<tt>va_list</tt>". The LLVM assembly
3513language reference manual does not define what this type is, so all
3514transformations should be prepared to handle intrinsics with any type
3515used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3516
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]3517<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]3518instruction and the variable argument handling intrinsic functions are
3519used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3520
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3521<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3522define i32 %test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3523 ; Initialize variable argument processing
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3524 %ap = alloca i8 *
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3525 %ap2 = bitcast i8** %ap to i8*
3526 call void %<a href="#i_va_start">llvm.va_start</a>(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3527
3528 ; Read a single integer argument
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3529 %tmp = va_arg i8 ** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3530
3531 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3532 %aq = alloca i8 *
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3533 %aq2 = bitcast i8** %aq to i8*
3534 call void %<a href="#i_va_copy">llvm.va_copy</a>(i8 *%aq2, i8* %ap2)
3535 call void %<a href="#i_va_end">llvm.va_end</a>(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3536
3537 ; Stop processing of arguments.
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3538 call void %<a href="#i_va_end">llvm.va_end</a>(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3539 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3540}
3541</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3542</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3543
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3544<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3545<div class="doc_subsubsection">
3546 <a name="i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
3547</div>
3548
3549
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3550<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3551<h5>Syntax:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3552<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3553<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3554<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
3555<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
3556href="#i_va_arg">va_arg</a></tt>.</p>
3557
3558<h5>Arguments:</h5>
3559
3560<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
3561
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3562<h5>Semantics:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3563
3564<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
3565macro available in C. In a target-dependent way, it initializes the
3566<tt>va_list</tt> element the argument points to, so that the next call to
3567<tt>va_arg</tt> will produce the first variable argument passed to the function.
3568Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
3569last argument of the function, the compiler can figure that out.</p>
3570
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3571</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3572
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3573<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3574<div class="doc_subsubsection">
3575 <a name="i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
3576</div>
3577
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3578<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3579<h5>Syntax:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3580<pre> declare void %llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3581<h5>Overview:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3582
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3583<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>&lt;arglist&gt;</tt>
3584which has been initialized previously with <tt><a href="#i_va_start">llvm.va_start</a></tt>
3585or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3586
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3587<h5>Arguments:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3588
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3589<p>The argument is a <tt>va_list</tt> to destroy.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3590
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3591<h5>Semantics:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3592
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3593<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]3594macro available in C. In a target-dependent way, it destroys the <tt>va_list</tt>.
3595Calls to <a href="#i_va_start"><tt>llvm.va_start</tt></a> and <a
3596 href="#i_va_copy"><tt>llvm.va_copy</tt></a> must be matched exactly
3597with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3598
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3599</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3600
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3601<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3602<div class="doc_subsubsection">
3603 <a name="i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
3604</div>
3605
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3606<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3607
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3608<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3609
3610<pre>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3611 declare void %llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3612</pre>
3613
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3614<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3615
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3616<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position from
3617the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3618
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3619<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3620
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3621<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]3622The 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]3623
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3624
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3625<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3626
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3627<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt> macro
3628available in C. In a target-dependent way, it copies the source
3629<tt>va_list</tt> element into the destination list. This intrinsic is necessary
3630because 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]3631arbitrarily complex and require memory allocation, for example.</p>
3632
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3633</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3634
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3635<!-- ======================================================================= -->
3636<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3637 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
3638</div>
3639
3640<div class="doc_text">
3641
3642<p>
3643LLVM support for <a href="GarbageCollection.html">Accurate Garbage
3644Collection</a> requires the implementation and generation of these intrinsics.
3645These intrinsics allow identification of <a href="#i_gcroot">GC roots on the
3646stack</a>, as well as garbage collector implementations that require <a
3647href="#i_gcread">read</a> and <a href="#i_gcwrite">write</a> barriers.
3648Front-ends for type-safe garbage collected languages should generate these
3649intrinsics to make use of the LLVM garbage collectors. For more details, see <a
3650href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
3651</p>
3652</div>
3653
3654<!-- _______________________________________________________________________ -->
3655<div class="doc_subsubsection">
3656 <a name="i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
3657</div>
3658
3659<div class="doc_text">
3660
3661<h5>Syntax:</h5>
3662
3663<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]3664 declare void %llvm.gcroot(&lt;ty&gt;** %ptrloc, &lt;ty2&gt;* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3665</pre>
3666
3667<h5>Overview:</h5>
3668
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]3669<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]3670the code generator, and allows some metadata to be associated with it.</p>
3671
3672<h5>Arguments:</h5>
3673
3674<p>The first argument specifies the address of a stack object that contains the
3675root pointer. The second pointer (which must be either a constant or a global
3676value address) contains the meta-data to be associated with the root.</p>
3677
3678<h5>Semantics:</h5>
3679
3680<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
3681location. At compile-time, the code generator generates information to allow
3682the runtime to find the pointer at GC safe points.
3683</p>
3684
3685</div>
3686
3687
3688<!-- _______________________________________________________________________ -->
3689<div class="doc_subsubsection">
3690 <a name="i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
3691</div>
3692
3693<div class="doc_text">
3694
3695<h5>Syntax:</h5>
3696
3697<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3698 declare i8 * %llvm.gcread(i8 * %ObjPtr, i8 ** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3699</pre>
3700
3701<h5>Overview:</h5>
3702
3703<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
3704locations, allowing garbage collector implementations that require read
3705barriers.</p>
3706
3707<h5>Arguments:</h5>
3708
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3709<p>The second argument is the address to read from, which should be an address
3710allocated from the garbage collector. The first object is a pointer to the
3711start of the referenced object, if needed by the language runtime (otherwise
3712null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3713
3714<h5>Semantics:</h5>
3715
3716<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
3717instruction, but may be replaced with substantially more complex code by the
3718garbage collector runtime, as needed.</p>
3719
3720</div>
3721
3722
3723<!-- _______________________________________________________________________ -->
3724<div class="doc_subsubsection">
3725 <a name="i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
3726</div>
3727
3728<div class="doc_text">
3729
3730<h5>Syntax:</h5>
3731
3732<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3733 declare void %llvm.gcwrite(i8 * %P1, i8 * %Obj, i8 ** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3734</pre>
3735
3736<h5>Overview:</h5>
3737
3738<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
3739locations, allowing garbage collector implementations that require write
3740barriers (such as generational or reference counting collectors).</p>
3741
3742<h5>Arguments:</h5>
3743
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3744<p>The first argument is the reference to store, the second is the start of the
3745object to store it to, and the third is the address of the field of Obj to
3746store to. If the runtime does not require a pointer to the object, Obj may be
3747null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3748
3749<h5>Semantics:</h5>
3750
3751<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
3752instruction, but may be replaced with substantially more complex code by the
3753garbage collector runtime, as needed.</p>
3754
3755</div>
3756
3757
3758
3759<!-- ======================================================================= -->
3760<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3761 <a name="int_codegen">Code Generator Intrinsics</a>
3762</div>
3763
3764<div class="doc_text">
3765<p>
3766These intrinsics are provided by LLVM to expose special features that may only
3767be implemented with code generator support.
3768</p>
3769
3770</div>
3771
3772<!-- _______________________________________________________________________ -->
3773<div class="doc_subsubsection">
3774 <a name="i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
3775</div>
3776
3777<div class="doc_text">
3778
3779<h5>Syntax:</h5>
3780<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3781 declare i8 *%llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3782</pre>
3783
3784<h5>Overview:</h5>
3785
3786<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]3787The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
3788target-specific value indicating the return address of the current function
3789or one of its callers.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3790</p>
3791
3792<h5>Arguments:</h5>
3793
3794<p>
3795The argument to this intrinsic indicates which function to return the address
3796for. Zero indicates the calling function, one indicates its caller, etc. The
3797argument is <b>required</b> to be a constant integer value.
3798</p>
3799
3800<h5>Semantics:</h5>
3801
3802<p>
3803The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
3804the return address of the specified call frame, or zero if it cannot be
3805identified. The value returned by this intrinsic is likely to be incorrect or 0
3806for arguments other than zero, so it should only be used for debugging purposes.
3807</p>
3808
3809<p>
3810Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]3811aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3812source-language caller.
3813</p>
3814</div>
3815
3816
3817<!-- _______________________________________________________________________ -->
3818<div class="doc_subsubsection">
3819 <a name="i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
3820</div>
3821
3822<div class="doc_text">
3823
3824<h5>Syntax:</h5>
3825<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3826 declare i8 *%llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3827</pre>
3828
3829<h5>Overview:</h5>
3830
3831<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]3832The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
3833target-specific frame pointer value for the specified stack frame.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3834</p>
3835
3836<h5>Arguments:</h5>
3837
3838<p>
3839The argument to this intrinsic indicates which function to return the frame
3840pointer for. Zero indicates the calling function, one indicates its caller,
3841etc. The argument is <b>required</b> to be a constant integer value.
3842</p>
3843
3844<h5>Semantics:</h5>
3845
3846<p>
3847The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
3848the frame address of the specified call frame, or zero if it cannot be
3849identified. The value returned by this intrinsic is likely to be incorrect or 0
3850for arguments other than zero, so it should only be used for debugging purposes.
3851</p>
3852
3853<p>
3854Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]3855aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3856source-language caller.
3857</p>
3858</div>
3859
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3860<!-- _______________________________________________________________________ -->
3861<div class="doc_subsubsection">
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]3862 <a name="i_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
3863</div>
3864
3865<div class="doc_text">
3866
3867<h5>Syntax:</h5>
3868<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3869 declare i8 *%llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]3870</pre>
3871
3872<h5>Overview:</h5>
3873
3874<p>
3875The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
3876the function stack, for use with <a href="#i_stackrestore">
3877<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
3878features like scoped automatic variable sized arrays in C99.
3879</p>
3880
3881<h5>Semantics:</h5>
3882
3883<p>
3884This intrinsic returns a opaque pointer value that can be passed to <a
3885href="#i_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
3886<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
3887<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
3888state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
3889practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
3890that were allocated after the <tt>llvm.stacksave</tt> was executed.
3891</p>
3892
3893</div>
3894
3895<!-- _______________________________________________________________________ -->
3896<div class="doc_subsubsection">
3897 <a name="i_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
3898</div>
3899
3900<div class="doc_text">
3901
3902<h5>Syntax:</h5>
3903<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3904 declare void %llvm.stackrestore(i8 * %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]3905</pre>
3906
3907<h5>Overview:</h5>
3908
3909<p>
3910The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
3911the function stack to the state it was in when the corresponding <a
3912href="#llvm.stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
3913useful for implementing language features like scoped automatic variable sized
3914arrays in C99.
3915</p>
3916
3917<h5>Semantics:</h5>
3918
3919<p>
3920See the description for <a href="#i_stacksave"><tt>llvm.stacksave</tt></a>.
3921</p>
3922
3923</div>
3924
3925
3926<!-- _______________________________________________________________________ -->
3927<div class="doc_subsubsection">
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3928 <a name="i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
3929</div>
3930
3931<div class="doc_text">
3932
3933<h5>Syntax:</h5>
3934<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3935 declare void %llvm.prefetch(i8 * &lt;address&gt;,
3936 i32 &lt;rw&gt;, i32 &lt;locality&gt;)
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3937</pre>
3938
3939<h5>Overview:</h5>
3940
3941
3942<p>
3943The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3944a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
3945no
3946effect on the behavior of the program but can change its performance
Chris Lattner2a615362005-02-28 19:47:14 +0000[diff] [blame]3947characteristics.
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3948</p>
3949
3950<h5>Arguments:</h5>
3951
3952<p>
3953<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
3954determining if the fetch should be for a read (0) or write (1), and
3955<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattneraeffb4a2005-03-07 20:31:38 +0000[diff] [blame]3956locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3957<tt>locality</tt> arguments must be constant integers.
3958</p>
3959
3960<h5>Semantics:</h5>
3961
3962<p>
3963This intrinsic does not modify the behavior of the program. In particular,
3964prefetches cannot trap and do not produce a value. On targets that support this
3965intrinsic, the prefetch can provide hints to the processor cache for better
3966performance.
3967</p>
3968
3969</div>
3970
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]3971<!-- _______________________________________________________________________ -->
3972<div class="doc_subsubsection">
3973 <a name="i_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
3974</div>
3975
3976<div class="doc_text">
3977
3978<h5>Syntax:</h5>
3979<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3980 declare void %llvm.pcmarker( i32 &lt;id&gt; )
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]3981</pre>
3982
3983<h5>Overview:</h5>
3984
3985
3986<p>
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3987The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
3988(PC) in a region of
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]3989code to simulators and other tools. The method is target specific, but it is
3990expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]3991The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnerd07c3f42005-11-15 06:07:55 +0000[diff] [blame]3992after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb3e7afd2006-03-24 07:16:10 +0000[diff] [blame]3993optimizations. The intended use is to be inserted after optimizations to allow
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3994correlations of simulation runs.
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]3995</p>
3996
3997<h5>Arguments:</h5>
3998
3999<p>
4000<tt>id</tt> is a numerical id identifying the marker.
4001</p>
4002
4003<h5>Semantics:</h5>
4004
4005<p>
4006This intrinsic does not modify the behavior of the program. Backends that do not
4007support this intrinisic may ignore it.
4008</p>
4009
4010</div>
4011
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4012<!-- _______________________________________________________________________ -->
4013<div class="doc_subsubsection">
4014 <a name="i_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
4015</div>
4016
4017<div class="doc_text">
4018
4019<h5>Syntax:</h5>
4020<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4021 declare i64 %llvm.readcyclecounter( )
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4022</pre>
4023
4024<h5>Overview:</h5>
4025
4026
4027<p>
4028The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
4029counter register (or similar low latency, high accuracy clocks) on those targets
4030that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
4031As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
4032should only be used for small timings.
4033</p>
4034
4035<h5>Semantics:</h5>
4036
4037<p>
4038When directly supported, reading the cycle counter should not modify any memory.
4039Implementations are allowed to either return a application specific value or a
4040system wide value. On backends without support, this is lowered to a constant 0.
4041</p>
4042
4043</div>
4044
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4045<!-- ======================================================================= -->
4046<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4047 <a name="int_libc">Standard C Library Intrinsics</a>
4048</div>
4049
4050<div class="doc_text">
4051<p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4052LLVM provides intrinsics for a few important standard C library functions.
4053These intrinsics allow source-language front-ends to pass information about the
4054alignment of the pointer arguments to the code generator, providing opportunity
4055for more efficient code generation.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4056</p>
4057
4058</div>
4059
4060<!-- _______________________________________________________________________ -->
4061<div class="doc_subsubsection">
4062 <a name="i_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
4063</div>
4064
4065<div class="doc_text">
4066
4067<h5>Syntax:</h5>
4068<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4069 declare void %llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4070 i32 &lt;len&gt;, i32 &lt;align&gt;)
4071 declare void %llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4072 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4073</pre>
4074
4075<h5>Overview:</h5>
4076
4077<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4078The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4079location to the destination location.
4080</p>
4081
4082<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4083Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4084intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4085</p>
4086
4087<h5>Arguments:</h5>
4088
4089<p>
4090The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4091the source. The third argument is an integer argument
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4092specifying the number of bytes to copy, and the fourth argument is the alignment
4093of the source and destination locations.
4094</p>
4095
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4096<p>
4097If 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]4098the caller guarantees that both the source and destination pointers are aligned
4099to that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4100</p>
4101
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4102<h5>Semantics:</h5>
4103
4104<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4105The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4106location to the destination location, which are not allowed to overlap. It
4107copies "len" bytes of memory over. If the argument is known to be aligned to
4108some boundary, this can be specified as the fourth argument, otherwise it should
4109be set to 0 or 1.
4110</p>
4111</div>
4112
4113
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4114<!-- _______________________________________________________________________ -->
4115<div class="doc_subsubsection">
4116 <a name="i_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
4117</div>
4118
4119<div class="doc_text">
4120
4121<h5>Syntax:</h5>
4122<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4123 declare void %llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4124 i32 &lt;len&gt;, i32 &lt;align&gt;)
4125 declare void %llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4126 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4127</pre>
4128
4129<h5>Overview:</h5>
4130
4131<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4132The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
4133location to the destination location. It is similar to the
4134'<tt>llvm.memcmp</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4135</p>
4136
4137<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4138Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
4139intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4140</p>
4141
4142<h5>Arguments:</h5>
4143
4144<p>
4145The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4146the source. The third argument is an integer argument
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4147specifying the number of bytes to copy, and the fourth argument is the alignment
4148of the source and destination locations.
4149</p>
4150
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4151<p>
4152If 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]4153the caller guarantees that the source and destination pointers are aligned to
4154that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4155</p>
4156
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4157<h5>Semantics:</h5>
4158
4159<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4160The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4161location to the destination location, which may overlap. It
4162copies "len" bytes of memory over. If the argument is known to be aligned to
4163some boundary, this can be specified as the fourth argument, otherwise it should
4164be set to 0 or 1.
4165</p>
4166</div>
4167
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4168
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4169<!-- _______________________________________________________________________ -->
4170<div class="doc_subsubsection">
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4171 <a name="i_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4172</div>
4173
4174<div class="doc_text">
4175
4176<h5>Syntax:</h5>
4177<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4178 declare void %llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
4179 i32 &lt;len&gt;, i32 &lt;align&gt;)
4180 declare void %llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
4181 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4182</pre>
4183
4184<h5>Overview:</h5>
4185
4186<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4187The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4188byte value.
4189</p>
4190
4191<p>
4192Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
4193does not return a value, and takes an extra alignment argument.
4194</p>
4195
4196<h5>Arguments:</h5>
4197
4198<p>
4199The first argument is a pointer to the destination to fill, the second is the
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4200byte value to fill it with, the third argument is an integer
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4201argument specifying the number of bytes to fill, and the fourth argument is the
4202known alignment of destination location.
4203</p>
4204
4205<p>
4206If 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]4207the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4208</p>
4209
4210<h5>Semantics:</h5>
4211
4212<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4213The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
4214the
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4215destination location. If the argument is known to be aligned to some boundary,
4216this can be specified as the fourth argument, otherwise it should be set to 0 or
42171.
4218</p>
4219</div>
4220
4221
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4222<!-- _______________________________________________________________________ -->
4223<div class="doc_subsubsection">
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4224 <a name="i_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4225</div>
4226
4227<div class="doc_text">
4228
4229<h5>Syntax:</h5>
4230<pre>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4231 declare float %llvm.sqrt.f32(float %Val)
4232 declare double %llvm.sqrt.f64(double %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4233</pre>
4234
4235<h5>Overview:</h5>
4236
4237<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4238The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4239returning the same value as the libm '<tt>sqrt</tt>' function would. Unlike
4240<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
4241negative numbers (which allows for better optimization).
4242</p>
4243
4244<h5>Arguments:</h5>
4245
4246<p>
4247The argument and return value are floating point numbers of the same type.
4248</p>
4249
4250<h5>Semantics:</h5>
4251
4252<p>
4253This function returns the sqrt of the specified operand if it is a positive
4254floating point number.
4255</p>
4256</div>
4257
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4258<!-- _______________________________________________________________________ -->
4259<div class="doc_subsubsection">
4260 <a name="i_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
4261</div>
4262
4263<div class="doc_text">
4264
4265<h5>Syntax:</h5>
4266<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4267 declare float %llvm.powi.f32(float %Val, i32 %power)
4268 declare double %llvm.powi.f64(double %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4269</pre>
4270
4271<h5>Overview:</h5>
4272
4273<p>
4274The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
4275specified (positive or negative) power. The order of evaluation of
4276multiplications is not defined.
4277</p>
4278
4279<h5>Arguments:</h5>
4280
4281<p>
4282The second argument is an integer power, and the first is a value to raise to
4283that power.
4284</p>
4285
4286<h5>Semantics:</h5>
4287
4288<p>
4289This function returns the first value raised to the second power with an
4290unspecified sequence of rounding operations.</p>
4291</div>
4292
4293
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4294<!-- ======================================================================= -->
4295<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4296 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4297</div>
4298
4299<div class="doc_text">
4300<p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4301LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4302These allow efficient code generation for some algorithms.
4303</p>
4304
4305</div>
4306
4307<!-- _______________________________________________________________________ -->
4308<div class="doc_subsubsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4309 <a name="i_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
4310</div>
4311
4312<div class="doc_text">
4313
4314<h5>Syntax:</h5>
4315<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4316 declare i16 %llvm.bswap.i16(i16 &lt;id&gt;)
4317 declare i32 %llvm.bswap.i32(i32 &lt;id&gt;)
4318 declare i64 %llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4319</pre>
4320
4321<h5>Overview:</h5>
4322
4323<p>
4324The '<tt>llvm.bwsap</tt>' family of intrinsics is used to byteswap a 16, 32 or
432564 bit quantity. These are useful for performing operations on data that is not
4326in the target's native byte order.
4327</p>
4328
4329<h5>Semantics:</h5>
4330
4331<p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4332The <tt>llvm.bswap.16</tt> intrinsic returns an i16 value that has the high
4333and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
4334intrinsic returns an i32 value that has the four bytes of the input i32
4335swapped, so that if the input bytes are numbered 0, 1, 2, 3 then the returned
4336i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i64</tt>
4337intrinsic extends this concept to 64 bits.
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4338</p>
4339
4340</div>
4341
4342<!-- _______________________________________________________________________ -->
4343<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4344 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4345</div>
4346
4347<div class="doc_text">
4348
4349<h5>Syntax:</h5>
4350<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4351 declare i8 %llvm.ctpop.i8 (i8 &lt;src&gt;)
4352 declare i16 %llvm.ctpop.i16(i16 &lt;src&gt;)
4353 declare i32 %llvm.ctpop.i32(i32 &lt;src&gt;)
4354 declare i64 %llvm.ctpop.i64(i64 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4355</pre>
4356
4357<h5>Overview:</h5>
4358
4359<p>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4360The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
4361value.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4362</p>
4363
4364<h5>Arguments:</h5>
4365
4366<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]4367The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4368integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4369</p>
4370
4371<h5>Semantics:</h5>
4372
4373<p>
4374The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
4375</p>
4376</div>
4377
4378<!-- _______________________________________________________________________ -->
4379<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]4380 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4381</div>
4382
4383<div class="doc_text">
4384
4385<h5>Syntax:</h5>
4386<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4387 declare i8 %llvm.ctlz.i8 (i8 &lt;src&gt;)
4388 declare i16 %llvm.ctlz.i16(i16 &lt;src&gt;)
4389 declare i32 %llvm.ctlz.i32(i32 &lt;src&gt;)
4390 declare i64 %llvm.ctlz.i64(i64 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4391</pre>
4392
4393<h5>Overview:</h5>
4394
4395<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4396The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
4397leading zeros in a variable.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4398</p>
4399
4400<h5>Arguments:</h5>
4401
4402<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]4403The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4404integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4405</p>
4406
4407<h5>Semantics:</h5>
4408
4409<p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4410The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
4411in 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]4412of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4413</p>
4414</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4415
4416
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4417
4418<!-- _______________________________________________________________________ -->
4419<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]4420 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4421</div>
4422
4423<div class="doc_text">
4424
4425<h5>Syntax:</h5>
4426<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4427 declare i8 %llvm.cttz.i8 (i8 &lt;src&gt;)
4428 declare i16 %llvm.cttz.i16(i16 &lt;src&gt;)
4429 declare i32 %llvm.cttz.i32(i32 &lt;src&gt;)
4430 declare i64 %llvm.cttz.i64(i64 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4431</pre>
4432
4433<h5>Overview:</h5>
4434
4435<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4436The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
4437trailing zeros.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4438</p>
4439
4440<h5>Arguments:</h5>
4441
4442<p>
4443The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4444integer type. The return type must match the argument type.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4445</p>
4446
4447<h5>Semantics:</h5>
4448
4449<p>
4450The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
4451in a variable. If the src == 0 then the result is the size in bits of the type
4452of src. For example, <tt>llvm.cttz(2) = 1</tt>.
4453</p>
4454</div>
4455
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4456<!-- ======================================================================= -->
4457<div class="doc_subsection">
4458 <a name="int_debugger">Debugger Intrinsics</a>
4459</div>
4460
4461<div class="doc_text">
4462<p>
4463The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
4464are described in the <a
4465href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
4466Debugging</a> document.
4467</p>
4468</div>
4469
4470
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4471<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4472<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]4473<address>
4474 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
4475 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
4476 <a href="http://validator.w3.org/check/referer"><img
4477 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!" /></a>
4478
4479 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]4480 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]4481 Last modified: $Date$
4482</address>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4483</body>
4484</html>