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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / c92d25d50b7267fad0d3553cd8b7f443aa02af11 / . / 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>
27 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]28 </ol>
29 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]30 <li><a href="#typesystem">Type System</a>
31 <ol>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]32 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]33 <ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]34 <li><a href="#t_classifications">Type Classifications</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]35 </ol>
36 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]37 <li><a href="#t_derived">Derived Types</a>
38 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]39 <li><a href="#t_array">Array Type</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]40 <li><a href="#t_function">Function Type</a></li>
41 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]42 <li><a href="#t_struct">Structure Type</a></li>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]43 <li><a href="#t_pstruct">Packed Structure Type</a></li>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]44 <li><a href="#t_packed">Packed Type</a></li>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]45 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]46 </ol>
47 </li>
48 </ol>
49 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]50 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]51 <ol>
52 <li><a href="#simpleconstants">Simple Constants</a>
53 <li><a href="#aggregateconstants">Aggregate Constants</a>
54 <li><a href="#globalconstants">Global Variable and Function Addresses</a>
55 <li><a href="#undefvalues">Undefined Values</a>
56 <li><a href="#constantexprs">Constant Expressions</a>
57 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]58 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]59 <li><a href="#othervalues">Other Values</a>
60 <ol>
61 <li><a href="#inlineasm">Inline Assembler Expressions</a>
62 </ol>
63 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]64 <li><a href="#instref">Instruction Reference</a>
65 <ol>
66 <li><a href="#terminators">Terminator Instructions</a>
67 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]68 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
69 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]70 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
71 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]72 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]73 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]74 </ol>
75 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]76 <li><a href="#binaryops">Binary Operations</a>
77 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]78 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
79 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
80 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]81 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
82 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
83 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]84 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
85 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
86 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]87 </ol>
88 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]89 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
90 <ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]91 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]92 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]93 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
94 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]95 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
96 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]97 </ol>
98 </li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]99 <li><a href="#vectorops">Vector Operations</a>
100 <ol>
101 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
102 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
103 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]104 </ol>
105 </li>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]106 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]107 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]108 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
109 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
110 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]111 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
112 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
113 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]114 </ol>
115 </li>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]116 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]117 <ol>
118 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
119 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
120 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
121 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
122 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]123 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
124 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
125 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
126 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]127 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
128 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]129 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]130 </ol>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]131 <li><a href="#otherops">Other Operations</a>
132 <ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]133 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
134 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]135 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]136 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]137 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]138 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]139 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]140 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]141 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]142 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]143 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]144 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]145 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
146 <ol>
147 <li><a href="#i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
148 <li><a href="#i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
149 <li><a href="#i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
150 </ol>
151 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]152 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
153 <ol>
154 <li><a href="#i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
155 <li><a href="#i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
156 <li><a href="#i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
157 </ol>
158 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]159 <li><a href="#int_codegen">Code Generator Intrinsics</a>
160 <ol>
161 <li><a href="#i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
162 <li><a href="#i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]163 <li><a href="#i_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
164 <li><a href="#i_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]165 <li><a href="#i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]166 <li><a href="#i_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]167 <li><a href="#i_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]168 </ol>
169 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]170 <li><a href="#int_libc">Standard C Library Intrinsics</a>
171 <ol>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]172 <li><a href="#i_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
173 <li><a href="#i_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
174 <li><a href="#i_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]175 <li><a href="#i_isunordered">'<tt>llvm.isunordered.*</tt>' Intrinsic</a></li>
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>
251 %x = <a href="#i_add">add</a> int 1, %x
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
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]299href="#t_void">void</a></tt>', '<tt><a href="#t_uint">uint</a></tt>', etc...),
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>
309 %result = <a href="#i_mul">mul</a> uint %X, 8
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>
315 %result = <a href="#i_shl">shl</a> uint %X, ubyte 3
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>
321 <a href="#i_add">add</a> uint %X, %X <i>; yields {uint}:%0</i>
322 <a href="#i_add">add</a> uint %0, %0 <i>; yields {uint}:%1</i>
323 %result = <a href="#i_add">add</a> uint %1, %1
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
367 href="#globalvars">constant</a> <a href="#t_array">[13 x sbyte]</a> c"hello world\0A\00" <i>; [13 x sbyte]*</i>
368
369<i>; External declaration of the puts function</i>
370<a href="#functionstructure">declare</a> int %puts(sbyte*) <i>; int(sbyte*)* </i>
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>
376int %main() { <i>; int()* </i>
377 <i>; Convert [13x sbyte]* to sbyte *...</i>
378 %cast210 = <a
379 href="#i_getelementptr">getelementptr</a> [13 x sbyte]* %.LC0, long 0, long 0 <i>; sbyte*</i>
380
381 <i>; Call puts function to write out the string to stdout...</i>
382 <a
383 href="#i_call">call</a> int %puts(sbyte* %cast210) <i>; int</i>
384 <a
385 href="#i_ret">ret</a> int 0<br>}<br></pre>
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
443 used to implement constructs in C such as "<tt>int 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
497outside of the current module. It is illegal for a function <i>declaration</i>
498to have any linkage type other than "externally visible".</a></p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]499
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]500</div>
501
502<!-- ======================================================================= -->
503<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]504 <a name="callingconv">Calling Conventions</a>
505</div>
506
507<div class="doc_text">
508
509<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
510and <a href="#i_invoke">invokes</a> can all have an optional calling convention
511specified for the call. The calling convention of any pair of dynamic
512caller/callee must match, or the behavior of the program is undefined. The
513following calling conventions are supported by LLVM, and more may be added in
514the future:</p>
515
516<dl>
517 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
518
519 <dd>This calling convention (the default if no other calling convention is
520 specified) matches the target C calling conventions. This calling convention
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]521 supports varargs function calls and tolerates some mismatch in the declared
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]522 prototype and implemented declaration of the function (as does normal C).
523 </dd>
524
Chris Lattner5710ce92006-05-19 21:15:36 +0000[diff] [blame]525 <dt><b>"<tt>csretcc</tt>" - The C struct return calling convention</b>:</dt>
526
527 <dd>This calling convention matches the target C calling conventions, except
528 that functions with this convention are required to take a pointer as their
529 first argument, and the return type of the function must be void. This is
530 used for C functions that return aggregates by-value. In this case, the
531 function has been transformed to take a pointer to the struct as the first
532 argument to the function. For targets where the ABI specifies specific
533 behavior for structure-return calls, the calling convention can be used to
534 distinguish between struct return functions and other functions that take a
535 pointer to a struct as the first argument.
536 </dd>
537
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]538 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
539
540 <dd>This calling convention attempts to make calls as fast as possible
541 (e.g. by passing things in registers). This calling convention allows the
542 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner8cdc5bc2005-05-06 23:08:23 +0000[diff] [blame]543 without having to conform to an externally specified ABI. Implementations of
544 this convention should allow arbitrary tail call optimization to be supported.
545 This calling convention does not support varargs and requires the prototype of
546 all callees to exactly match the prototype of the function definition.
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]547 </dd>
548
549 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
550
551 <dd>This calling convention attempts to make code in the caller as efficient
552 as possible under the assumption that the call is not commonly executed. As
553 such, these calls often preserve all registers so that the call does not break
554 any live ranges in the caller side. This calling convention does not support
555 varargs and requires the prototype of all callees to exactly match the
556 prototype of the function definition.
557 </dd>
558
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]559 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]560
561 <dd>Any calling convention may be specified by number, allowing
562 target-specific calling conventions to be used. Target specific calling
563 conventions start at 64.
564 </dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]565</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]566
567<p>More calling conventions can be added/defined on an as-needed basis, to
568support pascal conventions or any other well-known target-independent
569convention.</p>
570
571</div>
572
573<!-- ======================================================================= -->
574<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]575 <a name="globalvars">Global Variables</a>
576</div>
577
578<div class="doc_text">
579
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]580<p>Global variables define regions of memory allocated at compilation time
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]581instead of run-time. Global variables may optionally be initialized, may have
582an explicit section to be placed in, and may
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]583have an optional explicit alignment specified. A
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]584variable may be defined as a global "constant," which indicates that the
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]585contents of the variable will <b>never</b> be modified (enabling better
586optimization, allowing the global data to be placed in the read-only section of
587an executable, etc). Note that variables that need runtime initialization
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]588cannot be marked "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]589
590<p>
591LLVM explicitly allows <em>declarations</em> of global variables to be marked
592constant, even if the final definition of the global is not. This capability
593can be used to enable slightly better optimization of the program, but requires
594the language definition to guarantee that optimizations based on the
595'constantness' are valid for the translation units that do not include the
596definition.
597</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]598
599<p>As SSA values, global variables define pointer values that are in
600scope (i.e. they dominate) all basic blocks in the program. Global
601variables always define a pointer to their "content" type because they
602describe a region of memory, and all memory objects in LLVM are
603accessed through pointers.</p>
604
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]605<p>LLVM allows an explicit section to be specified for globals. If the target
606supports it, it will emit globals to the section specified.</p>
607
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]608<p>An explicit alignment may be specified for a global. If not present, or if
609the alignment is set to zero, the alignment of the global is set by the target
610to whatever it feels convenient. If an explicit alignment is specified, the
611global is forced to have at least that much alignment. All alignments must be
612a power of 2.</p>
613
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]614</div>
615
616
617<!-- ======================================================================= -->
618<div class="doc_subsection">
619 <a name="functionstructure">Functions</a>
620</div>
621
622<div class="doc_text">
623
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]624<p>LLVM function definitions consist of an optional <a href="#linkage">linkage
625type</a>, an optional <a href="#callingconv">calling convention</a>, a return
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]626type, a function name, a (possibly empty) argument list, an optional section,
627an optional alignment, an opening curly brace,
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]628a list of basic blocks, and a closing curly brace. LLVM function declarations
629are defined with the "<tt>declare</tt>" keyword, an optional <a
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]630href="#callingconv">calling convention</a>, a return type, a function name,
631a possibly empty list of arguments, and an optional alignment.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]632
633<p>A function definition contains a list of basic blocks, forming the CFG for
634the function. Each basic block may optionally start with a label (giving the
635basic block a symbol table entry), contains a list of instructions, and ends
636with a <a href="#terminators">terminator</a> instruction (such as a branch or
637function return).</p>
638
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]639<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]640executed on entrance to the function, and it is not allowed to have predecessor
641basic blocks (i.e. there can not be any branches to the entry block of a
642function). Because the block can have no predecessors, it also cannot have any
643<a href="#i_phi">PHI nodes</a>.</p>
644
645<p>LLVM functions are identified by their name and type signature. Hence, two
646functions with the same name but different parameter lists or return values are
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]647considered different functions, and LLVM will resolve references to each
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]648appropriately.</p>
649
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]650<p>LLVM allows an explicit section to be specified for functions. If the target
651supports it, it will emit functions to the section specified.</p>
652
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]653<p>An explicit alignment may be specified for a function. If not present, or if
654the alignment is set to zero, the alignment of the function is set by the target
655to whatever it feels convenient. If an explicit alignment is specified, the
656function is forced to have at least that much alignment. All alignments must be
657a power of 2.</p>
658
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]659</div>
660
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]661<!-- ======================================================================= -->
662<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]663 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]664</div>
665
666<div class="doc_text">
667<p>
668Modules may contain "module-level inline asm" blocks, which corresponds to the
669GCC "file scope inline asm" blocks. These blocks are internally concatenated by
670LLVM and treated as a single unit, but may be separated in the .ll file if
671desired. The syntax is very simple:
672</p>
673
674<div class="doc_code"><pre>
Chris Lattner52599e12006-01-24 00:37:20 +0000[diff] [blame]675 module asm "inline asm code goes here"
676 module asm "more can go here"
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]677</pre></div>
678
679<p>The strings can contain any character by escaping non-printable characters.
680 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
681 for the number.
682</p>
683
684<p>
685 The inline asm code is simply printed to the machine code .s file when
686 assembly code is generated.
687</p>
688</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]689
690
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]691<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]692<div class="doc_section"> <a name="typesystem">Type System</a> </div>
693<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]694
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]695<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]696
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]697<p>The LLVM type system is one of the most important features of the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]698intermediate representation. Being typed enables a number of
699optimizations to be performed on the IR directly, without having to do
700extra analyses on the side before the transformation. A strong type
701system makes it easier to read the generated code and enables novel
702analyses and transformations that are not feasible to perform on normal
703three address code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]704
705</div>
706
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]707<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]708<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]709<div class="doc_text">
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]710<p>The primitive types are the fundamental building blocks of the LLVM
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]711system. The current set of primitive types is as follows:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]712
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]713<table class="layout">
714 <tr class="layout">
715 <td class="left">
716 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]717 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]718 <tr><th>Type</th><th>Description</th></tr>
719 <tr><td><tt>void</tt></td><td>No value</td></tr>
Misha Brukmancfa87bc2005-04-22 18:02:52 +0000[diff] [blame]720 <tr><td><tt>ubyte</tt></td><td>Unsigned 8-bit value</td></tr>
721 <tr><td><tt>ushort</tt></td><td>Unsigned 16-bit value</td></tr>
722 <tr><td><tt>uint</tt></td><td>Unsigned 32-bit value</td></tr>
723 <tr><td><tt>ulong</tt></td><td>Unsigned 64-bit value</td></tr>
724 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]725 <tr><td><tt>label</tt></td><td>Branch destination</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]726 </tbody>
727 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]728 </td>
729 <td class="right">
730 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]731 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]732 <tr><th>Type</th><th>Description</th></tr>
733 <tr><td><tt>bool</tt></td><td>True or False value</td></tr>
Misha Brukmancfa87bc2005-04-22 18:02:52 +0000[diff] [blame]734 <tr><td><tt>sbyte</tt></td><td>Signed 8-bit value</td></tr>
735 <tr><td><tt>short</tt></td><td>Signed 16-bit value</td></tr>
736 <tr><td><tt>int</tt></td><td>Signed 32-bit value</td></tr>
737 <tr><td><tt>long</tt></td><td>Signed 64-bit value</td></tr>
738 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]739 </tbody>
740 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]741 </td>
742 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]743</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]744</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]745
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]746<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]747<div class="doc_subsubsection"> <a name="t_classifications">Type
748Classifications</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]749<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]750<p>These different primitive types fall into a few useful
751classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]752
753<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]754 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]755 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]756 <tr>
757 <td><a name="t_signed">signed</a></td>
758 <td><tt>sbyte, short, int, long, float, double</tt></td>
759 </tr>
760 <tr>
761 <td><a name="t_unsigned">unsigned</a></td>
762 <td><tt>ubyte, ushort, uint, ulong</tt></td>
763 </tr>
764 <tr>
765 <td><a name="t_integer">integer</a></td>
766 <td><tt>ubyte, sbyte, ushort, short, uint, int, ulong, long</tt></td>
767 </tr>
768 <tr>
769 <td><a name="t_integral">integral</a></td>
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]770 <td><tt>bool, ubyte, sbyte, ushort, short, uint, int, ulong, long</tt>
771 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]772 </tr>
773 <tr>
774 <td><a name="t_floating">floating point</a></td>
775 <td><tt>float, double</tt></td>
776 </tr>
777 <tr>
778 <td><a name="t_firstclass">first class</a></td>
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]779 <td><tt>bool, ubyte, sbyte, ushort, short, uint, int, ulong, long,<br>
780 float, double, <a href="#t_pointer">pointer</a>,
781 <a href="#t_packed">packed</a></tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]782 </tr>
783 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]784</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]785
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]786<p>The <a href="#t_firstclass">first class</a> types are perhaps the
787most important. Values of these types are the only ones which can be
788produced by instructions, passed as arguments, or used as operands to
789instructions. This means that all structures and arrays must be
790manipulated either by pointer or by component.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]791</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]792
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]793<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]794<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]795
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]796<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]797
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]798<p>The real power in LLVM comes from the derived types in the system.
799This is what allows a programmer to represent arrays, functions,
800pointers, and other useful types. Note that these derived types may be
801recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]802
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]803</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]804
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]805<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]806<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]807
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]808<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]809
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]810<h5>Overview:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]811
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]812<p>The array type is a very simple derived type that arranges elements
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]813sequentially in memory. The array type requires a size (number of
814elements) and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]815
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]816<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]817
818<pre>
819 [&lt;# elements&gt; x &lt;elementtype&gt;]
820</pre>
821
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]822<p>The number of elements is a constant integer value; elementtype may
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]823be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]824
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]825<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]826<table class="layout">
827 <tr class="layout">
828 <td class="left">
829 <tt>[40 x int ]</tt><br/>
830 <tt>[41 x int ]</tt><br/>
831 <tt>[40 x uint]</tt><br/>
832 </td>
833 <td class="left">
834 Array of 40 integer values.<br/>
835 Array of 41 integer values.<br/>
836 Array of 40 unsigned integer values.<br/>
837 </td>
838 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]839</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]840<p>Here are some examples of multidimensional arrays:</p>
841<table class="layout">
842 <tr class="layout">
843 <td class="left">
844 <tt>[3 x [4 x int]]</tt><br/>
845 <tt>[12 x [10 x float]]</tt><br/>
846 <tt>[2 x [3 x [4 x uint]]]</tt><br/>
847 </td>
848 <td class="left">
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]849 3x4 array of integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]850 12x10 array of single precision floating point values.<br/>
851 2x3x4 array of unsigned integer values.<br/>
852 </td>
853 </tr>
854</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]855
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]856<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
857length array. Normally, accesses past the end of an array are undefined in
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]858LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
859As a special case, however, zero length arrays are recognized to be variable
860length. This allows implementation of 'pascal style arrays' with the LLVM
861type "{ int, [0 x float]}", for example.</p>
862
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]863</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]864
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]865<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]866<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]867<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]868<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]869<p>The function type can be thought of as a function signature. It
870consists of a return type and a list of formal parameter types.
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]871Function types are usually used to build virtual function tables
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]872(which are structures of pointers to functions), for indirect function
873calls, and when defining a function.</p>
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]874<p>
875The return type of a function type cannot be an aggregate type.
876</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]877<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]878<pre> &lt;returntype&gt; (&lt;parameter list&gt;)<br></pre>
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]879<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]880specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]881which indicates that the function takes a variable number of arguments.
882Variable argument functions can access their arguments with the <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]883 href="#int_varargs">variable argument handling intrinsic</a> functions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]884<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]885<table class="layout">
886 <tr class="layout">
887 <td class="left">
888 <tt>int (int)</tt> <br/>
889 <tt>float (int, int *) *</tt><br/>
890 <tt>int (sbyte *, ...)</tt><br/>
891 </td>
892 <td class="left">
893 function taking an <tt>int</tt>, returning an <tt>int</tt><br/>
894 <a href="#t_pointer">Pointer</a> to a function that takes an
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]895 <tt>int</tt> and a <a href="#t_pointer">pointer</a> to <tt>int</tt>,
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]896 returning <tt>float</tt>.<br/>
897 A vararg function that takes at least one <a href="#t_pointer">pointer</a>
898 to <tt>sbyte</tt> (signed char in C), which returns an integer. This is
899 the signature for <tt>printf</tt> in LLVM.<br/>
900 </td>
901 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]902</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]903
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]904</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]905<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]906<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]907<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]908<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]909<p>The structure type is used to represent a collection of data members
910together in memory. The packing of the field types is defined to match
911the ABI of the underlying processor. The elements of a structure may
912be any type that has a size.</p>
913<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
914and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
915field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
916instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]917<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]918<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]919<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]920<table class="layout">
921 <tr class="layout">
922 <td class="left">
923 <tt>{ int, int, int }</tt><br/>
924 <tt>{ float, int (int) * }</tt><br/>
925 </td>
926 <td class="left">
927 a triple of three <tt>int</tt> values<br/>
928 A pair, where the first element is a <tt>float</tt> and the second element
929 is a <a href="#t_pointer">pointer</a> to a <a href="#t_function">function</a>
930 that takes an <tt>int</tt>, returning an <tt>int</tt>.<br/>
931 </td>
932 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]933</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]934</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]935
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]936<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]937<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
938</div>
939<div class="doc_text">
940<h5>Overview:</h5>
941<p>The packed structure type is used to represent a collection of data members
942together in memory. There is no padding between fields. Further, the alignment
943of a packed structure is 1 byte. The elements of a packed structure may
944be any type that has a size.</p>
945<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
946and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
947field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
948instruction.</p>
949<h5>Syntax:</h5>
950<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
951<h5>Examples:</h5>
952<table class="layout">
953 <tr class="layout">
954 <td class="left">
955 <tt> &lt; { int, int, int } &gt; </tt><br/>
956 <tt> &lt; { float, int (int) * } &gt; </tt><br/>
957 </td>
958 <td class="left">
959 a triple of three <tt>int</tt> values<br/>
960 A pair, where the first element is a <tt>float</tt> and the second element
961 is a <a href="#t_pointer">pointer</a> to a <a href="#t_function">function</a>
962 that takes an <tt>int</tt>, returning an <tt>int</tt>.<br/>
963 </td>
964 </tr>
965</table>
966</div>
967
968<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]969<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]970<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]971<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]972<p>As in many languages, the pointer type represents a pointer or
973reference to another object, which must live in memory.</p>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]974<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]975<pre> &lt;type&gt; *<br></pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]976<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]977<table class="layout">
978 <tr class="layout">
979 <td class="left">
980 <tt>[4x int]*</tt><br/>
981 <tt>int (int *) *</tt><br/>
982 </td>
983 <td class="left">
984 A <a href="#t_pointer">pointer</a> to <a href="#t_array">array</a> of
985 four <tt>int</tt> values<br/>
986 A <a href="#t_pointer">pointer</a> to a <a
Chris Lattnera977c482005-02-19 02:22:14 +0000[diff] [blame]987 href="#t_function">function</a> that takes an <tt>int*</tt>, returning an
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]988 <tt>int</tt>.<br/>
989 </td>
990 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]991</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]992</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]993
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]994<!-- _______________________________________________________________________ -->
995<div class="doc_subsubsection"> <a name="t_packed">Packed Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]996<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]997
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]998<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]999
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1000<p>A packed type is a simple derived type that represents a vector
1001of elements. Packed types are used when multiple primitive data
1002are operated in parallel using a single instruction (SIMD).
1003A packed type requires a size (number of
Chris Lattnerb8d172f2005-11-10 01:44:22 +0000[diff] [blame]1004elements) and an underlying primitive data type. Vectors must have a power
1005of two length (1, 2, 4, 8, 16 ...). Packed types are
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1006considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1007
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1008<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1009
1010<pre>
1011 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1012</pre>
1013
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1014<p>The number of elements is a constant integer value; elementtype may
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1015be any integral or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1016
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1017<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1018
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1019<table class="layout">
1020 <tr class="layout">
1021 <td class="left">
1022 <tt>&lt;4 x int&gt;</tt><br/>
1023 <tt>&lt;8 x float&gt;</tt><br/>
1024 <tt>&lt;2 x uint&gt;</tt><br/>
1025 </td>
1026 <td class="left">
1027 Packed vector of 4 integer values.<br/>
1028 Packed vector of 8 floating-point values.<br/>
1029 Packed vector of 2 unsigned integer values.<br/>
1030 </td>
1031 </tr>
1032</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1033</div>
1034
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1035<!-- _______________________________________________________________________ -->
1036<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1037<div class="doc_text">
1038
1039<h5>Overview:</h5>
1040
1041<p>Opaque types are used to represent unknown types in the system. This
1042corresponds (for example) to the C notion of a foward declared structure type.
1043In LLVM, opaque types can eventually be resolved to any type (not just a
1044structure type).</p>
1045
1046<h5>Syntax:</h5>
1047
1048<pre>
1049 opaque
1050</pre>
1051
1052<h5>Examples:</h5>
1053
1054<table class="layout">
1055 <tr class="layout">
1056 <td class="left">
1057 <tt>opaque</tt>
1058 </td>
1059 <td class="left">
1060 An opaque type.<br/>
1061 </td>
1062 </tr>
1063</table>
1064</div>
1065
1066
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1067<!-- *********************************************************************** -->
1068<div class="doc_section"> <a name="constants">Constants</a> </div>
1069<!-- *********************************************************************** -->
1070
1071<div class="doc_text">
1072
1073<p>LLVM has several different basic types of constants. This section describes
1074them all and their syntax.</p>
1075
1076</div>
1077
1078<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1079<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1080
1081<div class="doc_text">
1082
1083<dl>
1084 <dt><b>Boolean constants</b></dt>
1085
1086 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
1087 constants of the <tt><a href="#t_primitive">bool</a></tt> type.
1088 </dd>
1089
1090 <dt><b>Integer constants</b></dt>
1091
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1092 <dd>Standard integers (such as '4') are constants of the <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1093 href="#t_integer">integer</a> type. Negative numbers may be used with signed
1094 integer types.
1095 </dd>
1096
1097 <dt><b>Floating point constants</b></dt>
1098
1099 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1100 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1101 notation (see below). Floating point constants must have a <a
1102 href="#t_floating">floating point</a> type. </dd>
1103
1104 <dt><b>Null pointer constants</b></dt>
1105
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1106 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1107 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1108
1109</dl>
1110
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1111<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1112of floating point constants. For example, the form '<tt>double
11130x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
11144.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1115(and the only time that they are generated by the disassembler) is when a
1116floating point constant must be emitted but it cannot be represented as a
1117decimal floating point number. For example, NaN's, infinities, and other
1118special values are represented in their IEEE hexadecimal format so that
1119assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1120
1121</div>
1122
1123<!-- ======================================================================= -->
1124<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1125</div>
1126
1127<div class="doc_text">
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1128<p>Aggregate constants arise from aggregation of simple constants
1129and smaller aggregate constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1130
1131<dl>
1132 <dt><b>Structure constants</b></dt>
1133
1134 <dd>Structure constants are represented with notation similar to structure
1135 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1136 (<tt>{}</tt>)). For example: "<tt>{ int 4, float 17.0, int* %G }</tt>",
1137 where "<tt>%G</tt>" is declared as "<tt>%G = external global int</tt>". Structure constants
1138 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1139 types of elements must match those specified by the type.
1140 </dd>
1141
1142 <dt><b>Array constants</b></dt>
1143
1144 <dd>Array constants are represented with notation similar to array type
1145 definitions (a comma separated list of elements, surrounded by square brackets
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1146 (<tt>[]</tt>)). For example: "<tt>[ int 42, int 11, int 74 ]</tt>". Array
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1147 constants must have <a href="#t_array">array type</a>, and the number and
1148 types of elements must match those specified by the type.
1149 </dd>
1150
1151 <dt><b>Packed constants</b></dt>
1152
1153 <dd>Packed constants are represented with notation similar to packed type
1154 definitions (a comma separated list of elements, surrounded by
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1155 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; int 42,
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1156 int 11, int 74, int 100 &gt;</tt>". Packed constants must have <a
1157 href="#t_packed">packed type</a>, and the number and types of elements must
1158 match those specified by the type.
1159 </dd>
1160
1161 <dt><b>Zero initialization</b></dt>
1162
1163 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1164 value to zero of <em>any</em> type, including scalar and aggregate types.
1165 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]1166 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1167 initializers.
1168 </dd>
1169</dl>
1170
1171</div>
1172
1173<!-- ======================================================================= -->
1174<div class="doc_subsection">
1175 <a name="globalconstants">Global Variable and Function Addresses</a>
1176</div>
1177
1178<div class="doc_text">
1179
1180<p>The addresses of <a href="#globalvars">global variables</a> and <a
1181href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1182constants. These constants are explicitly referenced when the <a
1183href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1184href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1185file:</p>
1186
1187<pre>
1188 %X = global int 17
1189 %Y = global int 42
1190 %Z = global [2 x int*] [ int* %X, int* %Y ]
1191</pre>
1192
1193</div>
1194
1195<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1196<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1197<div class="doc_text">
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1198 <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]1199 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1200 a constant is permitted.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1201
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1202 <p>Undefined values indicate to the compiler that the program is well defined
1203 no matter what value is used, giving the compiler more freedom to optimize.
1204 </p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1205</div>
1206
1207<!-- ======================================================================= -->
1208<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1209</div>
1210
1211<div class="doc_text">
1212
1213<p>Constant expressions are used to allow expressions involving other constants
1214to be used as constants. Constant expressions may be of any <a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1215href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1216that does not have side effects (e.g. load and call are not supported). The
1217following is the syntax for constant expressions:</p>
1218
1219<dl>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1220 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1221 <dd>Truncate a constant to another type. The bit size of CST must be larger
1222 than the bit size of TYPE. Both types must be integral.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1223
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1224 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1225 <dd>Zero extend a constant to another type. The bit size of CST must be
1226 smaller or equal to the bit size of TYPE. Both types must be integral.</dd>
1227
1228 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1229 <dd>Sign extend a constant to another type. The bit size of CST must be
1230 smaller or equal to the bit size of TYPE. Both types must be integral.</dd>
1231
1232 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1233 <dd>Truncate a floating point constant to another floating point type. The
1234 size of CST must be larger than the size of TYPE. Both types must be
1235 floating point.</dd>
1236
1237 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1238 <dd>Floating point extend a constant to another type. The size of CST must be
1239 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1240
1241 <dt><b><tt>fp2uint ( CST to TYPE )</tt></b></dt>
1242 <dd>Convert a floating point constant to the corresponding unsigned integer
1243 constant. TYPE must be an integer type. CST must be floating point. If the
1244 value won't fit in the integer type, the results are undefined.</dd>
1245
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1246 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1247 <dd>Convert a floating point constant to the corresponding signed integer
1248 constant. TYPE must be an integer type. CST must be floating point. If the
1249 value won't fit in the integer type, the results are undefined.</dd>
1250
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1251 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1252 <dd>Convert an unsigned integer constant to the corresponding floating point
1253 constant. TYPE must be floating point. CST must be of integer type. If the
1254 value won't fit in the floating point type, the results are undefined.</dd>
1255
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1256 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1257 <dd>Convert a signed integer constant to the corresponding floating point
1258 constant. TYPE must be floating point. CST must be of integer type. If the
1259 value won't fit in the floating point type, the results are undefined.</dd>
1260
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]1261 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1262 <dd>Convert a pointer typed constant to the corresponding integer constant
1263 TYPE must be an integer type. CST must be of pointer type. The CST value is
1264 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1265
1266 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1267 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1268 pointer type. CST must be of integer type. The CST value is zero extended,
1269 truncated, or unchanged to make it fit in a pointer size. This one is
1270 <i>really</i> dangerous!</dd>
1271
1272 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1273 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1274 identical (same number of bits). The conversion is done as if the CST value
1275 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]1276 with this operator, just the type. This can be used for conversion of
1277 packed types to any other type, as long as they have the same bit width. For
1278 pointers it is only valid to cast to another pointer type.
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1279 </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1280
1281 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1282
1283 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1284 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1285 instruction, the index list may have zero or more indexes, which are required
1286 to make sense for the type of "CSTPTR".</dd>
1287
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1288 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1289
1290 <dd>Perform the <a href="#i_select">select operation</a> on
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1291 constants.</dd>
1292
1293 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1294 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1295
1296 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1297 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1298
1299 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1300
1301 <dd>Perform the <a href="#i_extractelement">extractelement
1302 operation</a> on constants.
1303
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1304 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1305
1306 <dd>Perform the <a href="#i_insertelement">insertelement
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1307 operation</a> on constants.</dd>
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1308
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1309
1310 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1311
1312 <dd>Perform the <a href="#i_shufflevector">shufflevector
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1313 operation</a> on constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1314
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1315 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1316
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1317 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1318 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1319 binary</a> operations. The constraints on operands are the same as those for
1320 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1321 values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1322</dl>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1323</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]1324
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1325<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1326<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1327<!-- *********************************************************************** -->
1328
1329<!-- ======================================================================= -->
1330<div class="doc_subsection">
1331<a name="inlineasm">Inline Assembler Expressions</a>
1332</div>
1333
1334<div class="doc_text">
1335
1336<p>
1337LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1338Module-Level Inline Assembly</a>) through the use of a special value. This
1339value represents the inline assembler as a string (containing the instructions
1340to emit), a list of operand constraints (stored as a string), and a flag that
1341indicates whether or not the inline asm expression has side effects. An example
1342inline assembler expression is:
1343</p>
1344
1345<pre>
1346 int(int) asm "bswap $0", "=r,r"
1347</pre>
1348
1349<p>
1350Inline assembler expressions may <b>only</b> be used as the callee operand of
1351a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1352</p>
1353
1354<pre>
1355 %X = call int asm "<a href="#i_bswap">bswap</a> $0", "=r,r"(int %Y)
1356</pre>
1357
1358<p>
1359Inline asms with side effects not visible in the constraint list must be marked
1360as having side effects. This is done through the use of the
1361'<tt>sideeffect</tt>' keyword, like so:
1362</p>
1363
1364<pre>
1365 call void asm sideeffect "eieio", ""()
1366</pre>
1367
1368<p>TODO: The format of the asm and constraints string still need to be
1369documented here. Constraints on what can be done (e.g. duplication, moving, etc
1370need to be documented).
1371</p>
1372
1373</div>
1374
1375<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1376<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1377<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1378
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1379<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1380
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1381<p>The LLVM instruction set consists of several different
1382classifications of instructions: <a href="#terminators">terminator
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1383instructions</a>, <a href="#binaryops">binary instructions</a>,
1384<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1385 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1386instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1387
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1388</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1389
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1390<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1391<div class="doc_subsection"> <a name="terminators">Terminator
1392Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1393
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1394<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1395
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1396<p>As mentioned <a href="#functionstructure">previously</a>, every
1397basic block in a program ends with a "Terminator" instruction, which
1398indicates which block should be executed after the current block is
1399finished. These terminator instructions typically yield a '<tt>void</tt>'
1400value: they produce control flow, not values (the one exception being
1401the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1402<p>There are six different terminator instructions: the '<a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1403 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1404instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1405the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1406 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1407 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1408
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1409</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1410
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1411<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1412<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1413Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1414<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1415<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1416<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]1417 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1418</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1419<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1420<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1421value) from a function back to the caller.</p>
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]1422<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1423returns a value and then causes control flow, and one that just causes
1424control flow to occur.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1425<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1426<p>The '<tt>ret</tt>' instruction may return any '<a
1427 href="#t_firstclass">first class</a>' type. Notice that a function is
1428not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
1429instruction inside of the function that returns a value that does not
1430match the return type of the function.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1431<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1432<p>When the '<tt>ret</tt>' instruction is executed, control flow
1433returns back to the calling function's context. If the caller is a "<a
John Criswellfa081872004-06-25 15:16:57 +0000[diff] [blame]1434 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1435the instruction after the call. If the caller was an "<a
1436 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1437at the beginning of the "normal" destination block. If the instruction
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1438returns a value, that value shall set the call or invoke instruction's
1439return value.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1440<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1441<pre> ret int 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1442 ret void <i>; Return from a void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1443</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1444</div>
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_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1447<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1448<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1449<pre> br bool &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1450</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1451<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1452<p>The '<tt>br</tt>' instruction is used to cause control flow to
1453transfer to a different basic block in the current function. There are
1454two forms of this instruction, corresponding to a conditional branch
1455and an unconditional branch.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1456<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1457<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
1458single '<tt>bool</tt>' value and two '<tt>label</tt>' values. The
1459unconditional form of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>'
1460value as a target.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1461<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1462<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>bool</tt>'
1463argument is evaluated. If the value is <tt>true</tt>, control flows
1464to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1465control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1466<h5>Example:</h5>
Reid Spencer36d68e42006-11-18 21:55:45 +0000[diff] [blame]1467<pre>Test:<br> %cond = <a href="#i_icmp">icmp</a> eq, int %a, %b<br> br bool %cond, label %IfEqual, label %IfUnequal<br>IfEqual:<br> <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1468 href="#i_ret">ret</a> int 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> int 0<br></pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1469</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1470<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1471<div class="doc_subsubsection">
1472 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1473</div>
1474
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1475<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1476<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1477
1478<pre>
1479 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1480</pre>
1481
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1482<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1483
1484<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1485several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1486instruction, allowing a branch to occur to one of many possible
1487destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1488
1489
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1490<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1491
1492<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1493comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1494an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1495table is not allowed to contain duplicate constant entries.</p>
1496
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1497<h5>Semantics:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1498
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1499<p>The <tt>switch</tt> instruction specifies a table of values and
1500destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1501table is searched for the given value. If the value is found, control flow is
1502transfered to the corresponding destination; otherwise, control flow is
1503transfered to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1504
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1505<h5>Implementation:</h5>
1506
1507<p>Depending on properties of the target machine and the particular
1508<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1509ways. For example, it could be generated as a series of chained conditional
1510branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1511
1512<h5>Example:</h5>
1513
1514<pre>
1515 <i>; Emulate a conditional br instruction</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1516 %Val = <a href="#i_zext">zext</a> bool %value to int
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1517 switch int %Val, label %truedest [int 0, label %falsedest ]
1518
1519 <i>; Emulate an unconditional br instruction</i>
1520 switch uint 0, label %dest [ ]
1521
1522 <i>; Implement a jump table:</i>
1523 switch uint %val, label %otherwise [ uint 0, label %onzero
1524 uint 1, label %onone
1525 uint 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1526</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1527</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1528
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1529<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1530<div class="doc_subsubsection">
1531 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1532</div>
1533
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1534<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1535
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1536<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1537
1538<pre>
1539 &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]1540 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1541</pre>
1542
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1543<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1544
1545<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1546function, with the possibility of control flow transfer to either the
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1547'<tt>normal</tt>' label or the
1548'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1549"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1550"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1551href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
1552continued at the dynamically nearest "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1553
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1554<h5>Arguments:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1555
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1556<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1557
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1558<ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1559 <li>
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1560 The optional "cconv" marker indicates which <a href="callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1561 convention</a> the call should use. If none is specified, the call defaults
1562 to using C calling conventions.
1563 </li>
1564 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1565 function value being invoked. In most cases, this is a direct function
1566 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1567 an arbitrary pointer to function value.
1568 </li>
1569
1570 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1571 function to be invoked. </li>
1572
1573 <li>'<tt>function args</tt>': argument list whose types match the function
1574 signature argument types. If the function signature indicates the function
1575 accepts a variable number of arguments, the extra arguments can be
1576 specified. </li>
1577
1578 <li>'<tt>normal label</tt>': the label reached when the called function
1579 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1580
1581 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1582 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1583
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1584</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1585
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1586<h5>Semantics:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1587
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1588<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1589href="#i_call">call</a></tt>' instruction in most regards. The primary
1590difference is that it establishes an association with a label, which is used by
1591the runtime library to unwind the stack.</p>
1592
1593<p>This instruction is used in languages with destructors to ensure that proper
1594cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1595exception. Additionally, this is important for implementation of
1596'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1597
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1598<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1599<pre>
1600 %retval = invoke int %Test(int 15) to label %Continue
Chris Lattner76b8a332006-05-14 18:23:06 +0000[diff] [blame]1601 unwind label %TestCleanup <i>; {int}:retval set</i>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1602 %retval = invoke <a href="#callingconv">coldcc</a> int %Test(int 15) to label %Continue
Chris Lattner76b8a332006-05-14 18:23:06 +0000[diff] [blame]1603 unwind label %TestCleanup <i>; {int}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1604</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1605</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1606
1607
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1608<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1609
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1610<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1611Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1612
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1613<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1614
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1615<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1616<pre>
1617 unwind
1618</pre>
1619
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1620<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1621
1622<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
1623at the first callee in the dynamic call stack which used an <a
1624href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
1625primarily used to implement exception handling.</p>
1626
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1627<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1628
1629<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
1630immediately halt. The dynamic call stack is then searched for the first <a
1631href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
1632execution continues at the "exceptional" destination block specified by the
1633<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
1634dynamic call chain, undefined behavior results.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1635</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1636
1637<!-- _______________________________________________________________________ -->
1638
1639<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
1640Instruction</a> </div>
1641
1642<div class="doc_text">
1643
1644<h5>Syntax:</h5>
1645<pre>
1646 unreachable
1647</pre>
1648
1649<h5>Overview:</h5>
1650
1651<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
1652instruction is used to inform the optimizer that a particular portion of the
1653code is not reachable. This can be used to indicate that the code after a
1654no-return function cannot be reached, and other facts.</p>
1655
1656<h5>Semantics:</h5>
1657
1658<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
1659</div>
1660
1661
1662
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1663<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1664<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1665<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1666<p>Binary operators are used to do most of the computation in a
1667program. They require two operands, execute an operation on them, and
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1668produce a single value. The operands might represent
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1669multiple data, as is the case with the <a href="#t_packed">packed</a> data type.
1670The result value of a binary operator is not
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1671necessarily the same type as its operands.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1672<p>There are several different binary operators:</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1673</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1674<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1675<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
1676Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1677<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1678<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1679<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]1680</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1681<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1682<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1683<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1684<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1685 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
1686 This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1687Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1688<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1689<p>The value produced is the integer or floating point sum of the two
1690operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1691<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1692<pre> &lt;result&gt; = add int 4, %var <i>; yields {int}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1693</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1694</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1695<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1696<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
1697Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1698<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1699<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1700<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]1701</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1702<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1703<p>The '<tt>sub</tt>' instruction returns the difference of its two
1704operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1705<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
1706instruction present in most other intermediate representations.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1707<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1708<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1709 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1710values.
1711This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1712Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1713<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1714<p>The value produced is the integer or floating point difference of
1715the two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1716<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1717<pre> &lt;result&gt; = sub int 4, %var <i>; yields {int}:result = 4 - %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1718 &lt;result&gt; = sub int 0, %val <i>; yields {int}:result = -%var</i>
1719</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1720</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1721<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1722<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
1723Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1724<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1725<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1726<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]1727</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1728<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1729<p>The '<tt>mul</tt>' instruction returns the product of its two
1730operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1731<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1732<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1733 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1734values.
1735This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1736Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1737<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1738<p>The value produced is the integer or floating point product of the
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1739two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1740<p>There is no signed vs unsigned multiplication. The appropriate
1741action is taken based on the type of the operand.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1742<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1743<pre> &lt;result&gt; = mul int 4, %var <i>; yields {int}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1744</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1745</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1746<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1747<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
1748</a></div>
1749<div class="doc_text">
1750<h5>Syntax:</h5>
1751<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1752</pre>
1753<h5>Overview:</h5>
1754<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
1755operands.</p>
1756<h5>Arguments:</h5>
1757<p>The two arguments to the '<tt>udiv</tt>' instruction must be
1758<a href="#t_integer">integer</a> values. Both arguments must have identical
1759types. This instruction can also take <a href="#t_packed">packed</a> versions
1760of the values in which case the elements must be integers.</p>
1761<h5>Semantics:</h5>
1762<p>The value produced is the unsigned integer quotient of the two operands. This
1763instruction always performs an unsigned division operation, regardless of
1764whether the arguments are unsigned or not.</p>
1765<h5>Example:</h5>
1766<pre> &lt;result&gt; = udiv uint 4, %var <i>; yields {uint}:result = 4 / %var</i>
1767</pre>
1768</div>
1769<!-- _______________________________________________________________________ -->
1770<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
1771</a> </div>
1772<div class="doc_text">
1773<h5>Syntax:</h5>
1774<pre> &lt;result&gt; = sdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1775</pre>
1776<h5>Overview:</h5>
1777<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
1778operands.</p>
1779<h5>Arguments:</h5>
1780<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
1781<a href="#t_integer">integer</a> values. Both arguments must have identical
1782types. This instruction can also take <a href="#t_packed">packed</a> versions
1783of the values in which case the elements must be integers.</p>
1784<h5>Semantics:</h5>
1785<p>The value produced is the signed integer quotient of the two operands. This
1786instruction always performs a signed division operation, regardless of whether
1787the arguments are signed or not.</p>
1788<h5>Example:</h5>
1789<pre> &lt;result&gt; = sdiv int 4, %var <i>; yields {int}:result = 4 / %var</i>
1790</pre>
1791</div>
1792<!-- _______________________________________________________________________ -->
1793<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1794Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1795<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1796<h5>Syntax:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1797<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]1798</pre>
1799<h5>Overview:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1800<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1801operands.</p>
1802<h5>Arguments:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1803<p>The two arguments to the '<tt>div</tt>' instruction must be
1804<a href="#t_floating">floating point</a> values. Both arguments must have
1805identical types. This instruction can also take <a href="#t_packed">packed</a>
1806versions of the values in which case the elements must be floating point.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1807<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1808<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1809<h5>Example:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1810<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]1811</pre>
1812</div>
1813<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1814<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
1815</div>
1816<div class="doc_text">
1817<h5>Syntax:</h5>
1818<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1819</pre>
1820<h5>Overview:</h5>
1821<p>The '<tt>urem</tt>' instruction returns the remainder from the
1822unsigned division of its two arguments.</p>
1823<h5>Arguments:</h5>
1824<p>The two arguments to the '<tt>urem</tt>' instruction must be
1825<a href="#t_integer">integer</a> values. Both arguments must have identical
1826types.</p>
1827<h5>Semantics:</h5>
1828<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
1829This instruction always performs an unsigned division to get the remainder,
1830regardless of whether the arguments are unsigned or not.</p>
1831<h5>Example:</h5>
1832<pre> &lt;result&gt; = urem uint 4, %var <i>; yields {uint}:result = 4 % %var</i>
1833</pre>
1834
1835</div>
1836<!-- _______________________________________________________________________ -->
1837<div class="doc_subsubsection"> <a name="i_srem">'<tt>srem</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1838Instruction</a> </div>
1839<div class="doc_text">
1840<h5>Syntax:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1841<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]1842</pre>
1843<h5>Overview:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1844<p>The '<tt>srem</tt>' instruction returns the remainder from the
1845signed division of its two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1846<h5>Arguments:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1847<p>The two arguments to the '<tt>srem</tt>' instruction must be
1848<a href="#t_integer">integer</a> values. Both arguments must have identical
1849types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1850<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1851<p>This instruction returns the <i>remainder</i> of a division (where the result
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1852has the same sign as the divisor), not the <i>modulus</i> (where the
1853result has the same sign as the dividend) of a value. For more
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1854information about the difference, see <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1855 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
1856Math Forum</a>.</p>
1857<h5>Example:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1858<pre> &lt;result&gt; = srem int 4, %var <i>; yields {int}:result = 4 % %var</i>
1859</pre>
1860
1861</div>
1862<!-- _______________________________________________________________________ -->
1863<div class="doc_subsubsection"> <a name="i_frem">'<tt>frem</tt>'
1864Instruction</a> </div>
1865<div class="doc_text">
1866<h5>Syntax:</h5>
1867<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1868</pre>
1869<h5>Overview:</h5>
1870<p>The '<tt>frem</tt>' instruction returns the remainder from the
1871division of its two operands.</p>
1872<h5>Arguments:</h5>
1873<p>The two arguments to the '<tt>frem</tt>' instruction must be
1874<a href="#t_floating">floating point</a> values. Both arguments must have
1875identical types.</p>
1876<h5>Semantics:</h5>
1877<p>This instruction returns the <i>remainder</i> of a division.</p>
1878<h5>Example:</h5>
1879<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]1880</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1881</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]1882
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1883<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1884<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
1885Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1886<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1887<p>Bitwise binary operators are used to do various forms of
1888bit-twiddling in a program. They are generally very efficient
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1889instructions and can commonly be strength reduced from other
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1890instructions. They require two operands, execute an operation on them,
1891and produce a single value. The resulting value of the bitwise binary
1892operators is always the same type as its first operand.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1893</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1894<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1895<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
1896Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1897<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1898<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1899<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]1900</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1901<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1902<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
1903its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1904<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1905<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1906 href="#t_integral">integral</a> values. Both arguments must have
1907identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1908<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1909<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1910<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1911<div style="align: center">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1912<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1913 <tbody>
1914 <tr>
1915 <td>In0</td>
1916 <td>In1</td>
1917 <td>Out</td>
1918 </tr>
1919 <tr>
1920 <td>0</td>
1921 <td>0</td>
1922 <td>0</td>
1923 </tr>
1924 <tr>
1925 <td>0</td>
1926 <td>1</td>
1927 <td>0</td>
1928 </tr>
1929 <tr>
1930 <td>1</td>
1931 <td>0</td>
1932 <td>0</td>
1933 </tr>
1934 <tr>
1935 <td>1</td>
1936 <td>1</td>
1937 <td>1</td>
1938 </tr>
1939 </tbody>
1940</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1941</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1942<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1943<pre> &lt;result&gt; = and int 4, %var <i>; yields {int}:result = 4 &amp; %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1944 &lt;result&gt; = and int 15, 40 <i>; yields {int}:result = 8</i>
1945 &lt;result&gt; = and int 4, 8 <i>; yields {int}:result = 0</i>
1946</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1947</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1948<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1949<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1950<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1951<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1952<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]1953</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1954<h5>Overview:</h5>
1955<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
1956or of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1957<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1958<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1959 href="#t_integral">integral</a> values. Both arguments must have
1960identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1961<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1962<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1963<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1964<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1965<table border="1" cellspacing="0" cellpadding="4">
1966 <tbody>
1967 <tr>
1968 <td>In0</td>
1969 <td>In1</td>
1970 <td>Out</td>
1971 </tr>
1972 <tr>
1973 <td>0</td>
1974 <td>0</td>
1975 <td>0</td>
1976 </tr>
1977 <tr>
1978 <td>0</td>
1979 <td>1</td>
1980 <td>1</td>
1981 </tr>
1982 <tr>
1983 <td>1</td>
1984 <td>0</td>
1985 <td>1</td>
1986 </tr>
1987 <tr>
1988 <td>1</td>
1989 <td>1</td>
1990 <td>1</td>
1991 </tr>
1992 </tbody>
1993</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1994</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1995<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1996<pre> &lt;result&gt; = or int 4, %var <i>; yields {int}:result = 4 | %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1997 &lt;result&gt; = or int 15, 40 <i>; yields {int}:result = 47</i>
1998 &lt;result&gt; = or int 4, 8 <i>; yields {int}:result = 12</i>
1999</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2000</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2001<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2002<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2003Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2004<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2005<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2006<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]2007</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2008<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2009<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2010or of its two operands. The <tt>xor</tt> is used to implement the
2011"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2012<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2013<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2014 href="#t_integral">integral</a> values. Both arguments must have
2015identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2016<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2017<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2018<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2019<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2020<table border="1" cellspacing="0" cellpadding="4">
2021 <tbody>
2022 <tr>
2023 <td>In0</td>
2024 <td>In1</td>
2025 <td>Out</td>
2026 </tr>
2027 <tr>
2028 <td>0</td>
2029 <td>0</td>
2030 <td>0</td>
2031 </tr>
2032 <tr>
2033 <td>0</td>
2034 <td>1</td>
2035 <td>1</td>
2036 </tr>
2037 <tr>
2038 <td>1</td>
2039 <td>0</td>
2040 <td>1</td>
2041 </tr>
2042 <tr>
2043 <td>1</td>
2044 <td>1</td>
2045 <td>0</td>
2046 </tr>
2047 </tbody>
2048</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2049</div>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2050<p> </p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2051<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2052<pre> &lt;result&gt; = xor int 4, %var <i>; yields {int}:result = 4 ^ %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2053 &lt;result&gt; = xor int 15, 40 <i>; yields {int}:result = 39</i>
2054 &lt;result&gt; = xor int 4, 8 <i>; yields {int}:result = 12</i>
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2055 &lt;result&gt; = xor int %V, -1 <i>; yields {int}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2056</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2057</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2058<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2059<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2060Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2061<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2062<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2063<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, ubyte &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2064</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2065<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2066<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2067the left a specified number of bits.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2068<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2069<p>The first argument to the '<tt>shl</tt>' instruction must be an <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2070 href="#t_integer">integer</a> type. The second argument must be an '<tt>ubyte</tt>'
2071type.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2072<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2073<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]2074<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2075<pre> &lt;result&gt; = shl int 4, ubyte %var <i>; yields {int}:result = 4 &lt;&lt; %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2076 &lt;result&gt; = shl int 4, ubyte 2 <i>; yields {int}:result = 16</i>
2077 &lt;result&gt; = shl int 1, ubyte 10 <i>; yields {int}:result = 1024</i>
2078</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2079</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2080<!-- _______________________________________________________________________ -->
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2081<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2082Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2083<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2084<h5>Syntax:</h5>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2085<pre> &lt;result&gt; = lshr &lt;ty&gt; &lt;var1&gt;, ubyte &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2086</pre>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2087
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2088<h5>Overview:</h5>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2089<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
2090operand shifted to the right a specified number of bits.</p>
2091
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2092<h5>Arguments:</h5>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2093<p>The first argument to the '<tt>lshr</tt>' instruction must be an <a
2094 href="#t_integer">integer</a> type. The second argument must be an '<tt>ubyte</tt>' type.</p>
2095
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2096<h5>Semantics:</h5>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2097<p>This instruction always performs a logical shift right operation, regardless
2098of whether the arguments are unsigned or not. The <tt>var2</tt> most significant
2099bits will be filled with zero bits after the shift.</p>
2100
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2101<h5>Example:</h5>
Reid Spencer3822ff52006-11-08 06:47:33 +0000[diff] [blame]2102<pre>
2103 &lt;result&gt; = lshr uint 4, ubyte 1 <i>; yields {uint}:result = 2</i>
2104 &lt;result&gt; = lshr int 4, ubyte 2 <i>; yields {uint}:result = 1</i>
2105 &lt;result&gt; = lshr sbyte 4, ubyte 3 <i>; yields {sbyte}:result = 0</i>
2106 &lt;result&gt; = lshr sbyte -2, ubyte 1 <i>; yields {sbyte}:result = 0x7FFFFFFF </i>
2107</pre>
2108</div>
2109
2110<!-- ======================================================================= -->
2111<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2112Instruction</a> </div>
2113<div class="doc_text">
2114
2115<h5>Syntax:</h5>
2116<pre> &lt;result&gt; = ashr &lt;ty&gt; &lt;var1&gt;, ubyte &lt;var2&gt; <i>; yields {ty}:result</i>
2117</pre>
2118
2119<h5>Overview:</h5>
2120<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
2121operand shifted to the right a specified number of bits.</p>
2122
2123<h5>Arguments:</h5>
2124<p>The first argument to the '<tt>ashr</tt>' instruction must be an
2125<a href="#t_integer">integer</a> type. The second argument must be an
2126'<tt>ubyte</tt>' type.</p>
2127
2128<h5>Semantics:</h5>
2129<p>This instruction always performs an arithmetic shift right operation,
2130regardless of whether the arguments are signed or not. The <tt>var2</tt> most
2131significant bits will be filled with the sign bit of <tt>var1</tt>.</p>
2132
2133<h5>Example:</h5>
2134<pre>
2135 &lt;result&gt; = ashr uint 4, ubyte 1 <i>; yields {uint}:result = 2</i>
2136 &lt;result&gt; = ashr int 4, ubyte 2 <i>; yields {int}:result = 1</i>
2137 &lt;result&gt; = ashr ubyte 4, ubyte 3 <i>; yields {ubyte}:result = 0</i>
2138 &lt;result&gt; = ashr sbyte -2, ubyte 1 <i>; yields {sbyte}:result = -1</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2139</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2140</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2141
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2142<!-- ======================================================================= -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2143<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2144 <a name="vectorops">Vector Operations</a>
2145</div>
2146
2147<div class="doc_text">
2148
2149<p>LLVM supports several instructions to represent vector operations in a
2150target-independent manner. This instructions cover the element-access and
2151vector-specific operations needed to process vectors effectively. While LLVM
2152does directly support these vector operations, many sophisticated algorithms
2153will want to use target-specific intrinsics to take full advantage of a specific
2154target.</p>
2155
2156</div>
2157
2158<!-- _______________________________________________________________________ -->
2159<div class="doc_subsubsection">
2160 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2161</div>
2162
2163<div class="doc_text">
2164
2165<h5>Syntax:</h5>
2166
2167<pre>
2168 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, uint &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
2169</pre>
2170
2171<h5>Overview:</h5>
2172
2173<p>
2174The '<tt>extractelement</tt>' instruction extracts a single scalar
2175element from a packed vector at a specified index.
2176</p>
2177
2178
2179<h5>Arguments:</h5>
2180
2181<p>
2182The first operand of an '<tt>extractelement</tt>' instruction is a
2183value of <a href="#t_packed">packed</a> type. The second operand is
2184an index indicating the position from which to extract the element.
2185The index may be a variable.</p>
2186
2187<h5>Semantics:</h5>
2188
2189<p>
2190The result is a scalar of the same type as the element type of
2191<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2192<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2193results are undefined.
2194</p>
2195
2196<h5>Example:</h5>
2197
2198<pre>
2199 %result = extractelement &lt;4 x int&gt; %vec, uint 0 <i>; yields int</i>
2200</pre>
2201</div>
2202
2203
2204<!-- _______________________________________________________________________ -->
2205<div class="doc_subsubsection">
2206 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2207</div>
2208
2209<div class="doc_text">
2210
2211<h5>Syntax:</h5>
2212
2213<pre>
2214 &lt;result&gt; = insertelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, &lt;ty&gt; &lt;elt&gt, uint &lt;idx&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
2215</pre>
2216
2217<h5>Overview:</h5>
2218
2219<p>
2220The '<tt>insertelement</tt>' instruction inserts a scalar
2221element into a packed vector at a specified index.
2222</p>
2223
2224
2225<h5>Arguments:</h5>
2226
2227<p>
2228The first operand of an '<tt>insertelement</tt>' instruction is a
2229value of <a href="#t_packed">packed</a> type. The second operand is a
2230scalar value whose type must equal the element type of the first
2231operand. The third operand is an index indicating the position at
2232which to insert the value. The index may be a variable.</p>
2233
2234<h5>Semantics:</h5>
2235
2236<p>
2237The result is a packed vector of the same type as <tt>val</tt>. Its
2238element values are those of <tt>val</tt> except at position
2239<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2240exceeds the length of <tt>val</tt>, the results are undefined.
2241</p>
2242
2243<h5>Example:</h5>
2244
2245<pre>
2246 %result = insertelement &lt;4 x int&gt; %vec, int 1, uint 0 <i>; yields &lt;4 x int&gt;</i>
2247</pre>
2248</div>
2249
2250<!-- _______________________________________________________________________ -->
2251<div class="doc_subsubsection">
2252 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2253</div>
2254
2255<div class="doc_text">
2256
2257<h5>Syntax:</h5>
2258
2259<pre>
2260 &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 uint&gt; &lt;mask&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
2261</pre>
2262
2263<h5>Overview:</h5>
2264
2265<p>
2266The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2267from two input vectors, returning a vector of the same type.
2268</p>
2269
2270<h5>Arguments:</h5>
2271
2272<p>
2273The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2274with types that match each other and types that match the result of the
2275instruction. The third argument is a shuffle mask, which has the same number
2276of elements as the other vector type, but whose element type is always 'uint'.
2277</p>
2278
2279<p>
2280The shuffle mask operand is required to be a constant vector with either
2281constant integer or undef values.
2282</p>
2283
2284<h5>Semantics:</h5>
2285
2286<p>
2287The elements of the two input vectors are numbered from left to right across
2288both of the vectors. The shuffle mask operand specifies, for each element of
2289the result vector, which element of the two input registers the result element
2290gets. The element selector may be undef (meaning "don't care") and the second
2291operand may be undef if performing a shuffle from only one vector.
2292</p>
2293
2294<h5>Example:</h5>
2295
2296<pre>
2297 %result = shufflevector &lt;4 x int&gt; %v1, &lt;4 x int&gt; %v2,
2298 &lt;4 x uint&gt; &lt;uint 0, uint 4, uint 1, uint 5&gt; <i>; yields &lt;4 x int&gt;</i>
2299 %result = shufflevector &lt;4 x int&gt; %v1, &lt;4 x int&gt; undef,
2300 &lt;4 x uint&gt; &lt;uint 0, uint 1, uint 2, uint 3&gt; <i>; yields &lt;4 x int&gt;</i> - Identity shuffle.
2301</pre>
2302</div>
2303
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]2304
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2305<!-- ======================================================================= -->
2306<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2307 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2308</div>
2309
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2310<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2311
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2312<p>A key design point of an SSA-based representation is how it
2313represents memory. In LLVM, no memory locations are in SSA form, which
2314makes things very simple. This section describes how to read, write,
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2315allocate, and free memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2316
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2317</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2318
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2319<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2320<div class="doc_subsubsection">
2321 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2322</div>
2323
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2324<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2325
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2326<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2327
2328<pre>
2329 &lt;result&gt; = malloc &lt;type&gt;[, uint &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2330</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2331
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2332<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2333
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2334<p>The '<tt>malloc</tt>' instruction allocates memory from the system
2335heap and returns a pointer to it.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2336
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2337<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2338
2339<p>The '<tt>malloc</tt>' instruction allocates
2340<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswell6e4ca612004-02-24 16:13:56 +0000[diff] [blame]2341bytes of memory from the operating system and returns a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2342appropriate type to the program. If "NumElements" is specified, it is the
2343number of elements allocated. If an alignment is specified, the value result
2344of the allocation is guaranteed to be aligned to at least that boundary. If
2345not specified, or if zero, the target can choose to align the allocation on any
2346convenient boundary.</p>
2347
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2348<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2349
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2350<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2351
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2352<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
2353a pointer is returned.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2354
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2355<h5>Example:</h5>
2356
2357<pre>
2358 %array = malloc [4 x ubyte ] <i>; yields {[%4 x ubyte]*}:array</i>
2359
2360 %size = <a href="#i_add">add</a> uint 2, 2 <i>; yields {uint}:size = uint 4</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2361 %array1 = malloc ubyte, uint 4 <i>; yields {ubyte*}:array1</i>
2362 %array2 = malloc [12 x ubyte], uint %size <i>; yields {[12 x ubyte]*}:array2</i>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2363 %array3 = malloc int, uint 4, align 1024 <i>; yields {int*}:array3</i>
2364 %array4 = malloc int, align 1024 <i>; yields {int*}:array4</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2365</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2366</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2367
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2368<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2369<div class="doc_subsubsection">
2370 <a name="i_free">'<tt>free</tt>' Instruction</a>
2371</div>
2372
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2373<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2374
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2375<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2376
2377<pre>
2378 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2379</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2380
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2381<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2382
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2383<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2384memory heap to be reallocated in the future.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2385
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2386<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2387
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2388<p>'<tt>value</tt>' shall be a pointer value that points to a value
2389that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
2390instruction.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2391
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2392<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2393
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2394<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2395after this instruction executes.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2396
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2397<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2398
2399<pre>
2400 %array = <a href="#i_malloc">malloc</a> [4 x ubyte] <i>; yields {[4 x ubyte]*}:array</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2401 free [4 x ubyte]* %array
2402</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2403</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2404
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2405<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2406<div class="doc_subsubsection">
2407 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
2408</div>
2409
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2410<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2411
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2412<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2413
2414<pre>
2415 &lt;result&gt; = alloca &lt;type&gt;[, uint &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2416</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2417
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2418<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2419
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2420<p>The '<tt>alloca</tt>' instruction allocates memory on the current
2421stack frame of the procedure that is live until the current function
2422returns to its caller.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2423
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2424<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2425
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2426<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2427bytes of memory on the runtime stack, returning a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2428appropriate type to the program. If "NumElements" is specified, it is the
2429number of elements allocated. If an alignment is specified, the value result
2430of the allocation is guaranteed to be aligned to at least that boundary. If
2431not specified, or if zero, the target can choose to align the allocation on any
2432convenient boundary.</p>
2433
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2434<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2435
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2436<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2437
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2438<p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2439memory is automatically released when the function returns. The '<tt>alloca</tt>'
2440instruction is commonly used to represent automatic variables that must
2441have an address available. When the function returns (either with the <tt><a
John Criswelldae2e932005-05-12 16:55:34 +0000[diff] [blame]2442 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]2443instructions), the memory is reclaimed.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2444
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2445<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2446
2447<pre>
2448 %ptr = alloca int <i>; yields {int*}:ptr</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2449 %ptr = alloca int, uint 4 <i>; yields {int*}:ptr</i>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2450 %ptr = alloca int, uint 4, align 1024 <i>; yields {int*}:ptr</i>
2451 %ptr = alloca int, align 1024 <i>; yields {int*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2452</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2453</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2454
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2455<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2456<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
2457Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2458<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2459<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2460<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]2461<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2462<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2463<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2464<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2465address from which to load. The pointer must point to a <a
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]2466 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2467marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2468the number or order of execution of this <tt>load</tt> with other
2469volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
2470instructions. </p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2471<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2472<p>The location of memory pointed to is loaded.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2473<h5>Examples:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2474<pre> %ptr = <a href="#i_alloca">alloca</a> int <i>; yields {int*}:ptr</i>
2475 <a
2476 href="#i_store">store</a> int 3, int* %ptr <i>; yields {void}</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2477 %val = load int* %ptr <i>; yields {int}:val = int 3</i>
2478</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2479</div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2480<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2481<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
2482Instruction</a> </div>
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]2483<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2484<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2485<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]2486 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]2487</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2488<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2489<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2490<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2491<p>There are two arguments to the '<tt>store</tt>' instruction: a value
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2492to 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]2493operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2494operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2495optimizer is not allowed to modify the number or order of execution of
2496this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
2497 href="#i_store">store</a></tt> instructions.</p>
2498<h5>Semantics:</h5>
2499<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
2500at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2501<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2502<pre> %ptr = <a href="#i_alloca">alloca</a> int <i>; yields {int*}:ptr</i>
2503 <a
2504 href="#i_store">store</a> int 3, int* %ptr <i>; yields {void}</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2505 %val = load int* %ptr <i>; yields {int}:val = int 3</i>
2506</pre>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2507</div>
2508
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2509<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2510<div class="doc_subsubsection">
2511 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
2512</div>
2513
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2514<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2515<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2516<pre>
2517 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
2518</pre>
2519
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2520<h5>Overview:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2521
2522<p>
2523The '<tt>getelementptr</tt>' instruction is used to get the address of a
2524subelement of an aggregate data structure.</p>
2525
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2526<h5>Arguments:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2527
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2528<p>This instruction takes a list of integer operands that indicate what
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2529elements of the aggregate object to index to. The actual types of the arguments
2530provided depend on the type of the first pointer argument. The
2531'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2532levels of a structure or to a specific index in an array. When indexing into a
Reid Spencer42ddd842006-12-03 16:53:48 +0000[diff] [blame]2533structure, only <tt>uint</tt> integer constants are allowed. When indexing
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2534into an array or pointer, only integers of 32 or 64 bits are allowed, and will
2535be sign extended to 64-bit values.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2536
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2537<p>For example, let's consider a C code fragment and how it gets
2538compiled to LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2539
2540<pre>
2541 struct RT {
2542 char A;
2543 int B[10][20];
2544 char C;
2545 };
2546 struct ST {
2547 int X;
2548 double Y;
2549 struct RT Z;
2550 };
2551
2552 int *foo(struct ST *s) {
2553 return &amp;s[1].Z.B[5][13];
2554 }
2555</pre>
2556
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2557<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2558
2559<pre>
2560 %RT = type { sbyte, [10 x [20 x int]], sbyte }
2561 %ST = type { int, double, %RT }
2562
Brian Gaeke7283e7c2004-07-02 21:08:14 +0000[diff] [blame]2563 implementation
2564
2565 int* %foo(%ST* %s) {
2566 entry:
2567 %reg = getelementptr %ST* %s, int 1, uint 2, uint 1, int 5, int 13
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2568 ret int* %reg
2569 }
2570</pre>
2571
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2572<h5>Semantics:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2573
2574<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2575on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2576and <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]2577<a href="#t_integer">integer</a> type but the value will always be sign extended
2578to 64-bits. <a href="#t_struct">Structure</a> types, require <tt>uint</tt>
2579<b>constants</b>.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2580
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2581<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2582type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ int, double, %RT
2583}</tt>' type, a structure. The second index indexes into the third element of
2584the structure, yielding a '<tt>%RT</tt>' = '<tt>{ sbyte, [10 x [20 x int]],
2585sbyte }</tt>' type, another structure. The third index indexes into the second
2586element of the structure, yielding a '<tt>[10 x [20 x int]]</tt>' type, an
2587array. The two dimensions of the array are subscripted into, yielding an
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2588'<tt>int</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2589to this element, thus computing a value of '<tt>int*</tt>' type.</p>
2590
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2591<p>Note that it is perfectly legal to index partially through a
2592structure, returning a pointer to an inner element. Because of this,
2593the LLVM code for the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2594
2595<pre>
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]2596 int* %foo(%ST* %s) {
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2597 %t1 = getelementptr %ST* %s, int 1 <i>; yields %ST*:%t1</i>
2598 %t2 = getelementptr %ST* %t1, int 0, uint 2 <i>; yields %RT*:%t2</i>
2599 %t3 = getelementptr %RT* %t2, int 0, uint 1 <i>; yields [10 x [20 x int]]*:%t3</i>
2600 %t4 = getelementptr [10 x [20 x int]]* %t3, int 0, int 5 <i>; yields [20 x int]*:%t4</i>
2601 %t5 = getelementptr [20 x int]* %t4, int 0, int 13 <i>; yields int*:%t5</i>
2602 ret int* %t5
2603 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2604</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2605
2606<p>Note that it is undefined to access an array out of bounds: array and
2607pointer indexes must always be within the defined bounds of the array type.
2608The one exception for this rules is zero length arrays. These arrays are
2609defined to be accessible as variable length arrays, which requires access
2610beyond the zero'th element.</p>
2611
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2612<p>The getelementptr instruction is often confusing. For some more insight
2613into how it works, see <a href="GetElementPtr.html">the getelementptr
2614FAQ</a>.</p>
2615
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2616<h5>Example:</h5>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2617
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2618<pre>
2619 <i>; yields [12 x ubyte]*:aptr</i>
2620 %aptr = getelementptr {int, [12 x ubyte]}* %sptr, long 0, uint 1
2621</pre>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2622</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2623
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2624<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]2625<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2626</div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2627<div class="doc_text">
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]2628<p>The instructions in this category are the conversion instructions (casting)
2629which all take a single operand and a type. They perform various bit conversions
2630on the operand.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2631</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2632
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2633<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2634<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2635 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
2636</div>
2637<div class="doc_text">
2638
2639<h5>Syntax:</h5>
2640<pre>
2641 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2642</pre>
2643
2644<h5>Overview:</h5>
2645<p>
2646The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
2647</p>
2648
2649<h5>Arguments:</h5>
2650<p>
2651The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
2652be an <a href="#t_integer">integer</a> type, and a type that specifies the size
2653and type of the result, which must be an <a href="#t_integral">integral</a>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2654type. The bit size of <tt>value</tt> must be larger than the bit size of
2655<tt>ty2</tt>. Equal sized types are not allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2656
2657<h5>Semantics:</h5>
2658<p>
2659The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2660and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
2661larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
2662It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2663
2664<h5>Example:</h5>
2665<pre>
2666 %X = trunc int 257 to ubyte <i>; yields ubyte:1</i>
2667 %Y = trunc int 123 to bool <i>; yields bool:true</i>
2668</pre>
2669</div>
2670
2671<!-- _______________________________________________________________________ -->
2672<div class="doc_subsubsection">
2673 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
2674</div>
2675<div class="doc_text">
2676
2677<h5>Syntax:</h5>
2678<pre>
2679 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2680</pre>
2681
2682<h5>Overview:</h5>
2683<p>The '<tt>zext</tt>' instruction zero extends its operand to type
2684<tt>ty2</tt>.</p>
2685
2686
2687<h5>Arguments:</h5>
2688<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
2689<a href="#t_integral">integral</a> type, and a type to cast it to, which must
2690also be of <a href="#t_integral">integral</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2691<tt>value</tt> must be smaller than the bit size of the destination type,
2692<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2693
2694<h5>Semantics:</h5>
2695<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
2696bits until it reaches the size of the destination type, <tt>ty2</tt>. When the
2697the operand and the type are the same size, no bit filling is done and the
2698cast is considered a <i>no-op cast</i> because no bits change (only the type
2699changes).</p>
2700
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2701<p>When zero extending from bool, the result will alwasy be either 0 or 1.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2702
2703<h5>Example:</h5>
2704<pre>
2705 %X = zext int 257 to ulong <i>; yields ulong:257</i>
2706 %Y = zext bool true to int <i>; yields int:1</i>
2707</pre>
2708</div>
2709
2710<!-- _______________________________________________________________________ -->
2711<div class="doc_subsubsection">
2712 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
2713</div>
2714<div class="doc_text">
2715
2716<h5>Syntax:</h5>
2717<pre>
2718 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2719</pre>
2720
2721<h5>Overview:</h5>
2722<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
2723
2724<h5>Arguments:</h5>
2725<p>
2726The '<tt>sext</tt>' instruction takes a value to cast, which must be of
2727<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]2728also be of <a href="#t_integral">integral</a> type. The bit size of the
2729<tt>value</tt> must be smaller than the bit size of the destination type,
2730<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2731
2732<h5>Semantics:</h5>
2733<p>
2734The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
2735bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
2736the type <tt>ty2</tt>. When the the operand and the type are the same size,
2737no bit filling is done and the cast is considered a <i>no-op cast</i> because
2738no bits change (only the type changes).</p>
2739
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2740<p>When sign extending from bool, the extension always results in -1 or 0.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2741
2742<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2743<pre>
2744 %X = sext sbyte -1 to ushort <i>; yields ushort:65535</i>
2745 %Y = sext bool true to int <i>; yields int:-1</i>
2746</pre>
2747</div>
2748
2749<!-- _______________________________________________________________________ -->
2750<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]2751 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
2752</div>
2753
2754<div class="doc_text">
2755
2756<h5>Syntax:</h5>
2757
2758<pre>
2759 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2760</pre>
2761
2762<h5>Overview:</h5>
2763<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
2764<tt>ty2</tt>.</p>
2765
2766
2767<h5>Arguments:</h5>
2768<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
2769 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
2770cast it to. The size of <tt>value</tt> must be larger than the size of
2771<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
2772<i>no-op cast</i>.</p>
2773
2774<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2775<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
2776<a href="#t_floating">floating point</a> type to a smaller
2777<a href="#t_floating">floating point</a> type. If the value cannot fit within
2778the destination type, <tt>ty2</tt>, then the results are undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]2779
2780<h5>Example:</h5>
2781<pre>
2782 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
2783 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
2784</pre>
2785</div>
2786
2787<!-- _______________________________________________________________________ -->
2788<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2789 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
2790</div>
2791<div class="doc_text">
2792
2793<h5>Syntax:</h5>
2794<pre>
2795 &lt;result&gt; = fpext &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>fpext</tt>' extends a floating point <tt>value</tt> to a larger
2800floating point value.</p>
2801
2802<h5>Arguments:</h5>
2803<p>The '<tt>fpext</tt>' instruction takes a
2804<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2805and a <a href="#t_floating">floating point</a> type to cast it to. The source
2806type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2807
2808<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2809<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
2810<a href="t_floating">floating point</a> type to a larger
2811<a href="t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
2812used to make a <i>no-op cast</i> because it always changes bits. Use
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2813<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]2814
2815<h5>Example:</h5>
2816<pre>
2817 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
2818 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
2819</pre>
2820</div>
2821
2822<!-- _______________________________________________________________________ -->
2823<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2824 <a name="i_fp2uint">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2825</div>
2826<div class="doc_text">
2827
2828<h5>Syntax:</h5>
2829<pre>
2830 &lt;result&gt; = fp2uint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2831</pre>
2832
2833<h5>Overview:</h5>
2834<p>The '<tt>fp2uint</tt>' converts a floating point <tt>value</tt> to its
2835unsigned integer equivalent of type <tt>ty2</tt>.
2836</p>
2837
2838<h5>Arguments:</h5>
2839<p>The '<tt>fp2uint</tt>' instruction takes a value to cast, which must be a
2840<a href="#t_floating">floating point</a> value, and a type to cast it to, which
2841must be an <a href="#t_integral">integral</a> type.</p>
2842
2843<h5>Semantics:</h5>
2844<p> The '<tt>fp2uint</tt>' instruction converts its
2845<a href="#t_floating">floating point</a> operand into the nearest (rounding
2846towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
2847the results are undefined.</p>
2848
2849<p>When converting to bool, the conversion is done as a comparison against
2850zero. If the <tt>value</tt> was zero, the bool result will be <tt>false</tt>.
2851If the <tt>value</tt> was non-zero, the bool result will be <tt>true</tt>.</p>
2852
2853<h5>Example:</h5>
2854<pre>
2855 %X = fp2uint double 123.0 to int <i>; yields int:123</i>
2856 %Y = fp2uint float 1.0E+300 to bool <i>; yields bool:true</i>
2857 %X = fp2uint float 1.04E+17 to ubyte <i>; yields undefined:1</i>
2858</pre>
2859</div>
2860
2861<!-- _______________________________________________________________________ -->
2862<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2863 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2864</div>
2865<div class="doc_text">
2866
2867<h5>Syntax:</h5>
2868<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2869 &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]2870</pre>
2871
2872<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2873<p>The '<tt>fptosi</tt>' instruction converts
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2874<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]2875</p>
2876
2877
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2878<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2879<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]2880<a href="#t_floating">floating point</a> value, and a type to cast it to, which
2881must also be an <a href="#t_integral">integral</a> type.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2882
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2883<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2884<p>The '<tt>fptosi</tt>' instruction converts its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2885<a href="#t_floating">floating point</a> operand into the nearest (rounding
2886towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
2887the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2888
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2889<p>When converting to bool, the conversion is done as a comparison against
2890zero. If the <tt>value</tt> was zero, the bool result will be <tt>false</tt>.
2891If the <tt>value</tt> was non-zero, the bool result will be <tt>true</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2892
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2893<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2894<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2895 %X = fptosi double -123.0 to int <i>; yields int:-123</i>
2896 %Y = fptosi float 1.0E-247 to bool <i>; yields bool:true</i>
2897 %X = fptosi float 1.04E+17 to sbyte <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2898</pre>
2899</div>
2900
2901<!-- _______________________________________________________________________ -->
2902<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2903 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2904</div>
2905<div class="doc_text">
2906
2907<h5>Syntax:</h5>
2908<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2909 &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]2910</pre>
2911
2912<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2913<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2914integer and converts that value to the <tt>ty2</tt> type.</p>
2915
2916
2917<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2918<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]2919<a href="#t_integral">integral</a> value, and a type to cast it to, which must
2920be a <a href="#t_floating">floating point</a> type.</p>
2921
2922<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2923<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2924integer quantity and converts it to the corresponding floating point value. If
2925the value cannot fit in the floating point value, the results are undefined.</p>
2926
2927
2928<h5>Example:</h5>
2929<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2930 %X = uitofp int 257 to float <i>; yields float:257.0</i>
2931 %Y = uitofp sbyte -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2932</pre>
2933</div>
2934
2935<!-- _______________________________________________________________________ -->
2936<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2937 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2938</div>
2939<div class="doc_text">
2940
2941<h5>Syntax:</h5>
2942<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2943 &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]2944</pre>
2945
2946<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2947<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2948integer and converts that value to the <tt>ty2</tt> type.</p>
2949
2950<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2951<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]2952<a href="#t_integral">integral</a> value, and a type to cast it to, which must be
2953a <a href="#t_floating">floating point</a> type.</p>
2954
2955<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2956<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2957integer quantity and converts it to the corresponding floating point value. If
2958the value cannot fit in the floating point value, the results are undefined.</p>
2959
2960<h5>Example:</h5>
2961<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2962 %X = sitofp int 257 to float <i>; yields float:257.0</i>
2963 %Y = sitofp sbyte -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2964</pre>
2965</div>
2966
2967<!-- _______________________________________________________________________ -->
2968<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]2969 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
2970</div>
2971<div class="doc_text">
2972
2973<h5>Syntax:</h5>
2974<pre>
2975 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2976</pre>
2977
2978<h5>Overview:</h5>
2979<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
2980the integer type <tt>ty2</tt>.</p>
2981
2982<h5>Arguments:</h5>
2983<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
2984must be a <a href="t_pointer">pointer</a> value, and a type to cast it to
2985<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
2986
2987<h5>Semantics:</h5>
2988<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
2989<tt>ty2</tt> by interpreting the pointer value as an integer and either
2990truncating or zero extending that value to the size of the integer type. If
2991<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
2992<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
2993are the same size, then nothing is done (<i>no-op cast</i>).</p>
2994
2995<h5>Example:</h5>
2996<pre>
2997 %X = ptrtoint int* %X to sbyte <i>; yields truncation on 32-bit</i>
2998 %Y = ptrtoint int* %x to ulong <i>; yields zero extend on 32-bit</i>
2999</pre>
3000</div>
3001
3002<!-- _______________________________________________________________________ -->
3003<div class="doc_subsubsection">
3004 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3005</div>
3006<div class="doc_text">
3007
3008<h5>Syntax:</h5>
3009<pre>
3010 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3011</pre>
3012
3013<h5>Overview:</h5>
3014<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3015a pointer type, <tt>ty2</tt>.</p>
3016
3017<h5>Arguments:</h5>
3018<p>The '<tt>inttoptr</tt>' instruction takes an <a href="i_integer">integer</a>
3019value to cast, and a type to cast it to, which must be a
3020<a href="#t_pointer">pointer</a> type. </tt>
3021
3022<h5>Semantics:</h5>
3023<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3024<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3025the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3026size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3027the size of a pointer then a zero extension is done. If they are the same size,
3028nothing is done (<i>no-op cast</i>).</p>
3029
3030<h5>Example:</h5>
3031<pre>
3032 %X = inttoptr int 255 to int* <i>; yields zero extend on 64-bit</i>
3033 %X = inttoptr int 255 to int* <i>; yields no-op on 32-bit </i>
3034 %Y = inttoptr short 0 to int* <i>; yields zero extend on 32-bit</i>
3035</pre>
3036</div>
3037
3038<!-- _______________________________________________________________________ -->
3039<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3040 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3041</div>
3042<div class="doc_text">
3043
3044<h5>Syntax:</h5>
3045<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3046 &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]3047</pre>
3048
3049<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3050<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3051<tt>ty2</tt> without changing any bits.</p>
3052
3053<h5>Arguments:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3054<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3055a first class value, and a type to cast it to, which must also be a <a
3056 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
3057and the destination type, <tt>ty2</tt>, must be identical.</p>
3058
3059<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3060<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3061<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3062this conversion. The conversion is done as if the <tt>value</tt> had been
3063stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3064converted to other pointer types with this instruction. To convert pointers to
3065other types, use the <a href="#i_inttoptr">inttoptr</a> or
3066<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3067
3068<h5>Example:</h5>
3069<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3070 %X = bitcast ubyte 255 to sbyte <i>; yields sbyte:-1</i>
3071 %Y = bitcast uint* %x to sint* <i>; yields sint*:%x</i>
3072 %Z = bitcast <2xint> %V to long; <i>; yields long: %V</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3073</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3074</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3075
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3076<!-- ======================================================================= -->
3077<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3078<div class="doc_text">
3079<p>The instructions in this category are the "miscellaneous"
3080instructions, which defy better classification.</p>
3081</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3082
3083<!-- _______________________________________________________________________ -->
3084<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3085</div>
3086<div class="doc_text">
3087<h5>Syntax:</h5>
3088<pre> &lt;result&gt; = icmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
3089</pre>
3090<h5>Overview:</h5>
3091<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
3092of its two integer operands.</p>
3093<h5>Arguments:</h5>
3094<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
3095the condition code which indicates the kind of comparison to perform. It is not
3096a value, just a keyword. The possibilities for the condition code are:
3097<ol>
3098 <li><tt>eq</tt>: equal</li>
3099 <li><tt>ne</tt>: not equal </li>
3100 <li><tt>ugt</tt>: unsigned greater than</li>
3101 <li><tt>uge</tt>: unsigned greater or equal</li>
3102 <li><tt>ult</tt>: unsigned less than</li>
3103 <li><tt>ule</tt>: unsigned less or equal</li>
3104 <li><tt>sgt</tt>: signed greater than</li>
3105 <li><tt>sge</tt>: signed greater or equal</li>
3106 <li><tt>slt</tt>: signed less than</li>
3107 <li><tt>sle</tt>: signed less or equal</li>
3108</ol>
3109<p>The remaining two arguments must be of <a href="#t_integral">integral</a>,
3110<a href="#t_pointer">pointer</a> or a <a href="#t_packed">packed</a> integral
3111type. They must have identical types.</p>
3112<h5>Semantics:</h5>
3113<p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3114the condition code given as <tt>cond</tt>. The comparison performed always
3115yields a <a href="#t_bool">bool</a> result, as follows:
3116<ol>
3117 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3118 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3119 </li>
3120 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3121 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3122 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3123 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3124 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3125 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3126 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3127 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3128 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3129 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3130 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3131 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3132 <li><tt>sge</tt>: interprets the operands as signed values and yields
3133 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3134 <li><tt>slt</tt>: interprets the operands as signed values and yields
3135 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3136 <li><tt>sle</tt>: interprets the operands as signed values and yields
3137 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3138 </li>
3139</ol>
3140<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
3141values are treated as integers and then compared.</p>
3142<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]3143the vector are compared in turn and the predicate must hold for all
3144elements.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3145
3146<h5>Example:</h5>
3147<pre> &lt;result&gt; = icmp eq int 4, 5 <i>; yields: result=false</i>
3148 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3149 &lt;result&gt; = icmp ult short 4, 5 <i>; yields: result=true</i>
3150 &lt;result&gt; = icmp sgt sbyte 4, 5 <i>; yields: result=false</i>
3151 &lt;result&gt; = icmp ule sbyte -4, 5 <i>; yields: result=false</i>
3152 &lt;result&gt; = icmp sge sbyte 4, 5 <i>; yields: result=false</i>
3153</pre>
3154</div>
3155
3156<!-- _______________________________________________________________________ -->
3157<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3158</div>
3159<div class="doc_text">
3160<h5>Syntax:</h5>
3161<pre> &lt;result&gt; = fcmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
3162</pre>
3163<h5>Overview:</h5>
3164<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3165of its floating point operands.</p>
3166<h5>Arguments:</h5>
3167<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
3168the condition code which indicates the kind of comparison to perform. It is not
3169a value, just a keyword. The possibilities for the condition code are:
3170<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3171 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3172 <li><tt>oeq</tt>: ordered and equal</li>
3173 <li><tt>ogt</tt>: ordered and greater than </li>
3174 <li><tt>oge</tt>: ordered and greater than or equal</li>
3175 <li><tt>olt</tt>: ordered and less than </li>
3176 <li><tt>ole</tt>: ordered and less than or equal</li>
3177 <li><tt>one</tt>: ordered and not equal</li>
3178 <li><tt>ord</tt>: ordered (no nans)</li>
3179 <li><tt>ueq</tt>: unordered or equal</li>
3180 <li><tt>ugt</tt>: unordered or greater than </li>
3181 <li><tt>uge</tt>: unordered or greater than or equal</li>
3182 <li><tt>ult</tt>: unordered or less than </li>
3183 <li><tt>ule</tt>: unordered or less than or equal</li>
3184 <li><tt>une</tt>: unordered or not equal</li>
3185 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3186 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3187</ol>
Reid Spencer93a49852006-12-06 07:08:07 +0000[diff] [blame]3188<p>In the preceding, <i>ordered</i> means that neither operand is a QNAN while
3189<i>unordered</i> means that either operand may be a QNAN.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3190<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be of
3191<a href="#t_floating">floating point</a>, or a <a href="#t_packed">packed</a>
3192floating point type. They must have identical types.</p>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3193<p>In the foregoing, <i>ordered</i> means that neither operand is a QNAN and
3194<i>unordered</i> means that either operand is a QNAN.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3195<h5>Semantics:</h5>
3196<p>The '<tt>fcmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3197the condition code given as <tt>cond</tt>. The comparison performed always
3198yields a <a href="#t_bool">bool</a> result, as follows:
3199<ol>
3200 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3201 <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]3202 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3203 <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]3204 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3205 <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]3206 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3207 <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]3208 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3209 <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]3210 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3211 <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]3212 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3213 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3214 <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]3215 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3216 <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]3217 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3218 <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]3219 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3220 <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]3221 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3222 <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]3223 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3224 <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]3225 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3226 <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]3227 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3228</ol>
3229<p>If the operands are <a href="#t_packed">packed</a> typed, the elements of
3230the vector are compared in turn and the predicate must hold for all elements.
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3231</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3232
3233<h5>Example:</h5>
3234<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3235 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3236 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3237 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3238</pre>
3239</div>
3240
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3241<!-- _______________________________________________________________________ -->
3242<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
3243Instruction</a> </div>
3244<div class="doc_text">
3245<h5>Syntax:</h5>
3246<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
3247<h5>Overview:</h5>
3248<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
3249the SSA graph representing the function.</p>
3250<h5>Arguments:</h5>
3251<p>The type of the incoming values are specified with the first type
3252field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
3253as arguments, with one pair for each predecessor basic block of the
3254current block. Only values of <a href="#t_firstclass">first class</a>
3255type may be used as the value arguments to the PHI node. Only labels
3256may be used as the label arguments.</p>
3257<p>There must be no non-phi instructions between the start of a basic
3258block and the PHI instructions: i.e. PHI instructions must be first in
3259a basic block.</p>
3260<h5>Semantics:</h5>
3261<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the
3262value specified by the parameter, depending on which basic block we
3263came from in the last <a href="#terminators">terminator</a> instruction.</p>
3264<h5>Example:</h5>
3265<pre>Loop: ; Infinite loop that counts from 0 on up...<br> %indvar = phi uint [ 0, %LoopHeader ], [ %nextindvar, %Loop ]<br> %nextindvar = add uint %indvar, 1<br> br label %Loop<br></pre>
3266</div>
3267
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3268<!-- _______________________________________________________________________ -->
3269<div class="doc_subsubsection">
3270 <a name="i_select">'<tt>select</tt>' Instruction</a>
3271</div>
3272
3273<div class="doc_text">
3274
3275<h5>Syntax:</h5>
3276
3277<pre>
3278 &lt;result&gt; = select bool &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
3279</pre>
3280
3281<h5>Overview:</h5>
3282
3283<p>
3284The '<tt>select</tt>' instruction is used to choose one value based on a
3285condition, without branching.
3286</p>
3287
3288
3289<h5>Arguments:</h5>
3290
3291<p>
3292The '<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.
3293</p>
3294
3295<h5>Semantics:</h5>
3296
3297<p>
3298If the boolean condition evaluates to true, the instruction returns the first
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3299value argument; otherwise, it returns the second value argument.
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3300</p>
3301
3302<h5>Example:</h5>
3303
3304<pre>
3305 %X = select bool true, ubyte 17, ubyte 42 <i>; yields ubyte:17</i>
3306</pre>
3307</div>
3308
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]3309
3310<!-- _______________________________________________________________________ -->
3311<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3312 <a name="i_call">'<tt>call</tt>' Instruction</a>
3313</div>
3314
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3315<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3316
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3317<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3318<pre>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3319 &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]3320</pre>
3321
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3322<h5>Overview:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3323
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3324<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3325
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3326<h5>Arguments:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3327
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3328<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3329
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3330<ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3331 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3332 <p>The optional "tail" marker indicates whether the callee function accesses
3333 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3334 function call is eligible for tail call optimization. Note that calls may
3335 be marked "tail" even if they do not occur before a <a
3336 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3337 </li>
3338 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3339 <p>The optional "cconv" marker indicates which <a href="callingconv">calling
3340 convention</a> the call should use. If none is specified, the call defaults
3341 to using C calling conventions.
3342 </li>
3343 <li>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3344 <p>'<tt>ty</tt>': shall be the signature of the pointer to function value
3345 being invoked. The argument types must match the types implied by this
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3346 signature. This type can be omitted if the function is not varargs and
3347 if the function type does not return a pointer to a function.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3348 </li>
3349 <li>
3350 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
3351 be invoked. In most cases, this is a direct function invocation, but
3352 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3353 to function value.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3354 </li>
3355 <li>
3356 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencera7e302a2005-05-01 22:22:57 +0000[diff] [blame]3357 function signature argument types. All arguments must be of
3358 <a href="#t_firstclass">first class</a> type. If the function signature
3359 indicates the function accepts a variable number of arguments, the extra
3360 arguments can be specified.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3361 </li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3362</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3363
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3364<h5>Semantics:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3365
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3366<p>The '<tt>call</tt>' instruction is used to cause control flow to
3367transfer to a specified function, with its incoming arguments bound to
3368the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
3369instruction in the called function, control flow continues with the
3370instruction after the function call, and the return value of the
3371function is bound to the result argument. This is a simpler case of
3372the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3373
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3374<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3375
3376<pre>
3377 %retval = call int %test(int %argc)
3378 call int(sbyte*, ...) *%printf(sbyte* %msg, int 12, sbyte 42);
3379 %X = tail call int %foo()
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3380 %Y = tail call <a href="#callingconv">fastcc</a> int %foo()
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3381</pre>
3382
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3383</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3384
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3385<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3386<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3387 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3388</div>
3389
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3390<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3391
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3392<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3393
3394<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3395 &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]3396</pre>
3397
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3398<h5>Overview:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3399
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3400<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3401the "variable argument" area of a function call. It is used to implement the
3402<tt>va_arg</tt> macro in C.</p>
3403
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3404<h5>Arguments:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3405
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3406<p>This instruction takes a <tt>va_list*</tt> value and the type of
3407the argument. It returns a value of the specified argument type and
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]3408increments the <tt>va_list</tt> to point to the next argument. Again, the
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3409actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3410
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3411<h5>Semantics:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3412
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3413<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
3414type from the specified <tt>va_list</tt> and causes the
3415<tt>va_list</tt> to point to the next argument. For more information,
3416see the variable argument handling <a href="#int_varargs">Intrinsic
3417Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3418
3419<p>It is legal for this instruction to be called in a function which does not
3420take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3421function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3422
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3423<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3424href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3425argument.</p>
3426
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3427<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3428
3429<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
3430
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3431</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3432
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3433<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3434<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
3435<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3436
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3437<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3438
3439<p>LLVM supports the notion of an "intrinsic function". These functions have
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3440well known names and semantics and are required to follow certain
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3441restrictions. Overall, these instructions represent an extension mechanism for
3442the LLVM language that does not require changing all of the transformations in
3443LLVM to add to the language (or the bytecode reader/writer, the parser,
3444etc...).</p>
3445
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3446<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
3447prefix is reserved in LLVM for intrinsic names; thus, functions may not be named
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3448this. Intrinsic functions must always be external functions: you cannot define
3449the body of intrinsic functions. Intrinsic functions may only be used in call
3450or invoke instructions: it is illegal to take the address of an intrinsic
3451function. Additionally, because intrinsic functions are part of the LLVM
3452language, it is required that they all be documented here if any are added.</p>
3453
3454
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3455<p>To learn how to add an intrinsic function, please see the <a
Chris Lattner590cff32005-05-11 03:35:57 +0000[diff] [blame]3456href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3457</p>
3458
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3459</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3460
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3461<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3462<div class="doc_subsection">
3463 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
3464</div>
3465
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3466<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3467
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3468<p>Variable argument support is defined in LLVM with the <a
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3469 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3470intrinsic functions. These functions are related to the similarly
3471named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3472
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3473<p>All of these functions operate on arguments that use a
3474target-specific value type "<tt>va_list</tt>". The LLVM assembly
3475language reference manual does not define what this type is, so all
3476transformations should be prepared to handle intrinsics with any type
3477used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3478
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]3479<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]3480instruction and the variable argument handling intrinsic functions are
3481used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3482
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3483<pre>
3484int %test(int %X, ...) {
3485 ; Initialize variable argument processing
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3486 %ap = alloca sbyte*
3487 call void %<a href="#i_va_start">llvm.va_start</a>(sbyte** %ap)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3488
3489 ; Read a single integer argument
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3490 %tmp = va_arg sbyte** %ap, int
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3491
3492 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3493 %aq = alloca sbyte*
Andrew Lenharthd0a4c622005-06-22 20:38:11 +0000[diff] [blame]3494 call void %<a href="#i_va_copy">llvm.va_copy</a>(sbyte** %aq, sbyte** %ap)
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3495 call void %<a href="#i_va_end">llvm.va_end</a>(sbyte** %aq)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3496
3497 ; Stop processing of arguments.
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3498 call void %<a href="#i_va_end">llvm.va_end</a>(sbyte** %ap)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3499 ret int %tmp
3500}
3501</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3502</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3503
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3504<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3505<div class="doc_subsubsection">
3506 <a name="i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
3507</div>
3508
3509
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3510<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3511<h5>Syntax:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3512<pre> declare void %llvm.va_start(&lt;va_list&gt;* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3513<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3514<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
3515<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
3516href="#i_va_arg">va_arg</a></tt>.</p>
3517
3518<h5>Arguments:</h5>
3519
3520<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
3521
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3522<h5>Semantics:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3523
3524<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
3525macro available in C. In a target-dependent way, it initializes the
3526<tt>va_list</tt> element the argument points to, so that the next call to
3527<tt>va_arg</tt> will produce the first variable argument passed to the function.
3528Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
3529last argument of the function, the compiler can figure that out.</p>
3530
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3531</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3532
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3533<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3534<div class="doc_subsubsection">
3535 <a name="i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
3536</div>
3537
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3538<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3539<h5>Syntax:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3540<pre> declare void %llvm.va_end(&lt;va_list*&gt; &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3541<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3542<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>&lt;arglist&gt;</tt>
3543which has been initialized previously with <tt><a href="#i_va_start">llvm.va_start</a></tt>
3544or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3545<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3546<p>The argument is a <tt>va_list</tt> to destroy.</p>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3547<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3548<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]3549macro available in C. In a target-dependent way, it destroys the <tt>va_list</tt>.
3550Calls to <a href="#i_va_start"><tt>llvm.va_start</tt></a> and <a
3551 href="#i_va_copy"><tt>llvm.va_copy</tt></a> must be matched exactly
3552with calls to <tt>llvm.va_end</tt>.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3553</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3554
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3555<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3556<div class="doc_subsubsection">
3557 <a name="i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
3558</div>
3559
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3560<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3561
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3562<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3563
3564<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3565 declare void %llvm.va_copy(&lt;va_list&gt;* &lt;destarglist&gt;,
Andrew Lenharthd0a4c622005-06-22 20:38:11 +0000[diff] [blame]3566 &lt;va_list&gt;* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3567</pre>
3568
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3569<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3570
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3571<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position from
3572the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3573
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3574<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3575
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3576<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]3577The 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]3578
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3579
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3580<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3581
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3582<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt> macro
3583available in C. In a target-dependent way, it copies the source
3584<tt>va_list</tt> element into the destination list. This intrinsic is necessary
3585because 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]3586arbitrarily complex and require memory allocation, for example.</p>
3587
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3588</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3589
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3590<!-- ======================================================================= -->
3591<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3592 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
3593</div>
3594
3595<div class="doc_text">
3596
3597<p>
3598LLVM support for <a href="GarbageCollection.html">Accurate Garbage
3599Collection</a> requires the implementation and generation of these intrinsics.
3600These intrinsics allow identification of <a href="#i_gcroot">GC roots on the
3601stack</a>, as well as garbage collector implementations that require <a
3602href="#i_gcread">read</a> and <a href="#i_gcwrite">write</a> barriers.
3603Front-ends for type-safe garbage collected languages should generate these
3604intrinsics to make use of the LLVM garbage collectors. For more details, see <a
3605href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
3606</p>
3607</div>
3608
3609<!-- _______________________________________________________________________ -->
3610<div class="doc_subsubsection">
3611 <a name="i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
3612</div>
3613
3614<div class="doc_text">
3615
3616<h5>Syntax:</h5>
3617
3618<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]3619 declare void %llvm.gcroot(&lt;ty&gt;** %ptrloc, &lt;ty2&gt;* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3620</pre>
3621
3622<h5>Overview:</h5>
3623
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]3624<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]3625the code generator, and allows some metadata to be associated with it.</p>
3626
3627<h5>Arguments:</h5>
3628
3629<p>The first argument specifies the address of a stack object that contains the
3630root pointer. The second pointer (which must be either a constant or a global
3631value address) contains the meta-data to be associated with the root.</p>
3632
3633<h5>Semantics:</h5>
3634
3635<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
3636location. At compile-time, the code generator generates information to allow
3637the runtime to find the pointer at GC safe points.
3638</p>
3639
3640</div>
3641
3642
3643<!-- _______________________________________________________________________ -->
3644<div class="doc_subsubsection">
3645 <a name="i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
3646</div>
3647
3648<div class="doc_text">
3649
3650<h5>Syntax:</h5>
3651
3652<pre>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3653 declare sbyte* %llvm.gcread(sbyte* %ObjPtr, sbyte** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3654</pre>
3655
3656<h5>Overview:</h5>
3657
3658<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
3659locations, allowing garbage collector implementations that require read
3660barriers.</p>
3661
3662<h5>Arguments:</h5>
3663
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3664<p>The second argument is the address to read from, which should be an address
3665allocated from the garbage collector. The first object is a pointer to the
3666start of the referenced object, if needed by the language runtime (otherwise
3667null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3668
3669<h5>Semantics:</h5>
3670
3671<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
3672instruction, but may be replaced with substantially more complex code by the
3673garbage collector runtime, as needed.</p>
3674
3675</div>
3676
3677
3678<!-- _______________________________________________________________________ -->
3679<div class="doc_subsubsection">
3680 <a name="i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
3681</div>
3682
3683<div class="doc_text">
3684
3685<h5>Syntax:</h5>
3686
3687<pre>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3688 declare void %llvm.gcwrite(sbyte* %P1, sbyte* %Obj, sbyte** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3689</pre>
3690
3691<h5>Overview:</h5>
3692
3693<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
3694locations, allowing garbage collector implementations that require write
3695barriers (such as generational or reference counting collectors).</p>
3696
3697<h5>Arguments:</h5>
3698
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3699<p>The first argument is the reference to store, the second is the start of the
3700object to store it to, and the third is the address of the field of Obj to
3701store to. If the runtime does not require a pointer to the object, Obj may be
3702null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3703
3704<h5>Semantics:</h5>
3705
3706<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
3707instruction, but may be replaced with substantially more complex code by the
3708garbage collector runtime, as needed.</p>
3709
3710</div>
3711
3712
3713
3714<!-- ======================================================================= -->
3715<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3716 <a name="int_codegen">Code Generator Intrinsics</a>
3717</div>
3718
3719<div class="doc_text">
3720<p>
3721These intrinsics are provided by LLVM to expose special features that may only
3722be implemented with code generator support.
3723</p>
3724
3725</div>
3726
3727<!-- _______________________________________________________________________ -->
3728<div class="doc_subsubsection">
3729 <a name="i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
3730</div>
3731
3732<div class="doc_text">
3733
3734<h5>Syntax:</h5>
3735<pre>
Chris Lattnerfcf39d42006-01-13 01:20:27 +0000[diff] [blame]3736 declare sbyte *%llvm.returnaddress(uint &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3737</pre>
3738
3739<h5>Overview:</h5>
3740
3741<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]3742The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
3743target-specific value indicating the return address of the current function
3744or one of its callers.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3745</p>
3746
3747<h5>Arguments:</h5>
3748
3749<p>
3750The argument to this intrinsic indicates which function to return the address
3751for. Zero indicates the calling function, one indicates its caller, etc. The
3752argument is <b>required</b> to be a constant integer value.
3753</p>
3754
3755<h5>Semantics:</h5>
3756
3757<p>
3758The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
3759the return address of the specified call frame, or zero if it cannot be
3760identified. The value returned by this intrinsic is likely to be incorrect or 0
3761for arguments other than zero, so it should only be used for debugging purposes.
3762</p>
3763
3764<p>
3765Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]3766aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3767source-language caller.
3768</p>
3769</div>
3770
3771
3772<!-- _______________________________________________________________________ -->
3773<div class="doc_subsubsection">
3774 <a name="i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
3775</div>
3776
3777<div class="doc_text">
3778
3779<h5>Syntax:</h5>
3780<pre>
Chris Lattnerfcf39d42006-01-13 01:20:27 +0000[diff] [blame]3781 declare sbyte *%llvm.frameaddress(uint &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.frameaddress</tt>' intrinsic attempts to return the
3788target-specific frame pointer value for the specified stack frame.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3789</p>
3790
3791<h5>Arguments:</h5>
3792
3793<p>
3794The argument to this intrinsic indicates which function to return the frame
3795pointer for. Zero indicates the calling function, one indicates its caller,
3796etc. The argument is <b>required</b> to be a constant integer value.
3797</p>
3798
3799<h5>Semantics:</h5>
3800
3801<p>
3802The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
3803the frame address of the specified call frame, or zero if it cannot be
3804identified. The value returned by this intrinsic is likely to be incorrect or 0
3805for arguments other than zero, so it should only be used for debugging purposes.
3806</p>
3807
3808<p>
3809Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]3810aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3811source-language caller.
3812</p>
3813</div>
3814
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3815<!-- _______________________________________________________________________ -->
3816<div class="doc_subsubsection">
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]3817 <a name="i_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
3818</div>
3819
3820<div class="doc_text">
3821
3822<h5>Syntax:</h5>
3823<pre>
3824 declare sbyte *%llvm.stacksave()
3825</pre>
3826
3827<h5>Overview:</h5>
3828
3829<p>
3830The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
3831the function stack, for use with <a href="#i_stackrestore">
3832<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
3833features like scoped automatic variable sized arrays in C99.
3834</p>
3835
3836<h5>Semantics:</h5>
3837
3838<p>
3839This intrinsic returns a opaque pointer value that can be passed to <a
3840href="#i_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
3841<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
3842<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
3843state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
3844practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
3845that were allocated after the <tt>llvm.stacksave</tt> was executed.
3846</p>
3847
3848</div>
3849
3850<!-- _______________________________________________________________________ -->
3851<div class="doc_subsubsection">
3852 <a name="i_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
3853</div>
3854
3855<div class="doc_text">
3856
3857<h5>Syntax:</h5>
3858<pre>
3859 declare void %llvm.stackrestore(sbyte* %ptr)
3860</pre>
3861
3862<h5>Overview:</h5>
3863
3864<p>
3865The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
3866the function stack to the state it was in when the corresponding <a
3867href="#llvm.stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
3868useful for implementing language features like scoped automatic variable sized
3869arrays in C99.
3870</p>
3871
3872<h5>Semantics:</h5>
3873
3874<p>
3875See the description for <a href="#i_stacksave"><tt>llvm.stacksave</tt></a>.
3876</p>
3877
3878</div>
3879
3880
3881<!-- _______________________________________________________________________ -->
3882<div class="doc_subsubsection">
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3883 <a name="i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
3884</div>
3885
3886<div class="doc_text">
3887
3888<h5>Syntax:</h5>
3889<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]3890 declare void %llvm.prefetch(sbyte * &lt;address&gt;,
3891 uint &lt;rw&gt;, uint &lt;locality&gt;)
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3892</pre>
3893
3894<h5>Overview:</h5>
3895
3896
3897<p>
3898The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3899a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
3900no
3901effect on the behavior of the program but can change its performance
Chris Lattner2a615362005-02-28 19:47:14 +0000[diff] [blame]3902characteristics.
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3903</p>
3904
3905<h5>Arguments:</h5>
3906
3907<p>
3908<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
3909determining if the fetch should be for a read (0) or write (1), and
3910<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattneraeffb4a2005-03-07 20:31:38 +0000[diff] [blame]3911locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3912<tt>locality</tt> arguments must be constant integers.
3913</p>
3914
3915<h5>Semantics:</h5>
3916
3917<p>
3918This intrinsic does not modify the behavior of the program. In particular,
3919prefetches cannot trap and do not produce a value. On targets that support this
3920intrinsic, the prefetch can provide hints to the processor cache for better
3921performance.
3922</p>
3923
3924</div>
3925
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]3926<!-- _______________________________________________________________________ -->
3927<div class="doc_subsubsection">
3928 <a name="i_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
3929</div>
3930
3931<div class="doc_text">
3932
3933<h5>Syntax:</h5>
3934<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]3935 declare void %llvm.pcmarker( uint &lt;id&gt; )
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]3936</pre>
3937
3938<h5>Overview:</h5>
3939
3940
3941<p>
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3942The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
3943(PC) in a region of
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]3944code to simulators and other tools. The method is target specific, but it is
3945expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]3946The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnerd07c3f42005-11-15 06:07:55 +0000[diff] [blame]3947after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb3e7afd2006-03-24 07:16:10 +0000[diff] [blame]3948optimizations. The intended use is to be inserted after optimizations to allow
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3949correlations of simulation runs.
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]3950</p>
3951
3952<h5>Arguments:</h5>
3953
3954<p>
3955<tt>id</tt> is a numerical id identifying the marker.
3956</p>
3957
3958<h5>Semantics:</h5>
3959
3960<p>
3961This intrinsic does not modify the behavior of the program. Backends that do not
3962support this intrinisic may ignore it.
3963</p>
3964
3965</div>
3966
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]3967<!-- _______________________________________________________________________ -->
3968<div class="doc_subsubsection">
3969 <a name="i_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
3970</div>
3971
3972<div class="doc_text">
3973
3974<h5>Syntax:</h5>
3975<pre>
3976 declare ulong %llvm.readcyclecounter( )
3977</pre>
3978
3979<h5>Overview:</h5>
3980
3981
3982<p>
3983The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
3984counter register (or similar low latency, high accuracy clocks) on those targets
3985that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
3986As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
3987should only be used for small timings.
3988</p>
3989
3990<h5>Semantics:</h5>
3991
3992<p>
3993When directly supported, reading the cycle counter should not modify any memory.
3994Implementations are allowed to either return a application specific value or a
3995system wide value. On backends without support, this is lowered to a constant 0.
3996</p>
3997
3998</div>
3999
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4000<!-- ======================================================================= -->
4001<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4002 <a name="int_libc">Standard C Library Intrinsics</a>
4003</div>
4004
4005<div class="doc_text">
4006<p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4007LLVM provides intrinsics for a few important standard C library functions.
4008These intrinsics allow source-language front-ends to pass information about the
4009alignment of the pointer arguments to the code generator, providing opportunity
4010for more efficient code generation.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4011</p>
4012
4013</div>
4014
4015<!-- _______________________________________________________________________ -->
4016<div class="doc_subsubsection">
4017 <a name="i_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
4018</div>
4019
4020<div class="doc_text">
4021
4022<h5>Syntax:</h5>
4023<pre>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4024 declare void %llvm.memcpy.i32(sbyte* &lt;dest&gt;, sbyte* &lt;src&gt;,
4025 uint &lt;len&gt;, uint &lt;align&gt;)
4026 declare void %llvm.memcpy.i64(sbyte* &lt;dest&gt;, sbyte* &lt;src&gt;,
4027 ulong &lt;len&gt;, uint &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4028</pre>
4029
4030<h5>Overview:</h5>
4031
4032<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4033The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4034location to the destination location.
4035</p>
4036
4037<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4038Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4039intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4040</p>
4041
4042<h5>Arguments:</h5>
4043
4044<p>
4045The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4046the source. The third argument is an integer argument
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4047specifying the number of bytes to copy, and the fourth argument is the alignment
4048of the source and destination locations.
4049</p>
4050
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4051<p>
4052If 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]4053the caller guarantees that both the source and destination pointers are aligned
4054to that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4055</p>
4056
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4057<h5>Semantics:</h5>
4058
4059<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4060The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4061location to the destination location, which are not allowed to overlap. It
4062copies "len" bytes of memory over. If the argument is known to be aligned to
4063some boundary, this can be specified as the fourth argument, otherwise it should
4064be set to 0 or 1.
4065</p>
4066</div>
4067
4068
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4069<!-- _______________________________________________________________________ -->
4070<div class="doc_subsubsection">
4071 <a name="i_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
4072</div>
4073
4074<div class="doc_text">
4075
4076<h5>Syntax:</h5>
4077<pre>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4078 declare void %llvm.memmove.i32(sbyte* &lt;dest&gt;, sbyte* &lt;src&gt;,
4079 uint &lt;len&gt;, uint &lt;align&gt;)
4080 declare void %llvm.memmove.i64(sbyte* &lt;dest&gt;, sbyte* &lt;src&gt;,
4081 ulong &lt;len&gt;, uint &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4082</pre>
4083
4084<h5>Overview:</h5>
4085
4086<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4087The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
4088location to the destination location. It is similar to the
4089'<tt>llvm.memcmp</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4090</p>
4091
4092<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4093Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
4094intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4095</p>
4096
4097<h5>Arguments:</h5>
4098
4099<p>
4100The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4101the source. The third argument is an integer argument
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4102specifying the number of bytes to copy, and the fourth argument is the alignment
4103of the source and destination locations.
4104</p>
4105
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4106<p>
4107If 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]4108the caller guarantees that the source and destination pointers are aligned to
4109that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4110</p>
4111
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4112<h5>Semantics:</h5>
4113
4114<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4115The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4116location to the destination location, which may overlap. It
4117copies "len" bytes of memory over. If the argument is known to be aligned to
4118some boundary, this can be specified as the fourth argument, otherwise it should
4119be set to 0 or 1.
4120</p>
4121</div>
4122
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4123
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4124<!-- _______________________________________________________________________ -->
4125<div class="doc_subsubsection">
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4126 <a name="i_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4127</div>
4128
4129<div class="doc_text">
4130
4131<h5>Syntax:</h5>
4132<pre>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4133 declare void %llvm.memset.i32(sbyte* &lt;dest&gt;, ubyte &lt;val&gt;,
4134 uint &lt;len&gt;, uint &lt;align&gt;)
4135 declare void %llvm.memset.i64(sbyte* &lt;dest&gt;, ubyte &lt;val&gt;,
4136 ulong &lt;len&gt;, uint &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4137</pre>
4138
4139<h5>Overview:</h5>
4140
4141<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4142The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4143byte value.
4144</p>
4145
4146<p>
4147Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
4148does not return a value, and takes an extra alignment argument.
4149</p>
4150
4151<h5>Arguments:</h5>
4152
4153<p>
4154The first argument is a pointer to the destination to fill, the second is the
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4155byte value to fill it with, the third argument is an integer
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4156argument specifying the number of bytes to fill, and the fourth argument is the
4157known alignment of destination location.
4158</p>
4159
4160<p>
4161If 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]4162the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4163</p>
4164
4165<h5>Semantics:</h5>
4166
4167<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4168The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
4169the
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4170destination location. If the argument is known to be aligned to some boundary,
4171this can be specified as the fourth argument, otherwise it should be set to 0 or
41721.
4173</p>
4174</div>
4175
4176
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4177<!-- _______________________________________________________________________ -->
4178<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4179 <a name="i_isunordered">'<tt>llvm.isunordered.*</tt>' Intrinsic</a>
Alkis Evlogimenos26bbe932004-06-13 01:16:15 +0000[diff] [blame]4180</div>
4181
4182<div class="doc_text">
4183
4184<h5>Syntax:</h5>
4185<pre>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4186 declare bool %llvm.isunordered.f32(float Val1, float Val2)
4187 declare bool %llvm.isunordered.f64(double Val1, double Val2)
Alkis Evlogimenos26bbe932004-06-13 01:16:15 +0000[diff] [blame]4188</pre>
4189
4190<h5>Overview:</h5>
4191
4192<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4193The '<tt>llvm.isunordered</tt>' intrinsics return true if either or both of the
Alkis Evlogimenos26bbe932004-06-13 01:16:15 +0000[diff] [blame]4194specified floating point values is a NAN.
4195</p>
4196
4197<h5>Arguments:</h5>
4198
4199<p>
4200The arguments are floating point numbers of the same type.
4201</p>
4202
4203<h5>Semantics:</h5>
4204
4205<p>
4206If either or both of the arguments is a SNAN or QNAN, it returns true, otherwise
4207false.
4208</p>
4209</div>
4210
4211
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4212<!-- _______________________________________________________________________ -->
4213<div class="doc_subsubsection">
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4214 <a name="i_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4215</div>
4216
4217<div class="doc_text">
4218
4219<h5>Syntax:</h5>
4220<pre>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4221 declare float %llvm.sqrt.f32(float %Val)
4222 declare double %llvm.sqrt.f64(double %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4223</pre>
4224
4225<h5>Overview:</h5>
4226
4227<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4228The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4229returning the same value as the libm '<tt>sqrt</tt>' function would. Unlike
4230<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
4231negative numbers (which allows for better optimization).
4232</p>
4233
4234<h5>Arguments:</h5>
4235
4236<p>
4237The argument and return value are floating point numbers of the same type.
4238</p>
4239
4240<h5>Semantics:</h5>
4241
4242<p>
4243This function returns the sqrt of the specified operand if it is a positive
4244floating point number.
4245</p>
4246</div>
4247
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4248<!-- _______________________________________________________________________ -->
4249<div class="doc_subsubsection">
4250 <a name="i_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
4251</div>
4252
4253<div class="doc_text">
4254
4255<h5>Syntax:</h5>
4256<pre>
4257 declare float %llvm.powi.f32(float %Val, int %power)
4258 declare double %llvm.powi.f64(double %Val, int %power)
4259</pre>
4260
4261<h5>Overview:</h5>
4262
4263<p>
4264The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
4265specified (positive or negative) power. The order of evaluation of
4266multiplications is not defined.
4267</p>
4268
4269<h5>Arguments:</h5>
4270
4271<p>
4272The second argument is an integer power, and the first is a value to raise to
4273that power.
4274</p>
4275
4276<h5>Semantics:</h5>
4277
4278<p>
4279This function returns the first value raised to the second power with an
4280unspecified sequence of rounding operations.</p>
4281</div>
4282
4283
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4284<!-- ======================================================================= -->
4285<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4286 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4287</div>
4288
4289<div class="doc_text">
4290<p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4291LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4292These allow efficient code generation for some algorithms.
4293</p>
4294
4295</div>
4296
4297<!-- _______________________________________________________________________ -->
4298<div class="doc_subsubsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4299 <a name="i_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
4300</div>
4301
4302<div class="doc_text">
4303
4304<h5>Syntax:</h5>
4305<pre>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4306 declare ushort %llvm.bswap.i16(ushort &lt;id&gt;)
4307 declare uint %llvm.bswap.i32(uint &lt;id&gt;)
4308 declare ulong %llvm.bswap.i64(ulong &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4309</pre>
4310
4311<h5>Overview:</h5>
4312
4313<p>
4314The '<tt>llvm.bwsap</tt>' family of intrinsics is used to byteswap a 16, 32 or
431564 bit quantity. These are useful for performing operations on data that is not
4316in the target's native byte order.
4317</p>
4318
4319<h5>Semantics:</h5>
4320
4321<p>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4322The <tt>llvm.bswap.16</tt> intrinsic returns a ushort value that has the high and low
4323byte of the input ushort swapped. Similarly, the <tt>llvm.bswap.i32</tt> intrinsic
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4324returns a uint value that has the four bytes of the input uint swapped, so that
4325if the input bytes are numbered 0, 1, 2, 3 then the returned uint will have its
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4326bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i64</tt> intrinsic extends this concept
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4327to 64 bits.
4328</p>
4329
4330</div>
4331
4332<!-- _______________________________________________________________________ -->
4333<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4334 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4335</div>
4336
4337<div class="doc_text">
4338
4339<h5>Syntax:</h5>
4340<pre>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4341 declare ubyte %llvm.ctpop.i8 (ubyte &lt;src&gt;)
4342 declare ushort %llvm.ctpop.i16(ushort &lt;src&gt;)
4343 declare uint %llvm.ctpop.i32(uint &lt;src&gt;)
4344 declare ulong %llvm.ctpop.i64(ulong &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4345</pre>
4346
4347<h5>Overview:</h5>
4348
4349<p>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4350The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
4351value.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4352</p>
4353
4354<h5>Arguments:</h5>
4355
4356<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]4357The only argument is the value to be counted. The argument may be of any
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4358unsigned integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4359</p>
4360
4361<h5>Semantics:</h5>
4362
4363<p>
4364The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
4365</p>
4366</div>
4367
4368<!-- _______________________________________________________________________ -->
4369<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]4370 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4371</div>
4372
4373<div class="doc_text">
4374
4375<h5>Syntax:</h5>
4376<pre>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4377 declare ubyte %llvm.ctlz.i8 (ubyte &lt;src&gt;)
4378 declare ushort %llvm.ctlz.i16(ushort &lt;src&gt;)
4379 declare uint %llvm.ctlz.i32(uint &lt;src&gt;)
4380 declare ulong %llvm.ctlz.i64(ulong &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4381</pre>
4382
4383<h5>Overview:</h5>
4384
4385<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4386The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
4387leading zeros in a variable.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4388</p>
4389
4390<h5>Arguments:</h5>
4391
4392<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]4393The only argument is the value to be counted. The argument may be of any
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4394unsigned integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4395</p>
4396
4397<h5>Semantics:</h5>
4398
4399<p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4400The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
4401in a variable. If the src == 0 then the result is the size in bits of the type
Chris Lattner99d3c272006-04-21 21:37:40 +0000[diff] [blame]4402of src. For example, <tt>llvm.ctlz(int 2) = 30</tt>.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4403</p>
4404</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4405
4406
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4407
4408<!-- _______________________________________________________________________ -->
4409<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]4410 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4411</div>
4412
4413<div class="doc_text">
4414
4415<h5>Syntax:</h5>
4416<pre>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4417 declare ubyte %llvm.cttz.i8 (ubyte &lt;src&gt;)
4418 declare ushort %llvm.cttz.i16(ushort &lt;src&gt;)
4419 declare uint %llvm.cttz.i32(uint &lt;src&gt;)
4420 declare ulong %llvm.cttz.i64(ulong &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4421</pre>
4422
4423<h5>Overview:</h5>
4424
4425<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4426The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
4427trailing zeros.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4428</p>
4429
4430<h5>Arguments:</h5>
4431
4432<p>
4433The only argument is the value to be counted. The argument may be of any
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4434unsigned integer type. The return type must match the argument type.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4435</p>
4436
4437<h5>Semantics:</h5>
4438
4439<p>
4440The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
4441in a variable. If the src == 0 then the result is the size in bits of the type
4442of src. For example, <tt>llvm.cttz(2) = 1</tt>.
4443</p>
4444</div>
4445
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4446<!-- ======================================================================= -->
4447<div class="doc_subsection">
4448 <a name="int_debugger">Debugger Intrinsics</a>
4449</div>
4450
4451<div class="doc_text">
4452<p>
4453The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
4454are described in the <a
4455href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
4456Debugging</a> document.
4457</p>
4458</div>
4459
4460
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4461<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4462<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]4463<address>
4464 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
4465 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
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4467 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!" /></a>
4468
4469 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]4470 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]4471 Last modified: $Date$
4472</address>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4473</body>
4474</html>