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gerrit-public.fairphone.software / toolchain / llvm-project / b25806fa5fb7aa0f79e2e6ff416941867ba4a354 / . / llvm / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
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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 Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]14
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]15<div class="doc_title"> LLVM Language Reference Manual </div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman76307852003-11-08 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 Lattner6af02f32004-12-09 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 Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a></li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]24 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]25 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]26 <li><a href="#functionstructure">Functions</a></li>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]27 <li><a href="#paramattrs">Parameter Attributes</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]28 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]29 <li><a href="#datalayout">Data Layout</a></li>
Reid Spencer15316f92007-03-28 02:46:29 +0000[diff] [blame]30 <li><a href="#checkpoint">Check Points</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]31 </ol>
32 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]33 <li><a href="#typesystem">Type System</a>
34 <ol>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]35 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]36 <ol>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]37 <li><a href="#t_classifications">Type Classifications</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]38 </ol>
39 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]40 <li><a href="#t_derived">Derived Types</a>
41 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]42 <li><a href="#t_array">Array Type</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]43 <li><a href="#t_function">Function Type</a></li>
44 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]45 <li><a href="#t_struct">Structure Type</a></li>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]46 <li><a href="#t_pstruct">Packed Structure Type</a></li>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]47 <li><a href="#t_vector">Vector Type</a></li>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]48 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]49 </ol>
50 </li>
51 </ol>
52 </li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]53 <li><a href="#constants">Constants</a>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]54 <ol>
55 <li><a href="#simpleconstants">Simple Constants</a>
56 <li><a href="#aggregateconstants">Aggregate Constants</a>
57 <li><a href="#globalconstants">Global Variable and Function Addresses</a>
58 <li><a href="#undefvalues">Undefined Values</a>
59 <li><a href="#constantexprs">Constant Expressions</a>
60 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]61 </li>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]62 <li><a href="#othervalues">Other Values</a>
63 <ol>
64 <li><a href="#inlineasm">Inline Assembler Expressions</a>
65 </ol>
66 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]67 <li><a href="#instref">Instruction Reference</a>
68 <ol>
69 <li><a href="#terminators">Terminator Instructions</a>
70 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]71 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
72 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]73 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
74 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]75 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]76 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]77 </ol>
78 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]79 <li><a href="#binaryops">Binary Operations</a>
80 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]81 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
82 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
83 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]84 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
85 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
86 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]87 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
88 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
89 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]90 </ol>
91 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]92 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
93 <ol>
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]94 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
95 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
96 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]97 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]98 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]99 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]100 </ol>
101 </li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]102 <li><a href="#vectorops">Vector Operations</a>
103 <ol>
104 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
105 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
106 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]107 </ol>
108 </li>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]109 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]110 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]111 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
112 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
113 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]114 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
115 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
116 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]117 </ol>
118 </li>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]119 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]120 <ol>
121 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
122 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
123 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
124 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
125 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]126 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
127 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
128 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
129 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]130 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
131 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]132 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]133 </ol>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]134 <li><a href="#otherops">Other Operations</a>
135 <ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]136 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
137 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]138 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]139 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]140 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]141 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]142 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]143 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]144 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]145 </li>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]146 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]147 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]148 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
149 <ol>
150 <li><a href="#i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
151 <li><a href="#i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
152 <li><a href="#i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
153 </ol>
154 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]155 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
156 <ol>
157 <li><a href="#i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
158 <li><a href="#i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
159 <li><a href="#i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
160 </ol>
161 </li>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]162 <li><a href="#int_codegen">Code Generator Intrinsics</a>
163 <ol>
164 <li><a href="#i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
165 <li><a href="#i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]166 <li><a href="#i_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
167 <li><a href="#i_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]168 <li><a href="#i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]169 <li><a href="#i_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]170 <li><a href="#i_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]171 </ol>
172 </li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]173 <li><a href="#int_libc">Standard C Library Intrinsics</a>
174 <ol>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]175 <li><a href="#i_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
176 <li><a href="#i_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
177 <li><a href="#i_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
Chris Lattner069b5bd2006-01-16 22:38:59 +0000[diff] [blame]178 <li><a href="#i_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]179 <li><a href="#i_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]180 </ol>
181 </li>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]182 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]183 <ol>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]184 <li><a href="#i_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]185 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
186 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
187 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]188 </ol>
189 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]190 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]191 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]192 </ol>
193 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]194</ol>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]195
196<div class="doc_author">
197 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
198 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]199</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]200
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]201<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]202<div class="doc_section"> <a name="abstract">Abstract </a></div>
203<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]204
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]205<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]206<p>This document is a reference manual for the LLVM assembly language.
207LLVM is an SSA based representation that provides type safety,
208low-level operations, flexibility, and the capability of representing
209'all' high-level languages cleanly. It is the common code
210representation used throughout all phases of the LLVM compilation
211strategy.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]212</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]213
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]214<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]215<div class="doc_section"> <a name="introduction">Introduction</a> </div>
216<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]217
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]218<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]219
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]220<p>The LLVM code representation is designed to be used in three
221different forms: as an in-memory compiler IR, as an on-disk bytecode
222representation (suitable for fast loading by a Just-In-Time compiler),
223and as a human readable assembly language representation. This allows
224LLVM to provide a powerful intermediate representation for efficient
225compiler transformations and analysis, while providing a natural means
226to debug and visualize the transformations. The three different forms
227of LLVM are all equivalent. This document describes the human readable
228representation and notation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]229
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]230<p>The LLVM representation aims to be light-weight and low-level
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]231while being expressive, typed, and extensible at the same time. It
232aims to be a "universal IR" of sorts, by being at a low enough level
233that high-level ideas may be cleanly mapped to it (similar to how
234microprocessors are "universal IR's", allowing many source languages to
235be mapped to them). By providing type information, LLVM can be used as
236the target of optimizations: for example, through pointer analysis, it
237can be proven that a C automatic variable is never accessed outside of
238the current function... allowing it to be promoted to a simple SSA
239value instead of a memory location.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]240
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]241</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]242
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]243<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]244<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]245
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]246<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]247
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]248<p>It is important to note that this document describes 'well formed'
249LLVM assembly language. There is a difference between what the parser
250accepts and what is considered 'well formed'. For example, the
251following instruction is syntactically okay, but not well formed:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]252
253<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]254 %x = <a href="#i_add">add</a> i32 1, %x
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]255</pre>
256
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]257<p>...because the definition of <tt>%x</tt> does not dominate all of
258its uses. The LLVM infrastructure provides a verification pass that may
259be used to verify that an LLVM module is well formed. This pass is
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]260automatically run by the parser after parsing input assembly and by
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]261the optimizer before it outputs bytecode. The violations pointed out
262by the verifier pass indicate bugs in transformation passes or input to
263the parser.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]264
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]265<!-- Describe the typesetting conventions here. --> </div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]266
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]267<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]268<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]269<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]270
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]271<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]272
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]273<p>LLVM uses three different forms of identifiers, for different
274purposes:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]275
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]276<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]277 <li>Named values are represented as a string of characters with a '%' prefix.
278 For example, %foo, %DivisionByZero, %a.really.long.identifier. The actual
279 regular expression used is '<tt>%[a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
280 Identifiers which require other characters in their names can be surrounded
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]281 with quotes. In this way, anything except a <tt>&quot;</tt> character can be used
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]282 in a name.</li>
283
284 <li>Unnamed values are represented as an unsigned numeric value with a '%'
285 prefix. For example, %12, %2, %44.</li>
286
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]287 <li>Constants, which are described in a <a href="#constants">section about
288 constants</a>, below.</li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]289</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]290
291<p>LLVM requires that values start with a '%' sign for two reasons: Compilers
292don't need to worry about name clashes with reserved words, and the set of
293reserved words may be expanded in the future without penalty. Additionally,
294unnamed identifiers allow a compiler to quickly come up with a temporary
295variable without having to avoid symbol table conflicts.</p>
296
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]297<p>Reserved words in LLVM are very similar to reserved words in other
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]298languages. There are keywords for different opcodes
299('<tt><a href="#i_add">add</a></tt>',
300 '<tt><a href="#i_bitcast">bitcast</a></tt>',
301 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]302href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]303and others. These reserved words cannot conflict with variable names, because
304none of them start with a '%' character.</p>
305
306<p>Here is an example of LLVM code to multiply the integer variable
307'<tt>%X</tt>' by 8:</p>
308
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]309<p>The easy way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]310
311<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]312 %result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]313</pre>
314
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]315<p>After strength reduction:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]316
317<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]318 %result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]319</pre>
320
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]321<p>And the hard way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]322
323<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]324 <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
325 <a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
326 %result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]327</pre>
328
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]329<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
330important lexical features of LLVM:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]331
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]332<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]333
334 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
335 line.</li>
336
337 <li>Unnamed temporaries are created when the result of a computation is not
338 assigned to a named value.</li>
339
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]340 <li>Unnamed temporaries are numbered sequentially</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]341
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]342</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]343
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]344<p>...and it also shows a convention that we follow in this document. When
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]345demonstrating instructions, we will follow an instruction with a comment that
346defines the type and name of value produced. Comments are shown in italic
347text.</p>
348
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]349</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]350
351<!-- *********************************************************************** -->
352<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
353<!-- *********************************************************************** -->
354
355<!-- ======================================================================= -->
356<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
357</div>
358
359<div class="doc_text">
360
361<p>LLVM programs are composed of "Module"s, each of which is a
362translation unit of the input programs. Each module consists of
363functions, global variables, and symbol table entries. Modules may be
364combined together with the LLVM linker, which merges function (and
365global variable) definitions, resolves forward declarations, and merges
366symbol table entries. Here is an example of the "hello world" module:</p>
367
368<pre><i>; Declare the string constant as a global constant...</i>
369<a href="#identifiers">%.LC0</a> = <a href="#linkage_internal">internal</a> <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]370 href="#globalvars">constant</a> <a href="#t_array">[13 x i8 ]</a> c"hello world\0A\00" <i>; [13 x i8 ]*</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]371
372<i>; External declaration of the puts function</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]373<a href="#functionstructure">declare</a> i32 %puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]374
375<i>; Definition of main function</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]376define i32 %main() { <i>; i32()* </i>
377 <i>; Convert [13x i8 ]* to i8 *...</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]378 %cast210 = <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]379 href="#i_getelementptr">getelementptr</a> [13 x i8 ]* %.LC0, i64 0, i64 0 <i>; i8 *</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]380
381 <i>; Call puts function to write out the string to stdout...</i>
382 <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]383 href="#i_call">call</a> i32 %puts(i8 * %cast210) <i>; i32</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]384 <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]385 href="#i_ret">ret</a> i32 0<br>}<br></pre>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]386
387<p>This example is made up of a <a href="#globalvars">global variable</a>
388named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
389function, and a <a href="#functionstructure">function definition</a>
390for "<tt>main</tt>".</p>
391
Chris Lattnerd79749a2004-12-09 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 Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]397
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]398</div>
399
400<!-- ======================================================================= -->
401<div class="doc_subsection">
402 <a name="linkage">Linkage Types</a>
403</div>
404
405<div class="doc_text">
406
407<p>
408All Global Variables and Functions have one of the following types of linkage:
409</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]410
411<dl>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]412
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]413 <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]414
415 <dd>Global values with internal linkage are only directly accessible by
416 objects in the current module. In particular, linking code into a module with
417 an internal global value may cause the internal to be renamed as necessary to
418 avoid collisions. Because the symbol is internal to the module, all
419 references can be updated. This corresponds to the notion of the
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]420 '<tt>static</tt>' keyword in C.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]421 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]422
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]423 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]424
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]425 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
426 the same name when linkage occurs. This is typically used to implement
427 inline functions, templates, or other code which must be generated in each
428 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
429 allowed to be discarded.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]430 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]431
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]432 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]433
434 <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage,
435 except that unreferenced <tt>weak</tt> globals may not be discarded. This is
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]436 used for globals that may be emitted in multiple translation units, but that
437 are not guaranteed to be emitted into every translation unit that uses them.
438 One example of this are common globals in C, such as "<tt>int X;</tt>" at
439 global scope.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]440 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]441
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]442 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]443
444 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
445 pointer to array type. When two global variables with appending linkage are
446 linked together, the two global arrays are appended together. This is the
447 LLVM, typesafe, equivalent of having the system linker append together
448 "sections" with identical names when .o files are linked.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]449 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]450
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]451 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
452 <dd>The semantics of this linkage follow the ELF model: the symbol is weak
453 until linked, if not linked, the symbol becomes null instead of being an
454 undefined reference.
455 </dd>
456</dl>
457
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]458 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]459
460 <dd>If none of the above identifiers are used, the global is externally
461 visible, meaning that it participates in linkage and can be used to resolve
462 external symbol references.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]463 </dd>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]464
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]465 <p>
466 The next two types of linkage are targeted for Microsoft Windows platform
467 only. They are designed to support importing (exporting) symbols from (to)
468 DLLs.
469 </p>
470
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]471 <dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]472 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
473
474 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
475 or variable via a global pointer to a pointer that is set up by the DLL
476 exporting the symbol. On Microsoft Windows targets, the pointer name is
477 formed by combining <code>_imp__</code> and the function or variable name.
478 </dd>
479
480 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
481
482 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
483 pointer to a pointer in a DLL, so that it can be referenced with the
484 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
485 name is formed by combining <code>_imp__</code> and the function or variable
486 name.
487 </dd>
488
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]489</dl>
490
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]491<p><a name="linkage_external"></a>For example, since the "<tt>.LC0</tt>"
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]492variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
493variable and was linked with this one, one of the two would be renamed,
494preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
495external (i.e., lacking any linkage declarations), they are accessible
Reid Spencer92c671e2007-01-05 00:59:10 +0000[diff] [blame]496outside of the current module.</p>
497<p>It is illegal for a function <i>declaration</i>
498to have any linkage type other than "externally visible", <tt>dllimport</tt>,
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]499or <tt>extern_weak</tt>.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]500
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]501</div>
502
503<!-- ======================================================================= -->
504<div class="doc_subsection">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]505 <a name="callingconv">Calling Conventions</a>
506</div>
507
508<div class="doc_text">
509
510<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
511and <a href="#i_invoke">invokes</a> can all have an optional calling convention
512specified for the call. The calling convention of any pair of dynamic
513caller/callee must match, or the behavior of the program is undefined. The
514following calling conventions are supported by LLVM, and more may be added in
515the future:</p>
516
517<dl>
518 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
519
520 <dd>This calling convention (the default if no other calling convention is
521 specified) matches the target C calling conventions. This calling convention
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]522 supports varargs function calls and tolerates some mismatch in the declared
Reid Spencer72ba4992006-12-31 21:30:18 +0000[diff] [blame]523 prototype and implemented declaration of the function (as does normal C).
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]524 </dd>
525
526 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
527
528 <dd>This calling convention attempts to make calls as fast as possible
529 (e.g. by passing things in registers). This calling convention allows the
530 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattnerc792eb32005-05-06 23:08:23 +0000[diff] [blame]531 without having to conform to an externally specified ABI. Implementations of
532 this convention should allow arbitrary tail call optimization to be supported.
533 This calling convention does not support varargs and requires the prototype of
534 all callees to exactly match the prototype of the function definition.
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]535 </dd>
536
537 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
538
539 <dd>This calling convention attempts to make code in the caller as efficient
540 as possible under the assumption that the call is not commonly executed. As
541 such, these calls often preserve all registers so that the call does not break
542 any live ranges in the caller side. This calling convention does not support
543 varargs and requires the prototype of all callees to exactly match the
544 prototype of the function definition.
545 </dd>
546
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]547 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]548
549 <dd>Any calling convention may be specified by number, allowing
550 target-specific calling conventions to be used. Target specific calling
551 conventions start at 64.
552 </dd>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]553</dl>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]554
555<p>More calling conventions can be added/defined on an as-needed basis, to
556support pascal conventions or any other well-known target-independent
557convention.</p>
558
559</div>
560
561<!-- ======================================================================= -->
562<div class="doc_subsection">
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]563 <a name="visibility">Visibility Styles</a>
564</div>
565
566<div class="doc_text">
567
568<p>
569All Global Variables and Functions have one of the following visibility styles:
570</p>
571
572<dl>
573 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
574
575 <dd>On ELF, default visibility means that the declaration is visible to other
576 modules and, in shared libraries, means that the declared entity may be
577 overridden. On Darwin, default visibility means that the declaration is
578 visible to other modules. Default visibility corresponds to "external
579 linkage" in the language.
580 </dd>
581
582 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
583
584 <dd>Two declarations of an object with hidden visibility refer to the same
585 object if they are in the same shared object. Usually, hidden visibility
586 indicates that the symbol will not be placed into the dynamic symbol table,
587 so no other module (executable or shared library) can reference it
588 directly.
589 </dd>
590
591</dl>
592
593</div>
594
595<!-- ======================================================================= -->
596<div class="doc_subsection">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]597 <a name="globalvars">Global Variables</a>
598</div>
599
600<div class="doc_text">
601
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]602<p>Global variables define regions of memory allocated at compilation time
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]603instead of run-time. Global variables may optionally be initialized, may have
604an explicit section to be placed in, and may
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]605have an optional explicit alignment specified. A
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]606variable may be defined as a global "constant," which indicates that the
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]607contents of the variable will <b>never</b> be modified (enabling better
608optimization, allowing the global data to be placed in the read-only section of
609an executable, etc). Note that variables that need runtime initialization
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]610cannot be marked "constant" as there is a store to the variable.</p>
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]611
612<p>
613LLVM explicitly allows <em>declarations</em> of global variables to be marked
614constant, even if the final definition of the global is not. This capability
615can be used to enable slightly better optimization of the program, but requires
616the language definition to guarantee that optimizations based on the
617'constantness' are valid for the translation units that do not include the
618definition.
619</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]620
621<p>As SSA values, global variables define pointer values that are in
622scope (i.e. they dominate) all basic blocks in the program. Global
623variables always define a pointer to their "content" type because they
624describe a region of memory, and all memory objects in LLVM are
625accessed through pointers.</p>
626
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]627<p>LLVM allows an explicit section to be specified for globals. If the target
628supports it, it will emit globals to the section specified.</p>
629
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]630<p>An explicit alignment may be specified for a global. If not present, or if
631the alignment is set to zero, the alignment of the global is set by the target
632to whatever it feels convenient. If an explicit alignment is specified, the
633global is forced to have at least that much alignment. All alignments must be
634a power of 2.</p>
635
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]636<p>For example, the following defines a global with an initializer, section,
637 and alignment:</p>
638
639<pre>
640 %G = constant float 1.0, section "foo", align 4
641</pre>
642
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]643</div>
644
645
646<!-- ======================================================================= -->
647<div class="doc_subsection">
648 <a name="functionstructure">Functions</a>
649</div>
650
651<div class="doc_text">
652
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]653<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
654an optional <a href="#linkage">linkage type</a>, an optional
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]655<a href="#visibility">visibility style</a>, an optional
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]656<a href="#callingconv">calling convention</a>, a return type, an optional
657<a href="#paramattrs">parameter attribute</a> for the return type, a function
658name, a (possibly empty) argument list (each with optional
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]659<a href="#paramattrs">parameter attributes</a>), an optional section, an
660optional alignment, an opening curly brace, a list of basic blocks, and a
661closing curly brace.
662
663LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
664optional <a href="#linkage">linkage type</a>, an optional
665<a href="#visibility">visibility style</a>, an optional
666<a href="#callingconv">calling convention</a>, a return type, an optional
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]667<a href="#paramattrs">parameter attribute</a> for the return type, a function
668name, a possibly empty list of arguments, and an optional alignment.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]669
670<p>A function definition contains a list of basic blocks, forming the CFG for
671the function. Each basic block may optionally start with a label (giving the
672basic block a symbol table entry), contains a list of instructions, and ends
673with a <a href="#terminators">terminator</a> instruction (such as a branch or
674function return).</p>
675
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]676<p>The first basic block in a program is special in two ways: it is immediately
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]677executed on entrance to the function, and it is not allowed to have predecessor
678basic blocks (i.e. there can not be any branches to the entry block of a
679function). Because the block can have no predecessors, it also cannot have any
680<a href="#i_phi">PHI nodes</a>.</p>
681
682<p>LLVM functions are identified by their name and type signature. Hence, two
683functions with the same name but different parameter lists or return values are
Chris Lattner455fc8c2005-03-07 22:13:59 +0000[diff] [blame]684considered different functions, and LLVM will resolve references to each
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]685appropriately.</p>
686
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]687<p>LLVM allows an explicit section to be specified for functions. If the target
688supports it, it will emit functions to the section specified.</p>
689
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]690<p>An explicit alignment may be specified for a function. If not present, or if
691the alignment is set to zero, the alignment of the function is set by the target
692to whatever it feels convenient. If an explicit alignment is specified, the
693function is forced to have at least that much alignment. All alignments must be
694a power of 2.</p>
695
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]696</div>
697
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]698<!-- ======================================================================= -->
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]699<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
700<div class="doc_text">
701 <p>The return type and each parameter of a function type may have a set of
702 <i>parameter attributes</i> associated with them. Parameter attributes are
703 used to communicate additional information about the result or parameters of
704 a function. Parameter attributes are considered to be part of the function
705 type so two functions types that differ only by the parameter attributes
706 are different function types.</p>
707
Reid Spencercf7ebf52007-01-15 18:27:39 +0000[diff] [blame]708 <p>Parameter attributes are simple keywords that follow the type specified. If
709 multiple parameter attributes are needed, they are space separated. For
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]710 example:</p><pre>
Reid Spencercf7ebf52007-01-15 18:27:39 +0000[diff] [blame]711 %someFunc = i16 (i8 sext %someParam) zext
712 %someFunc = i16 (i8 zext %someParam) zext</pre>
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]713 <p>Note that the two function types above are unique because the parameter has
Reid Spencercf7ebf52007-01-15 18:27:39 +0000[diff] [blame]714 a different attribute (sext in the first one, zext in the second). Also note
715 that the attribute for the function result (zext) comes immediately after the
716 argument list.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]717
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]718 <p>Currently, only the following parameter attributes are defined:</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]719 <dl>
Reid Spencercf7ebf52007-01-15 18:27:39 +0000[diff] [blame]720 <dt><tt>zext</tt></dt>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]721 <dd>This indicates that the parameter should be zero extended just before
722 a call to this function.</dd>
Reid Spencercf7ebf52007-01-15 18:27:39 +0000[diff] [blame]723 <dt><tt>sext</tt></dt>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]724 <dd>This indicates that the parameter should be sign extended just before
725 a call to this function.</dd>
Anton Korobeynikove8166852007-01-28 14:30:45 +0000[diff] [blame]726 <dt><tt>inreg</tt></dt>
727 <dd>This indicates that the parameter should be placed in register (if
Anton Korobeynikove93c6e82007-01-28 15:27:21 +0000[diff] [blame]728 possible) during assembling function call. Support for this attribute is
729 target-specific</dd>
Anton Korobeynikove8166852007-01-28 14:30:45 +0000[diff] [blame]730 <dt><tt>sret</tt></dt>
Anton Korobeynikove93c6e82007-01-28 15:27:21 +0000[diff] [blame]731 <dd>This indicates that the parameter specifies the address of a structure
Reid Spencer05dbb9d2007-03-22 02:02:11 +0000[diff] [blame]732 that is the return value of the function in the source program.</dd>
Reid Spencer9d1700e2007-03-22 02:18:56 +0000[diff] [blame]733 <dt><tt>noreturn</tt></dt>
734 <dd>This function attribute indicates that the function never returns. This
735 indicates to LLVM that every call to this function should be treated as if
736 an <tt>unreachable</tt> instruction immediately followed the call.</dd>
Reid Spencer05dbb9d2007-03-22 02:02:11 +0000[diff] [blame]737 <dt><tt>nounwind</tt></dt>
738 <dd>This function attribute indicates that the function type does not use
739 the unwind instruction and does not allow stack unwinding to propagate
740 through it.</dd>
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]741 </dl>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]742
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]743</div>
744
745<!-- ======================================================================= -->
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]746<div class="doc_subsection">
Chris Lattner93564892006-04-08 04:40:53 +0000[diff] [blame]747 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]748</div>
749
750<div class="doc_text">
751<p>
752Modules may contain "module-level inline asm" blocks, which corresponds to the
753GCC "file scope inline asm" blocks. These blocks are internally concatenated by
754LLVM and treated as a single unit, but may be separated in the .ll file if
755desired. The syntax is very simple:
756</p>
757
758<div class="doc_code"><pre>
Chris Lattnera1280ad2006-01-24 00:37:20 +0000[diff] [blame]759 module asm "inline asm code goes here"
760 module asm "more can go here"
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]761</pre></div>
762
763<p>The strings can contain any character by escaping non-printable characters.
764 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
765 for the number.
766</p>
767
768<p>
769 The inline asm code is simply printed to the machine code .s file when
770 assembly code is generated.
771</p>
772</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]773
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]774<!-- ======================================================================= -->
775<div class="doc_subsection">
776 <a name="datalayout">Data Layout</a>
777</div>
778
779<div class="doc_text">
780<p>A module may specify a target specific data layout string that specifies how
781data is to be laid out in memory. The syntax for the data layout is simply:<br/>
782<pre> target datalayout = "<i>layout specification</i>"
783</pre>
784The <i>layout specification</i> consists of a list of specifications separated
785by the minus sign character ('-'). Each specification starts with a letter
786and may include other information after the letter to define some aspect of the
787data layout. The specifications accepted are as follows: </p>
788<dl>
789 <dt><tt>E</tt></dt>
790 <dd>Specifies that the target lays out data in big-endian form. That is, the
791 bits with the most significance have the lowest address location.</dd>
792 <dt><tt>e</tt></dt>
793 <dd>Specifies that hte target lays out data in little-endian form. That is,
794 the bits with the least significance have the lowest address location.</dd>
795 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
796 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
797 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
798 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
799 too.</dd>
800 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
801 <dd>This specifies the alignment for an integer type of a given bit
802 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
803 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
804 <dd>This specifies the alignment for a vector type of a given bit
805 <i>size</i>.</dd>
806 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
807 <dd>This specifies the alignment for a floating point type of a given bit
808 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
809 (double).</dd>
810 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
811 <dd>This specifies the alignment for an aggregate type of a given bit
812 <i>size</i>.</dd>
813</dl>
814<p>When constructing the data layout for a given target, LLVM starts with a
815default set of specifications which are then (possibly) overriden by the
816specifications in the <tt>datalayout</tt> keyword. The default specifications
817are given in this list:</p>
818<ul>
819 <li><tt>E</tt> - big endian</li>
820 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
821 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
822 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
823 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
824 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
825 <li><tt>i64:32:64</tt> - i64 has abi alignment of 32-bits but preferred
826 alignment of 64-bits</li>
827 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
828 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
829 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
830 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
831 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
832</ul>
833<p>When llvm is determining the alignment for a given type, it uses the
834following rules:
835<ol>
836 <li>If the type sought is an exact match for one of the specifications, that
837 specification is used.</li>
838 <li>If no match is found, and the type sought is an integer type, then the
839 smallest integer type that is larger than the bitwidth of the sought type is
840 used. If none of the specifications are larger than the bitwidth then the the
841 largest integer type is used. For example, given the default specifications
842 above, the i7 type will use the alignment of i8 (next largest) while both
843 i65 and i256 will use the alignment of i64 (largest specified).</li>
844 <li>If no match is found, and the type sought is a vector type, then the
845 largest vector type that is smaller than the sought vector type will be used
846 as a fall back. This happens because <128 x double> can be implemented in
847 terms of 64 <2 x double>, for example.</li>
848</ol>
849</div>
Reid Spencer15316f92007-03-28 02:46:29 +0000[diff] [blame]850<!-- ======================================================================= -->
851<div class="doc_subsection">
852 <a name="datalayout">Data Layout</a>
853</div>
854<div class="doc_text">
855 <p>At the top level, the keyword <tt>checkpoint</tt> may be used to force the
856 assembler to check point the types and values it has defined so far. Any
857 unresolved types or references will generate error messages. This is useful
858 as an assertion point or for debugging.</p>
859</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]860
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]861<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]862<div class="doc_section"> <a name="typesystem">Type System</a> </div>
863<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]864
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]865<div class="doc_text">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]866
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]867<p>The LLVM type system is one of the most important features of the
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]868intermediate representation. Being typed enables a number of
869optimizations to be performed on the IR directly, without having to do
870extra analyses on the side before the transformation. A strong type
871system makes it easier to read the generated code and enables novel
872analyses and transformations that are not feasible to perform on normal
873three address code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]874
875</div>
876
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]877<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]878<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]879<div class="doc_text">
John Criswell417228d2004-04-09 16:48:45 +0000[diff] [blame]880<p>The primitive types are the fundamental building blocks of the LLVM
Chris Lattner455fc8c2005-03-07 22:13:59 +0000[diff] [blame]881system. The current set of primitive types is as follows:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]882
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]883<table class="layout">
884 <tr class="layout">
885 <td class="left">
886 <table>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]887 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]888 <tr><th>Type</th><th>Description</th></tr>
889 <tr><td><tt>void</tt></td><td>No value</td></tr>
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]890 <tr><td><tt>i8</tt></td><td>8-bit value</td></tr>
891 <tr><td><tt>i32</tt></td><td>32-bit value</td></tr>
Misha Brukman36c6bc12005-04-22 18:02:52 +0000[diff] [blame]892 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]893 <tr><td><tt>label</tt></td><td>Branch destination</td></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]894 </tbody>
895 </table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]896 </td>
897 <td class="right">
898 <table>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]899 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]900 <tr><th>Type</th><th>Description</th></tr>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]901 <tr><td><tt>i1</tt></td><td>True or False value</td></tr>
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]902 <tr><td><tt>i16</tt></td><td>16-bit value</td></tr>
903 <tr><td><tt>i64</tt></td><td>64-bit value</td></tr>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]904 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]905 </tbody>
906 </table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]907 </td>
908 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]909</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]910</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]911
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]912<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]913<div class="doc_subsubsection"> <a name="t_classifications">Type
914Classifications</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]915<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]916<p>These different primitive types fall into a few useful
917classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]918
919<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]920 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]921 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]922 <tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]923 <td><a name="t_integer">integer</a></td>
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]924 <td><tt>i1, i8, i16, i32, i64</tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]925 </tr>
926 <tr>
927 <td><a name="t_floating">floating point</a></td>
928 <td><tt>float, double</tt></td>
929 </tr>
930 <tr>
931 <td><a name="t_firstclass">first class</a></td>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]932 <td><tt>i1, i8, i16, i32, i64, float, double, <br/>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]933 <a href="#t_pointer">pointer</a>,<a href="#t_vector">vector</a></tt>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]934 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]935 </tr>
936 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]937</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]938
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]939<p>The <a href="#t_firstclass">first class</a> types are perhaps the
940most important. Values of these types are the only ones which can be
941produced by instructions, passed as arguments, or used as operands to
942instructions. This means that all structures and arrays must be
943manipulated either by pointer or by component.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]944</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]945
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]946<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]947<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]948
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]949<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]950
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]951<p>The real power in LLVM comes from the derived types in the system.
952This is what allows a programmer to represent arrays, functions,
953pointers, and other useful types. Note that these derived types may be
954recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]955
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]956</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]957
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]958<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]959<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]960
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]961<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]962
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]963<h5>Overview:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]964
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]965<p>The array type is a very simple derived type that arranges elements
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]966sequentially in memory. The array type requires a size (number of
967elements) and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]968
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]969<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]970
971<pre>
972 [&lt;# elements&gt; x &lt;elementtype&gt;]
973</pre>
974
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]975<p>The number of elements is a constant integer value; elementtype may
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]976be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]977
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]978<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]979<table class="layout">
980 <tr class="layout">
981 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]982 <tt>[40 x i32 ]</tt><br/>
983 <tt>[41 x i32 ]</tt><br/>
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]984 <tt>[40 x i8]</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]985 </td>
986 <td class="left">
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]987 Array of 40 32-bit integer values.<br/>
988 Array of 41 32-bit integer values.<br/>
989 Array of 40 8-bit integer values.<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]990 </td>
991 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]992</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]993<p>Here are some examples of multidimensional arrays:</p>
994<table class="layout">
995 <tr class="layout">
996 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]997 <tt>[3 x [4 x i32]]</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]998 <tt>[12 x [10 x float]]</tt><br/>
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]999 <tt>[2 x [3 x [4 x i16]]]</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1000 </td>
1001 <td class="left">
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1002 3x4 array of 32-bit integer values.<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1003 12x10 array of single precision floating point values.<br/>
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1004 2x3x4 array of 16-bit integer values.<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1005 </td>
1006 </tr>
1007</table>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1008
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1009<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1010length array. Normally, accesses past the end of an array are undefined in
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1011LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1012As a special case, however, zero length arrays are recognized to be variable
1013length. This allows implementation of 'pascal style arrays' with the LLVM
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1014type "{ i32, [0 x float]}", for example.</p>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1015
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1016</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1017
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1018<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1019<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1020<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1021<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1022<p>The function type can be thought of as a function signature. It
1023consists of a return type and a list of formal parameter types.
John Criswella0d50d22003-11-25 21:45:46 +0000[diff] [blame]1024Function types are usually used to build virtual function tables
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1025(which are structures of pointers to functions), for indirect function
1026calls, and when defining a function.</p>
John Criswella0d50d22003-11-25 21:45:46 +0000[diff] [blame]1027<p>
1028The return type of a function type cannot be an aggregate type.
1029</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1030<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1031<pre> &lt;returntype&gt; (&lt;parameter list&gt;)<br></pre>
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1032<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
Misha Brukman20f9a622004-08-12 20:16:08 +0000[diff] [blame]1033specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1034which indicates that the function takes a variable number of arguments.
1035Variable argument functions can access their arguments with the <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1036 href="#int_varargs">variable argument handling intrinsic</a> functions.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1037<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1038<table class="layout">
1039 <tr class="layout">
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1040 <td class="left"><tt>i32 (i32)</tt></td>
1041 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1042 </td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1043 </tr><tr class="layout">
Reid Spencere6a338d2007-01-15 18:28:34 +0000[diff] [blame]1044 <td class="left"><tt>float&nbsp;(i16&nbsp;sext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencer655dcc62006-12-31 07:20:23 +0000[diff] [blame]1045 </tt></td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1046 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1047 an <tt>i16</tt> that should be sign extended and a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1048 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1049 <tt>float</tt>.
1050 </td>
1051 </tr><tr class="layout">
1052 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1053 <td class="left">A vararg function that takes at least one
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1054 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1055 which returns an integer. This is the signature for <tt>printf</tt> in
1056 LLVM.
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1057 </td>
1058 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1059</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1060
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1061</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1062<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1063<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1064<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1065<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1066<p>The structure type is used to represent a collection of data members
1067together in memory. The packing of the field types is defined to match
1068the ABI of the underlying processor. The elements of a structure may
1069be any type that has a size.</p>
1070<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1071and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1072field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1073instruction.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1074<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1075<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1076<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1077<table class="layout">
1078 <tr class="layout">
1079 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1080 <tt>{ i32, i32, i32 }</tt><br/>
1081 <tt>{ float, i32 (i32) * }</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1082 </td>
1083 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1084 a triple of three <tt>i32</tt> values<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1085 A pair, where the first element is a <tt>float</tt> and the second element
1086 is a <a href="#t_pointer">pointer</a> to a <a href="#t_function">function</a>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1087 that takes an <tt>i32</tt>, returning an <tt>i32</tt>.<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1088 </td>
1089 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1090</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1091</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1092
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1093<!-- _______________________________________________________________________ -->
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1094<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1095</div>
1096<div class="doc_text">
1097<h5>Overview:</h5>
1098<p>The packed structure type is used to represent a collection of data members
1099together in memory. There is no padding between fields. Further, the alignment
1100of a packed structure is 1 byte. The elements of a packed structure may
1101be any type that has a size.</p>
1102<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1103and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1104field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1105instruction.</p>
1106<h5>Syntax:</h5>
1107<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1108<h5>Examples:</h5>
1109<table class="layout">
1110 <tr class="layout">
1111 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1112 <tt> &lt; { i32, i32, i32 } &gt; </tt><br/>
1113 <tt> &lt; { float, i32 (i32) * } &gt; </tt><br/>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1114 </td>
1115 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1116 a triple of three <tt>i32</tt> values<br/>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1117 A pair, where the first element is a <tt>float</tt> and the second element
1118 is a <a href="#t_pointer">pointer</a> to a <a href="#t_function">function</a>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1119 that takes an <tt>i32</tt>, returning an <tt>i32</tt>.<br/>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1120 </td>
1121 </tr>
1122</table>
1123</div>
1124
1125<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1126<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1127<div class="doc_text">
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1128<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1129<p>As in many languages, the pointer type represents a pointer or
1130reference to another object, which must live in memory.</p>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1131<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1132<pre> &lt;type&gt; *<br></pre>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1133<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1134<table class="layout">
1135 <tr class="layout">
1136 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1137 <tt>[4x i32]*</tt><br/>
1138 <tt>i32 (i32 *) *</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1139 </td>
1140 <td class="left">
1141 A <a href="#t_pointer">pointer</a> to <a href="#t_array">array</a> of
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1142 four <tt>i32</tt> values<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1143 A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1144 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
1145 <tt>i32</tt>.<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1146 </td>
1147 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1148</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1149</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1150
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1151<!-- _______________________________________________________________________ -->
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1152<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1153<div class="doc_text">
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1154
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1155<h5>Overview:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1156
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1157<p>A vector type is a simple derived type that represents a vector
1158of elements. Vector types are used when multiple primitive data
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1159are operated in parallel using a single instruction (SIMD).
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1160A vector type requires a size (number of
Chris Lattner330ce692005-11-10 01:44:22 +0000[diff] [blame]1161elements) and an underlying primitive data type. Vectors must have a power
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1162of two length (1, 2, 4, 8, 16 ...). Vector types are
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1163considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1164
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1165<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1166
1167<pre>
1168 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1169</pre>
1170
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1171<p>The number of elements is a constant integer value; elementtype may
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]1172be any integer or floating point type.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1173
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1174<h5>Examples:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1175
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1176<table class="layout">
1177 <tr class="layout">
1178 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1179 <tt>&lt;4 x i32&gt;</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1180 <tt>&lt;8 x float&gt;</tt><br/>
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1181 <tt>&lt;2 x i64&gt;</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1182 </td>
1183 <td class="left">
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1184 Vector of 4 32-bit integer values.<br/>
1185 Vector of 8 floating-point values.<br/>
1186 Vector of 2 64-bit integer values.<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1187 </td>
1188 </tr>
1189</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1190</div>
1191
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1192<!-- _______________________________________________________________________ -->
1193<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1194<div class="doc_text">
1195
1196<h5>Overview:</h5>
1197
1198<p>Opaque types are used to represent unknown types in the system. This
1199corresponds (for example) to the C notion of a foward declared structure type.
1200In LLVM, opaque types can eventually be resolved to any type (not just a
1201structure type).</p>
1202
1203<h5>Syntax:</h5>
1204
1205<pre>
1206 opaque
1207</pre>
1208
1209<h5>Examples:</h5>
1210
1211<table class="layout">
1212 <tr class="layout">
1213 <td class="left">
1214 <tt>opaque</tt>
1215 </td>
1216 <td class="left">
1217 An opaque type.<br/>
1218 </td>
1219 </tr>
1220</table>
1221</div>
1222
1223
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1224<!-- *********************************************************************** -->
1225<div class="doc_section"> <a name="constants">Constants</a> </div>
1226<!-- *********************************************************************** -->
1227
1228<div class="doc_text">
1229
1230<p>LLVM has several different basic types of constants. This section describes
1231them all and their syntax.</p>
1232
1233</div>
1234
1235<!-- ======================================================================= -->
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1236<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1237
1238<div class="doc_text">
1239
1240<dl>
1241 <dt><b>Boolean constants</b></dt>
1242
1243 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1244 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1245 </dd>
1246
1247 <dt><b>Integer constants</b></dt>
1248
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1249 <dd>Standard integers (such as '4') are constants of the <a
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1250 href="#t_integer">integer</a> type. Negative numbers may be used with
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1251 integer types.
1252 </dd>
1253
1254 <dt><b>Floating point constants</b></dt>
1255
1256 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1257 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1258 notation (see below). Floating point constants must have a <a
1259 href="#t_floating">floating point</a> type. </dd>
1260
1261 <dt><b>Null pointer constants</b></dt>
1262
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1263 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1264 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1265
1266</dl>
1267
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1268<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1269of floating point constants. For example, the form '<tt>double
12700x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
12714.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1272(and the only time that they are generated by the disassembler) is when a
1273floating point constant must be emitted but it cannot be represented as a
1274decimal floating point number. For example, NaN's, infinities, and other
1275special values are represented in their IEEE hexadecimal format so that
1276assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1277
1278</div>
1279
1280<!-- ======================================================================= -->
1281<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1282</div>
1283
1284<div class="doc_text">
Chris Lattner455fc8c2005-03-07 22:13:59 +0000[diff] [blame]1285<p>Aggregate constants arise from aggregation of simple constants
1286and smaller aggregate constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1287
1288<dl>
1289 <dt><b>Structure constants</b></dt>
1290
1291 <dd>Structure constants are represented with notation similar to structure
1292 type definitions (a comma separated list of elements, surrounded by braces
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1293 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* %G }</tt>",
1294 where "<tt>%G</tt>" is declared as "<tt>%G = external global i32</tt>". Structure constants
Chris Lattner455fc8c2005-03-07 22:13:59 +0000[diff] [blame]1295 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1296 types of elements must match those specified by the type.
1297 </dd>
1298
1299 <dt><b>Array constants</b></dt>
1300
1301 <dd>Array constants are represented with notation similar to array type
1302 definitions (a comma separated list of elements, surrounded by square brackets
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1303 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1304 constants must have <a href="#t_array">array type</a>, and the number and
1305 types of elements must match those specified by the type.
1306 </dd>
1307
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1308 <dt><b>Vector constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1309
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1310 <dd>Vector constants are represented with notation similar to vector type
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1311 definitions (a comma separated list of elements, surrounded by
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1312 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32 42,
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1313 i32 11, i32 74, i32 100 &gt;</tt>". VEctor constants must have <a
1314 href="#t_vector">vector type</a>, and the number and types of elements must
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1315 match those specified by the type.
1316 </dd>
1317
1318 <dt><b>Zero initialization</b></dt>
1319
1320 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1321 value to zero of <em>any</em> type, including scalar and aggregate types.
1322 This is often used to avoid having to print large zero initializers (e.g. for
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1323 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1324 initializers.
1325 </dd>
1326</dl>
1327
1328</div>
1329
1330<!-- ======================================================================= -->
1331<div class="doc_subsection">
1332 <a name="globalconstants">Global Variable and Function Addresses</a>
1333</div>
1334
1335<div class="doc_text">
1336
1337<p>The addresses of <a href="#globalvars">global variables</a> and <a
1338href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1339constants. These constants are explicitly referenced when the <a
1340href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1341href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1342file:</p>
1343
1344<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1345 %X = global i32 17
1346 %Y = global i32 42
1347 %Z = global [2 x i32*] [ i32* %X, i32* %Y ]
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1348</pre>
1349
1350</div>
1351
1352<!-- ======================================================================= -->
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1353<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1354<div class="doc_text">
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1355 <p>The string '<tt>undef</tt>' is recognized as a type-less constant that has
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1356 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1357 a constant is permitted.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1358
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1359 <p>Undefined values indicate to the compiler that the program is well defined
1360 no matter what value is used, giving the compiler more freedom to optimize.
1361 </p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1362</div>
1363
1364<!-- ======================================================================= -->
1365<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1366</div>
1367
1368<div class="doc_text">
1369
1370<p>Constant expressions are used to allow expressions involving other constants
1371to be used as constants. Constant expressions may be of any <a
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1372href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1373that does not have side effects (e.g. load and call are not supported). The
1374following is the syntax for constant expressions:</p>
1375
1376<dl>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1377 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1378 <dd>Truncate a constant to another type. The bit size of CST must be larger
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]1379 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1380
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1381 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1382 <dd>Zero extend a constant to another type. The bit size of CST must be
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]1383 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1384
1385 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1386 <dd>Sign extend a constant to another type. The bit size of CST must be
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]1387 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1388
1389 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1390 <dd>Truncate a floating point constant to another floating point type. The
1391 size of CST must be larger than the size of TYPE. Both types must be
1392 floating point.</dd>
1393
1394 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1395 <dd>Floating point extend a constant to another type. The size of CST must be
1396 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1397
1398 <dt><b><tt>fp2uint ( CST to TYPE )</tt></b></dt>
1399 <dd>Convert a floating point constant to the corresponding unsigned integer
1400 constant. TYPE must be an integer type. CST must be floating point. If the
1401 value won't fit in the integer type, the results are undefined.</dd>
1402
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]1403 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1404 <dd>Convert a floating point constant to the corresponding signed integer
1405 constant. TYPE must be an integer type. CST must be floating point. If the
1406 value won't fit in the integer type, the results are undefined.</dd>
1407
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]1408 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1409 <dd>Convert an unsigned integer constant to the corresponding floating point
1410 constant. TYPE must be floating point. CST must be of integer type. If the
1411 value won't fit in the floating point type, the results are undefined.</dd>
1412
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]1413 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1414 <dd>Convert a signed integer constant to the corresponding floating point
1415 constant. TYPE must be floating point. CST must be of integer type. If the
1416 value won't fit in the floating point type, the results are undefined.</dd>
1417
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]1418 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1419 <dd>Convert a pointer typed constant to the corresponding integer constant
1420 TYPE must be an integer type. CST must be of pointer type. The CST value is
1421 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1422
1423 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1424 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1425 pointer type. CST must be of integer type. The CST value is zero extended,
1426 truncated, or unchanged to make it fit in a pointer size. This one is
1427 <i>really</i> dangerous!</dd>
1428
1429 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1430 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1431 identical (same number of bits). The conversion is done as if the CST value
1432 was stored to memory and read back as TYPE. In other words, no bits change
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]1433 with this operator, just the type. This can be used for conversion of
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1434 vector types to any other type, as long as they have the same bit width. For
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]1435 pointers it is only valid to cast to another pointer type.
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1436 </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1437
1438 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1439
1440 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1441 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1442 instruction, the index list may have zero or more indexes, which are required
1443 to make sense for the type of "CSTPTR".</dd>
1444
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]1445 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1446
1447 <dd>Perform the <a href="#i_select">select operation</a> on
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1448 constants.</dd>
1449
1450 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1451 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1452
1453 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1454 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]1455
1456 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1457
1458 <dd>Perform the <a href="#i_extractelement">extractelement
1459 operation</a> on constants.
1460
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]1461 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1462
1463 <dd>Perform the <a href="#i_insertelement">insertelement
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1464 operation</a> on constants.</dd>
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]1465
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]1466
1467 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1468
1469 <dd>Perform the <a href="#i_shufflevector">shufflevector
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1470 operation</a> on constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]1471
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1472 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1473
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1474 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1475 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1476 binary</a> operations. The constraints on operands are the same as those for
1477 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1478 values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1479</dl>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1480</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]1481
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1482<!-- *********************************************************************** -->
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1483<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1484<!-- *********************************************************************** -->
1485
1486<!-- ======================================================================= -->
1487<div class="doc_subsection">
1488<a name="inlineasm">Inline Assembler Expressions</a>
1489</div>
1490
1491<div class="doc_text">
1492
1493<p>
1494LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1495Module-Level Inline Assembly</a>) through the use of a special value. This
1496value represents the inline assembler as a string (containing the instructions
1497to emit), a list of operand constraints (stored as a string), and a flag that
1498indicates whether or not the inline asm expression has side effects. An example
1499inline assembler expression is:
1500</p>
1501
1502<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1503 i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1504</pre>
1505
1506<p>
1507Inline assembler expressions may <b>only</b> be used as the callee operand of
1508a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1509</p>
1510
1511<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1512 %X = call i32 asm "<a href="#i_bswap">bswap</a> $0", "=r,r"(i32 %Y)
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1513</pre>
1514
1515<p>
1516Inline asms with side effects not visible in the constraint list must be marked
1517as having side effects. This is done through the use of the
1518'<tt>sideeffect</tt>' keyword, like so:
1519</p>
1520
1521<pre>
1522 call void asm sideeffect "eieio", ""()
1523</pre>
1524
1525<p>TODO: The format of the asm and constraints string still need to be
1526documented here. Constraints on what can be done (e.g. duplication, moving, etc
1527need to be documented).
1528</p>
1529
1530</div>
1531
1532<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1533<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1534<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1535
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1536<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1537
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1538<p>The LLVM instruction set consists of several different
1539classifications of instructions: <a href="#terminators">terminator
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1540instructions</a>, <a href="#binaryops">binary instructions</a>,
1541<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1542 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1543instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1544
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1545</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1546
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1547<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1548<div class="doc_subsection"> <a name="terminators">Terminator
1549Instructions</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1550
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1551<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1552
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1553<p>As mentioned <a href="#functionstructure">previously</a>, every
1554basic block in a program ends with a "Terminator" instruction, which
1555indicates which block should be executed after the current block is
1556finished. These terminator instructions typically yield a '<tt>void</tt>'
1557value: they produce control flow, not values (the one exception being
1558the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1559<p>There are six different terminator instructions: the '<a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1560 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1561instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1562the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1563 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1564 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1565
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1566</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1567
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1568<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1569<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1570Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1571<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1572<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1573<pre> ret &lt;type&gt; &lt;value&gt; <i>; Return a value from a non-void function</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1574 ret void <i>; Return from void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1575</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1576<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1577<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1578value) from a function back to the caller.</p>
John Criswell417228d2004-04-09 16:48:45 +0000[diff] [blame]1579<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1580returns a value and then causes control flow, and one that just causes
1581control flow to occur.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1582<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1583<p>The '<tt>ret</tt>' instruction may return any '<a
1584 href="#t_firstclass">first class</a>' type. Notice that a function is
1585not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
1586instruction inside of the function that returns a value that does not
1587match the return type of the function.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1588<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1589<p>When the '<tt>ret</tt>' instruction is executed, control flow
1590returns back to the calling function's context. If the caller is a "<a
John Criswell40db33f2004-06-25 15:16:57 +0000[diff] [blame]1591 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1592the instruction after the call. If the caller was an "<a
1593 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1594at the beginning of the "normal" destination block. If the instruction
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1595returns a value, that value shall set the call or invoke instruction's
1596return value.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1597<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1598<pre> ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1599 ret void <i>; Return from a void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1600</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1601</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1602<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1603<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1604<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1605<h5>Syntax:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1606<pre> br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1607</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1608<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1609<p>The '<tt>br</tt>' instruction is used to cause control flow to
1610transfer to a different basic block in the current function. There are
1611two forms of this instruction, corresponding to a conditional branch
1612and an unconditional branch.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1613<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1614<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1615single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1616unconditional form of the '<tt>br</tt>' instruction takes a single
1617'<tt>label</tt>' value as a target.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1618<h5>Semantics:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1619<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1620argument is evaluated. If the value is <tt>true</tt>, control flows
1621to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1622control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1623<h5>Example:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1624<pre>Test:<br> %cond = <a href="#i_icmp">icmp</a> eq, i32 %a, %b<br> br i1 %cond, label %IfEqual, label %IfUnequal<br>IfEqual:<br> <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1625 href="#i_ret">ret</a> i32 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> i32 0<br></pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1626</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1627<!-- _______________________________________________________________________ -->
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1628<div class="doc_subsubsection">
1629 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1630</div>
1631
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1632<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1633<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1634
1635<pre>
1636 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1637</pre>
1638
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1639<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1640
1641<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1642several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1643instruction, allowing a branch to occur to one of many possible
1644destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1645
1646
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1647<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1648
1649<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1650comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1651an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1652table is not allowed to contain duplicate constant entries.</p>
1653
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1654<h5>Semantics:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1655
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1656<p>The <tt>switch</tt> instruction specifies a table of values and
1657destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswellbcbb18c2004-06-25 16:05:06 +0000[diff] [blame]1658table is searched for the given value. If the value is found, control flow is
1659transfered to the corresponding destination; otherwise, control flow is
1660transfered to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1661
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1662<h5>Implementation:</h5>
1663
1664<p>Depending on properties of the target machine and the particular
1665<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswellbcbb18c2004-06-25 16:05:06 +0000[diff] [blame]1666ways. For example, it could be generated as a series of chained conditional
1667branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1668
1669<h5>Example:</h5>
1670
1671<pre>
1672 <i>; Emulate a conditional br instruction</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1673 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1674 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1675
1676 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1677 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1678
1679 <i>; Implement a jump table:</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1680 switch i32 %val, label %otherwise [ i32 0, label %onzero
1681 i32 1, label %onone
1682 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1683</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1684</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1685
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1686<!-- _______________________________________________________________________ -->
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1687<div class="doc_subsubsection">
1688 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1689</div>
1690
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1691<div class="doc_text">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1692
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1693<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1694
1695<pre>
1696 &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 Lattner6b7a0082006-05-14 18:23:06 +0000[diff] [blame]1697 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1698</pre>
1699
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]1700<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1701
1702<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1703function, with the possibility of control flow transfer to either the
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1704'<tt>normal</tt>' label or the
1705'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1706"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1707"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1708href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
1709continued at the dynamically nearest "exception" label.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1710
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1711<h5>Arguments:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1712
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1713<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1714
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1715<ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1716 <li>
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1717 The optional "cconv" marker indicates which <a href="callingconv">calling
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1718 convention</a> the call should use. If none is specified, the call defaults
1719 to using C calling conventions.
1720 </li>
1721 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1722 function value being invoked. In most cases, this is a direct function
1723 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1724 an arbitrary pointer to function value.
1725 </li>
1726
1727 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1728 function to be invoked. </li>
1729
1730 <li>'<tt>function args</tt>': argument list whose types match the function
1731 signature argument types. If the function signature indicates the function
1732 accepts a variable number of arguments, the extra arguments can be
1733 specified. </li>
1734
1735 <li>'<tt>normal label</tt>': the label reached when the called function
1736 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1737
1738 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1739 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1740
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1741</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1742
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1743<h5>Semantics:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1744
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1745<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1746href="#i_call">call</a></tt>' instruction in most regards. The primary
1747difference is that it establishes an association with a label, which is used by
1748the runtime library to unwind the stack.</p>
1749
1750<p>This instruction is used in languages with destructors to ensure that proper
1751cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1752exception. Additionally, this is important for implementation of
1753'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1754
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1755<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1756<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1757 %retval = invoke i32 %Test(i32 15) to label %Continue
1758 unwind label %TestCleanup <i>; {i32}:retval set</i>
1759 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Test(i32 15) to label %Continue
1760 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1761</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1762</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1763
1764
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1765<!-- _______________________________________________________________________ -->
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1766
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1767<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1768Instruction</a> </div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1769
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1770<div class="doc_text">
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1771
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1772<h5>Syntax:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1773<pre>
1774 unwind
1775</pre>
1776
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1777<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1778
1779<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
1780at the first callee in the dynamic call stack which used an <a
1781href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
1782primarily used to implement exception handling.</p>
1783
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1784<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1785
1786<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
1787immediately halt. The dynamic call stack is then searched for the first <a
1788href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
1789execution continues at the "exceptional" destination block specified by the
1790<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
1791dynamic call chain, undefined behavior results.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1792</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1793
1794<!-- _______________________________________________________________________ -->
1795
1796<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
1797Instruction</a> </div>
1798
1799<div class="doc_text">
1800
1801<h5>Syntax:</h5>
1802<pre>
1803 unreachable
1804</pre>
1805
1806<h5>Overview:</h5>
1807
1808<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
1809instruction is used to inform the optimizer that a particular portion of the
1810code is not reachable. This can be used to indicate that the code after a
1811no-return function cannot be reached, and other facts.</p>
1812
1813<h5>Semantics:</h5>
1814
1815<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
1816</div>
1817
1818
1819
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1820<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1821<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1822<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1823<p>Binary operators are used to do most of the computation in a
1824program. They require two operands, execute an operation on them, and
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1825produce a single value. The operands might represent
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1826multiple data, as is the case with the <a href="#t_vector">vector</a> data type.
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1827The result value of a binary operator is not
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1828necessarily the same type as its operands.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1829<p>There are several different binary operators:</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1830</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1831<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1832<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
1833Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1834<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1835<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1836<pre> &lt;result&gt; = add &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1837</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1838<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1839<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1840<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1841<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1842 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1843 This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1844Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1845<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1846<p>The value produced is the integer or floating point sum of the two
1847operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1848<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1849<pre> &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1850</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1851</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1852<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1853<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
1854Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1855<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1856<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1857<pre> &lt;result&gt; = sub &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1858</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1859<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1860<p>The '<tt>sub</tt>' instruction returns the difference of its two
1861operands.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1862<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
1863instruction present in most other intermediate representations.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1864<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1865<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1866 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1867values.
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1868This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1869Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1870<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1871<p>The value produced is the integer or floating point difference of
1872the two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1873<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1874<pre> &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
1875 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1876</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1877</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1878<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1879<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
1880Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1881<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1882<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1883<pre> &lt;result&gt; = mul &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1884</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1885<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1886<p>The '<tt>mul</tt>' instruction returns the product of its two
1887operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1888<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1889<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1890 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1891values.
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1892This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1893Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1894<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1895<p>The value produced is the integer or floating point product of the
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1896two operands.</p>
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1897<p>Because the operands are the same width, the result of an integer
1898multiplication is the same whether the operands should be deemed unsigned or
1899signed.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1900<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1901<pre> &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1902</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1903</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1904<!-- _______________________________________________________________________ -->
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]1905<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
1906</a></div>
1907<div class="doc_text">
1908<h5>Syntax:</h5>
1909<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1910</pre>
1911<h5>Overview:</h5>
1912<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
1913operands.</p>
1914<h5>Arguments:</h5>
1915<p>The two arguments to the '<tt>udiv</tt>' instruction must be
1916<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1917types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]1918of the values in which case the elements must be integers.</p>
1919<h5>Semantics:</h5>
1920<p>The value produced is the unsigned integer quotient of the two operands. This
1921instruction always performs an unsigned division operation, regardless of
1922whether the arguments are unsigned or not.</p>
1923<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1924<pre> &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]1925</pre>
1926</div>
1927<!-- _______________________________________________________________________ -->
1928<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
1929</a> </div>
1930<div class="doc_text">
1931<h5>Syntax:</h5>
1932<pre> &lt;result&gt; = sdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1933</pre>
1934<h5>Overview:</h5>
1935<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
1936operands.</p>
1937<h5>Arguments:</h5>
1938<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
1939<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1940types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]1941of the values in which case the elements must be integers.</p>
1942<h5>Semantics:</h5>
1943<p>The value produced is the signed integer quotient of the two operands. This
1944instruction always performs a signed division operation, regardless of whether
1945the arguments are signed or not.</p>
1946<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1947<pre> &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]1948</pre>
1949</div>
1950<!-- _______________________________________________________________________ -->
1951<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1952Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1953<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1954<h5>Syntax:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]1955<pre> &lt;result&gt; = fdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1956</pre>
1957<h5>Overview:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]1958<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1959operands.</p>
1960<h5>Arguments:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]1961<p>The two arguments to the '<tt>div</tt>' instruction must be
1962<a href="#t_floating">floating point</a> values. Both arguments must have
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1963identical types. This instruction can also take <a href="#t_vector">vector</a>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]1964versions of the values in which case the elements must be floating point.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1965<h5>Semantics:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]1966<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1967<h5>Example:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]1968<pre> &lt;result&gt; = fdiv float 4.0, %var <i>; yields {float}:result = 4.0 / %var</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1969</pre>
1970</div>
1971<!-- _______________________________________________________________________ -->
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]1972<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
1973</div>
1974<div class="doc_text">
1975<h5>Syntax:</h5>
1976<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1977</pre>
1978<h5>Overview:</h5>
1979<p>The '<tt>urem</tt>' instruction returns the remainder from the
1980unsigned division of its two arguments.</p>
1981<h5>Arguments:</h5>
1982<p>The two arguments to the '<tt>urem</tt>' instruction must be
1983<a href="#t_integer">integer</a> values. Both arguments must have identical
1984types.</p>
1985<h5>Semantics:</h5>
1986<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
1987This instruction always performs an unsigned division to get the remainder,
1988regardless of whether the arguments are unsigned or not.</p>
1989<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1990<pre> &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]1991</pre>
1992
1993</div>
1994<!-- _______________________________________________________________________ -->
1995<div class="doc_subsubsection"> <a name="i_srem">'<tt>srem</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1996Instruction</a> </div>
1997<div class="doc_text">
1998<h5>Syntax:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]1999<pre> &lt;result&gt; = srem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2000</pre>
2001<h5>Overview:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2002<p>The '<tt>srem</tt>' instruction returns the remainder from the
2003signed division of its two operands.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2004<h5>Arguments:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2005<p>The two arguments to the '<tt>srem</tt>' instruction must be
2006<a href="#t_integer">integer</a> values. Both arguments must have identical
2007types.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2008<h5>Semantics:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2009<p>This instruction returns the <i>remainder</i> of a division (where the result
Reid Spencer806ad6a2007-03-24 22:23:39 +0000[diff] [blame]2010has the same sign as the dividend, <tt>var1</tt>), not the <i>modulo</i>
2011operator (where the result has the same sign as the divisor, <tt>var2</tt>) of
2012a value. For more information about the difference, see <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2013 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
Reid Spencer806ad6a2007-03-24 22:23:39 +0000[diff] [blame]2014Math Forum</a>. For a table of how this is implemented in various languages,
Reid Spencerdb3b93b2007-03-24 22:40:44 +0000[diff] [blame]2015please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
Reid Spencer806ad6a2007-03-24 22:23:39 +0000[diff] [blame]2016Wikipedia: modulo operation</a>.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2017<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2018<pre> &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2019</pre>
2020
2021</div>
2022<!-- _______________________________________________________________________ -->
2023<div class="doc_subsubsection"> <a name="i_frem">'<tt>frem</tt>'
2024Instruction</a> </div>
2025<div class="doc_text">
2026<h5>Syntax:</h5>
2027<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2028</pre>
2029<h5>Overview:</h5>
2030<p>The '<tt>frem</tt>' instruction returns the remainder from the
2031division of its two operands.</p>
2032<h5>Arguments:</h5>
2033<p>The two arguments to the '<tt>frem</tt>' instruction must be
2034<a href="#t_floating">floating point</a> values. Both arguments must have
2035identical types.</p>
2036<h5>Semantics:</h5>
2037<p>This instruction returns the <i>remainder</i> of a division.</p>
2038<h5>Example:</h5>
2039<pre> &lt;result&gt; = frem float 4.0, %var <i>; yields {float}:result = 4.0 % %var</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2040</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2041</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]2042
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]2043<!-- ======================================================================= -->
2044<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2045Operations</a> </div>
2046<div class="doc_text">
2047<p>Bitwise binary operators are used to do various forms of
2048bit-twiddling in a program. They are generally very efficient
2049instructions and can commonly be strength reduced from other
2050instructions. They require two operands, execute an operation on them,
2051and produce a single value. The resulting value of the bitwise binary
2052operators is always the same type as its first operand.</p>
2053</div>
2054
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2055<!-- _______________________________________________________________________ -->
2056<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2057Instruction</a> </div>
2058<div class="doc_text">
2059<h5>Syntax:</h5>
2060<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2061</pre>
2062<h5>Overview:</h5>
2063<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2064the left a specified number of bits.</p>
2065<h5>Arguments:</h5>
2066<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
2067 href="#t_integer">integer</a> type.</p>
2068<h5>Semantics:</h5>
2069<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>.</p>
2070<h5>Example:</h5><pre>
2071 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2072 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2073 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
2074</pre>
2075</div>
2076<!-- _______________________________________________________________________ -->
2077<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2078Instruction</a> </div>
2079<div class="doc_text">
2080<h5>Syntax:</h5>
2081<pre> &lt;result&gt; = lshr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2082</pre>
2083
2084<h5>Overview:</h5>
2085<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
2086operand shifted to the right a specified number of bits.</p>
2087
2088<h5>Arguments:</h5>
2089<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
2090<a href="#t_integer">integer</a> type.</p>
2091
2092<h5>Semantics:</h5>
2093<p>This instruction always performs a logical shift right operation. The most
2094significant bits of the result will be filled with zero bits after the
2095shift.</p>
2096
2097<h5>Example:</h5>
2098<pre>
2099 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2100 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2101 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2102 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
2103</pre>
2104</div>
2105
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]2106<!-- _______________________________________________________________________ -->
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2107<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2108Instruction</a> </div>
2109<div class="doc_text">
2110
2111<h5>Syntax:</h5>
2112<pre> &lt;result&gt; = ashr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2113</pre>
2114
2115<h5>Overview:</h5>
2116<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
2117operand shifted to the right a specified number of bits.</p>
2118
2119<h5>Arguments:</h5>
2120<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
2121<a href="#t_integer">integer</a> type.</p>
2122
2123<h5>Semantics:</h5>
2124<p>This instruction always performs an arithmetic shift right operation,
2125The most significant bits of the result will be filled with the sign bit
2126of <tt>var1</tt>.</p>
2127
2128<h5>Example:</h5>
2129<pre>
2130 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2131 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2132 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2133 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
2134</pre>
2135</div>
2136
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2137<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2138<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2139Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2140<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2141<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2142<pre> &lt;result&gt; = and &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2143</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2144<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2145<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2146its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2147<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2148<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]2149 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2150identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2151<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2152<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2153<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2154<div style="align: center">
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2155<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2156 <tbody>
2157 <tr>
2158 <td>In0</td>
2159 <td>In1</td>
2160 <td>Out</td>
2161 </tr>
2162 <tr>
2163 <td>0</td>
2164 <td>0</td>
2165 <td>0</td>
2166 </tr>
2167 <tr>
2168 <td>0</td>
2169 <td>1</td>
2170 <td>0</td>
2171 </tr>
2172 <tr>
2173 <td>1</td>
2174 <td>0</td>
2175 <td>0</td>
2176 </tr>
2177 <tr>
2178 <td>1</td>
2179 <td>1</td>
2180 <td>1</td>
2181 </tr>
2182 </tbody>
2183</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2184</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2185<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2186<pre> &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
2187 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2188 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2189</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2190</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2191<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2192<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2193<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2194<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2195<pre> &lt;result&gt; = or &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2196</pre>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2197<h5>Overview:</h5>
2198<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2199or of its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2200<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2201<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]2202 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2203identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2204<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2205<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2206<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2207<div style="align: center">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2208<table border="1" cellspacing="0" cellpadding="4">
2209 <tbody>
2210 <tr>
2211 <td>In0</td>
2212 <td>In1</td>
2213 <td>Out</td>
2214 </tr>
2215 <tr>
2216 <td>0</td>
2217 <td>0</td>
2218 <td>0</td>
2219 </tr>
2220 <tr>
2221 <td>0</td>
2222 <td>1</td>
2223 <td>1</td>
2224 </tr>
2225 <tr>
2226 <td>1</td>
2227 <td>0</td>
2228 <td>1</td>
2229 </tr>
2230 <tr>
2231 <td>1</td>
2232 <td>1</td>
2233 <td>1</td>
2234 </tr>
2235 </tbody>
2236</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2237</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2238<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2239<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2240 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2241 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2242</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2243</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2244<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2245<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2246Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2247<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2248<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2249<pre> &lt;result&gt; = xor &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2250</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2251<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2252<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2253or of its two operands. The <tt>xor</tt> is used to implement the
2254"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2255<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2256<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]2257 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2258identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2259<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2260<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2261<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2262<div style="align: center">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2263<table border="1" cellspacing="0" cellpadding="4">
2264 <tbody>
2265 <tr>
2266 <td>In0</td>
2267 <td>In1</td>
2268 <td>Out</td>
2269 </tr>
2270 <tr>
2271 <td>0</td>
2272 <td>0</td>
2273 <td>0</td>
2274 </tr>
2275 <tr>
2276 <td>0</td>
2277 <td>1</td>
2278 <td>1</td>
2279 </tr>
2280 <tr>
2281 <td>1</td>
2282 <td>0</td>
2283 <td>1</td>
2284 </tr>
2285 <tr>
2286 <td>1</td>
2287 <td>1</td>
2288 <td>0</td>
2289 </tr>
2290 </tbody>
2291</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2292</div>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2293<p> </p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2294<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2295<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2296 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2297 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2298 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2299</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2300</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2301
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2302<!-- ======================================================================= -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2303<div class="doc_subsection">
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2304 <a name="vectorops">Vector Operations</a>
2305</div>
2306
2307<div class="doc_text">
2308
2309<p>LLVM supports several instructions to represent vector operations in a
2310target-independent manner. This instructions cover the element-access and
2311vector-specific operations needed to process vectors effectively. While LLVM
2312does directly support these vector operations, many sophisticated algorithms
2313will want to use target-specific intrinsics to take full advantage of a specific
2314target.</p>
2315
2316</div>
2317
2318<!-- _______________________________________________________________________ -->
2319<div class="doc_subsubsection">
2320 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2321</div>
2322
2323<div class="doc_text">
2324
2325<h5>Syntax:</h5>
2326
2327<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2328 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2329</pre>
2330
2331<h5>Overview:</h5>
2332
2333<p>
2334The '<tt>extractelement</tt>' instruction extracts a single scalar
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2335element from a vector at a specified index.
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2336</p>
2337
2338
2339<h5>Arguments:</h5>
2340
2341<p>
2342The first operand of an '<tt>extractelement</tt>' instruction is a
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2343value of <a href="#t_vector">vector</a> type. The second operand is
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2344an index indicating the position from which to extract the element.
2345The index may be a variable.</p>
2346
2347<h5>Semantics:</h5>
2348
2349<p>
2350The result is a scalar of the same type as the element type of
2351<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2352<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2353results are undefined.
2354</p>
2355
2356<h5>Example:</h5>
2357
2358<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2359 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2360</pre>
2361</div>
2362
2363
2364<!-- _______________________________________________________________________ -->
2365<div class="doc_subsubsection">
2366 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2367</div>
2368
2369<div class="doc_text">
2370
2371<h5>Syntax:</h5>
2372
2373<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2374 &lt;result&gt; = insertelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, &lt;ty&gt; &lt;elt&gt, i32 &lt;idx&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2375</pre>
2376
2377<h5>Overview:</h5>
2378
2379<p>
2380The '<tt>insertelement</tt>' instruction inserts a scalar
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2381element into a vector at a specified index.
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2382</p>
2383
2384
2385<h5>Arguments:</h5>
2386
2387<p>
2388The first operand of an '<tt>insertelement</tt>' instruction is a
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2389value of <a href="#t_vector">vector</a> type. The second operand is a
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2390scalar value whose type must equal the element type of the first
2391operand. The third operand is an index indicating the position at
2392which to insert the value. The index may be a variable.</p>
2393
2394<h5>Semantics:</h5>
2395
2396<p>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2397The result is a vector of the same type as <tt>val</tt>. Its
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2398element values are those of <tt>val</tt> except at position
2399<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2400exceeds the length of <tt>val</tt>, the results are undefined.
2401</p>
2402
2403<h5>Example:</h5>
2404
2405<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2406 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2407</pre>
2408</div>
2409
2410<!-- _______________________________________________________________________ -->
2411<div class="doc_subsubsection">
2412 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2413</div>
2414
2415<div class="doc_text">
2416
2417<h5>Syntax:</h5>
2418
2419<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2420 &lt;result&gt; = shufflevector &lt;n x &lt;ty&gt;&gt; &lt;v1&gt;, &lt;n x &lt;ty&gt;&gt; &lt;v2&gt;, &lt;n x i32&gt; &lt;mask&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2421</pre>
2422
2423<h5>Overview:</h5>
2424
2425<p>
2426The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2427from two input vectors, returning a vector of the same type.
2428</p>
2429
2430<h5>Arguments:</h5>
2431
2432<p>
2433The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2434with types that match each other and types that match the result of the
2435instruction. The third argument is a shuffle mask, which has the same number
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2436of elements as the other vector type, but whose element type is always 'i32'.
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2437</p>
2438
2439<p>
2440The shuffle mask operand is required to be a constant vector with either
2441constant integer or undef values.
2442</p>
2443
2444<h5>Semantics:</h5>
2445
2446<p>
2447The elements of the two input vectors are numbered from left to right across
2448both of the vectors. The shuffle mask operand specifies, for each element of
2449the result vector, which element of the two input registers the result element
2450gets. The element selector may be undef (meaning "don't care") and the second
2451operand may be undef if performing a shuffle from only one vector.
2452</p>
2453
2454<h5>Example:</h5>
2455
2456<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2457 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
2458 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
2459 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2460 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i> - Identity shuffle.
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2461</pre>
2462</div>
2463
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]2464
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2465<!-- ======================================================================= -->
2466<div class="doc_subsection">
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]2467 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2468</div>
2469
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2470<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2471
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2472<p>A key design point of an SSA-based representation is how it
2473represents memory. In LLVM, no memory locations are in SSA form, which
2474makes things very simple. This section describes how to read, write,
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2475allocate, and free memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2476
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2477</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2478
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2479<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2480<div class="doc_subsubsection">
2481 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2482</div>
2483
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2484<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2485
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2486<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2487
2488<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2489 &lt;result&gt; = malloc &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2490</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2491
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2492<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2493
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2494<p>The '<tt>malloc</tt>' instruction allocates memory from the system
2495heap and returns a pointer to it.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2496
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2497<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2498
2499<p>The '<tt>malloc</tt>' instruction allocates
2500<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswella92e5862004-02-24 16:13:56 +0000[diff] [blame]2501bytes of memory from the operating system and returns a pointer of the
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2502appropriate type to the program. If "NumElements" is specified, it is the
2503number of elements allocated. If an alignment is specified, the value result
2504of the allocation is guaranteed to be aligned to at least that boundary. If
2505not specified, or if zero, the target can choose to align the allocation on any
2506convenient boundary.</p>
2507
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2508<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2509
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2510<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2511
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2512<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
2513a pointer is returned.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2514
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2515<h5>Example:</h5>
2516
2517<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2518 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2519
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2520 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
2521 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
2522 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
2523 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
2524 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2525</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2526</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2527
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2528<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2529<div class="doc_subsubsection">
2530 <a name="i_free">'<tt>free</tt>' Instruction</a>
2531</div>
2532
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2533<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2534
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2535<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2536
2537<pre>
2538 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2539</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2540
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2541<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2542
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2543<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]2544memory heap to be reallocated in the future.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2545
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2546<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2547
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2548<p>'<tt>value</tt>' shall be a pointer value that points to a value
2549that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
2550instruction.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2551
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2552<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2553
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2554<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2555after this instruction executes.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2556
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2557<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2558
2559<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2560 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
2561 free [4 x i8]* %array
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2562</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2563</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2564
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2565<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2566<div class="doc_subsubsection">
2567 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
2568</div>
2569
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2570<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2571
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2572<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2573
2574<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2575 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2576</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2577
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2578<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2579
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2580<p>The '<tt>alloca</tt>' instruction allocates memory on the current
2581stack frame of the procedure that is live until the current function
2582returns to its caller.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2583
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2584<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2585
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2586<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2587bytes of memory on the runtime stack, returning a pointer of the
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2588appropriate type to the program. If "NumElements" is specified, it is the
2589number of elements allocated. If an alignment is specified, the value result
2590of the allocation is guaranteed to be aligned to at least that boundary. If
2591not specified, or if zero, the target can choose to align the allocation on any
2592convenient boundary.</p>
2593
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2594<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2595
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2596<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2597
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]2598<p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2599memory is automatically released when the function returns. The '<tt>alloca</tt>'
2600instruction is commonly used to represent automatic variables that must
2601have an address available. When the function returns (either with the <tt><a
John Criswellc932bef2005-05-12 16:55:34 +0000[diff] [blame]2602 href="#i_ret">ret</a></tt> or <tt><a href="#i_unwind">unwind</a></tt>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2603instructions), the memory is reclaimed.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2604
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2605<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2606
2607<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2608 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
2609 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
2610 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
2611 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2612</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2613</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2614
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2615<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2616<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
2617Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2618<div class="doc_text">
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2619<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2620<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 Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2621<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2622<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2623<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2624<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]2625address from which to load. The pointer must point to a <a
Chris Lattner10ee9652004-06-03 22:57:15 +0000[diff] [blame]2626 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]2627marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2628the number or order of execution of this <tt>load</tt> with other
2629volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
2630instructions. </p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2631<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2632<p>The location of memory pointed to is loaded.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2633<h5>Examples:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2634<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2635 <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2636 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2637 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2638</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2639</div>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2640<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2641<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
2642Instruction</a> </div>
Reid Spencera89fb182006-11-09 21:18:01 +0000[diff] [blame]2643<div class="doc_text">
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2644<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2645<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt; <i>; yields {void}</i>
Chris Lattner12d456c2003-09-08 18:27:49 +0000[diff] [blame]2646 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt; <i>; yields {void}</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2647</pre>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2648<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2649<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2650<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2651<p>There are two arguments to the '<tt>store</tt>' instruction: a value
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]2652to store and an address in which to store it. The type of the '<tt>&lt;pointer&gt;</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2653operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]2654operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2655optimizer is not allowed to modify the number or order of execution of
2656this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
2657 href="#i_store">store</a></tt> instructions.</p>
2658<h5>Semantics:</h5>
2659<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
2660at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2661<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2662<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2663 <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2664 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2665 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2666</pre>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]2667</div>
2668
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2669<!-- _______________________________________________________________________ -->
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2670<div class="doc_subsubsection">
2671 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
2672</div>
2673
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2674<div class="doc_text">
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2675<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2676<pre>
2677 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
2678</pre>
2679
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2680<h5>Overview:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2681
2682<p>
2683The '<tt>getelementptr</tt>' instruction is used to get the address of a
2684subelement of an aggregate data structure.</p>
2685
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2686<h5>Arguments:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2687
Reid Spencercee005c2006-12-04 21:29:24 +0000[diff] [blame]2688<p>This instruction takes a list of integer operands that indicate what
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2689elements of the aggregate object to index to. The actual types of the arguments
2690provided depend on the type of the first pointer argument. The
2691'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]2692levels of a structure or to a specific index in an array. When indexing into a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2693structure, only <tt>i32</tt> integer constants are allowed. When indexing
Reid Spencercee005c2006-12-04 21:29:24 +0000[diff] [blame]2694into an array or pointer, only integers of 32 or 64 bits are allowed, and will
2695be sign extended to 64-bit values.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2696
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2697<p>For example, let's consider a C code fragment and how it gets
2698compiled to LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2699
2700<pre>
2701 struct RT {
2702 char A;
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2703 i32 B[10][20];
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2704 char C;
2705 };
2706 struct ST {
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2707 i32 X;
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2708 double Y;
2709 struct RT Z;
2710 };
2711
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2712 define i32 *foo(struct ST *s) {
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2713 return &amp;s[1].Z.B[5][13];
2714 }
2715</pre>
2716
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2717<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2718
2719<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2720 %RT = type { i8 , [10 x [20 x i32]], i8 }
2721 %ST = type { i32, double, %RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2722
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2723 define i32* %foo(%ST* %s) {
Brian Gaeke317ef962004-07-02 21:08:14 +0000[diff] [blame]2724 entry:
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2725 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
2726 ret i32* %reg
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2727 }
2728</pre>
2729
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2730<h5>Semantics:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2731
2732<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]2733on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Reid Spencercee005c2006-12-04 21:29:24 +0000[diff] [blame]2734and <a href="#t_array">array</a> types can use a 32-bit or 64-bit
Reid Spencerc0312692006-12-03 16:53:48 +0000[diff] [blame]2735<a href="#t_integer">integer</a> type but the value will always be sign extended
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2736to 64-bits. <a href="#t_struct">Structure</a> types, require <tt>i32</tt>
Reid Spencerc0312692006-12-03 16:53:48 +0000[diff] [blame]2737<b>constants</b>.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2738
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2739<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2740type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2741}</tt>' type, a structure. The second index indexes into the third element of
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2742the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
2743i8 }</tt>' type, another structure. The third index indexes into the second
2744element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2745array. The two dimensions of the array are subscripted into, yielding an
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2746'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
2747to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2748
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2749<p>Note that it is perfectly legal to index partially through a
2750structure, returning a pointer to an inner element. Because of this,
2751the LLVM code for the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2752
2753<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2754 define i32* %foo(%ST* %s) {
2755 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
2756 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
2757 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
2758 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
2759 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
2760 ret i32* %t5
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2761 }
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2762</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]2763
2764<p>Note that it is undefined to access an array out of bounds: array and
2765pointer indexes must always be within the defined bounds of the array type.
2766The one exception for this rules is zero length arrays. These arrays are
2767defined to be accessible as variable length arrays, which requires access
2768beyond the zero'th element.</p>
2769
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]2770<p>The getelementptr instruction is often confusing. For some more insight
2771into how it works, see <a href="GetElementPtr.html">the getelementptr
2772FAQ</a>.</p>
2773
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2774<h5>Example:</h5>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]2775
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2776<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2777 <i>; yields [12 x i8]*:aptr</i>
2778 %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2779</pre>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2780</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]2781
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2782<!-- ======================================================================= -->
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]2783<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2784</div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2785<div class="doc_text">
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]2786<p>The instructions in this category are the conversion instructions (casting)
2787which all take a single operand and a type. They perform various bit conversions
2788on the operand.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2789</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2790
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2791<!-- _______________________________________________________________________ -->
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2792<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2793 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
2794</div>
2795<div class="doc_text">
2796
2797<h5>Syntax:</h5>
2798<pre>
2799 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2800</pre>
2801
2802<h5>Overview:</h5>
2803<p>
2804The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
2805</p>
2806
2807<h5>Arguments:</h5>
2808<p>
2809The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
2810be an <a href="#t_integer">integer</a> type, and a type that specifies the size
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]2811and type of the result, which must be an <a href="#t_integer">integer</a>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2812type. The bit size of <tt>value</tt> must be larger than the bit size of
2813<tt>ty2</tt>. Equal sized types are not allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2814
2815<h5>Semantics:</h5>
2816<p>
2817The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2818and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
2819larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
2820It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2821
2822<h5>Example:</h5>
2823<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2824 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2825 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
2826 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2827</pre>
2828</div>
2829
2830<!-- _______________________________________________________________________ -->
2831<div class="doc_subsubsection">
2832 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
2833</div>
2834<div class="doc_text">
2835
2836<h5>Syntax:</h5>
2837<pre>
2838 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2839</pre>
2840
2841<h5>Overview:</h5>
2842<p>The '<tt>zext</tt>' instruction zero extends its operand to type
2843<tt>ty2</tt>.</p>
2844
2845
2846<h5>Arguments:</h5>
2847<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]2848<a href="#t_integer">integer</a> type, and a type to cast it to, which must
2849also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2850<tt>value</tt> must be smaller than the bit size of the destination type,
2851<tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2852
2853<h5>Semantics:</h5>
2854<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
2855bits until it reaches the size of the destination type, <tt>ty2</tt>. When the
2856the operand and the type are the same size, no bit filling is done and the
2857cast is considered a <i>no-op cast</i> because no bits change (only the type
2858changes).</p>
2859
Reid Spencer07c9c682007-01-12 15:46:11 +0000[diff] [blame]2860<p>When zero extending from i1, the result will always be either 0 or 1.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2861
2862<h5>Example:</h5>
2863<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2864 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2865 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2866</pre>
2867</div>
2868
2869<!-- _______________________________________________________________________ -->
2870<div class="doc_subsubsection">
2871 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
2872</div>
2873<div class="doc_text">
2874
2875<h5>Syntax:</h5>
2876<pre>
2877 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2878</pre>
2879
2880<h5>Overview:</h5>
2881<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
2882
2883<h5>Arguments:</h5>
2884<p>
2885The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]2886<a href="#t_integer">integer</a> type, and a type to cast it to, which must
2887also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2888<tt>value</tt> must be smaller than the bit size of the destination type,
2889<tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2890
2891<h5>Semantics:</h5>
2892<p>
2893The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
2894bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
2895the type <tt>ty2</tt>. When the the operand and the type are the same size,
2896no bit filling is done and the cast is considered a <i>no-op cast</i> because
2897no bits change (only the type changes).</p>
2898
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2899<p>When sign extending from i1, the extension always results in -1 or 0.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2900
2901<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2902<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2903 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2904 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2905</pre>
2906</div>
2907
2908<!-- _______________________________________________________________________ -->
2909<div class="doc_subsubsection">
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]2910 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
2911</div>
2912
2913<div class="doc_text">
2914
2915<h5>Syntax:</h5>
2916
2917<pre>
2918 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2919</pre>
2920
2921<h5>Overview:</h5>
2922<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
2923<tt>ty2</tt>.</p>
2924
2925
2926<h5>Arguments:</h5>
2927<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
2928 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
2929cast it to. The size of <tt>value</tt> must be larger than the size of
2930<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
2931<i>no-op cast</i>.</p>
2932
2933<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2934<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
2935<a href="#t_floating">floating point</a> type to a smaller
2936<a href="#t_floating">floating point</a> type. If the value cannot fit within
2937the destination type, <tt>ty2</tt>, then the results are undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]2938
2939<h5>Example:</h5>
2940<pre>
2941 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
2942 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
2943</pre>
2944</div>
2945
2946<!-- _______________________________________________________________________ -->
2947<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2948 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
2949</div>
2950<div class="doc_text">
2951
2952<h5>Syntax:</h5>
2953<pre>
2954 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2955</pre>
2956
2957<h5>Overview:</h5>
2958<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
2959floating point value.</p>
2960
2961<h5>Arguments:</h5>
2962<p>The '<tt>fpext</tt>' instruction takes a
2963<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2964and a <a href="#t_floating">floating point</a> type to cast it to. The source
2965type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2966
2967<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2968<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
2969<a href="t_floating">floating point</a> type to a larger
2970<a href="t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
2971used to make a <i>no-op cast</i> because it always changes bits. Use
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2972<tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2973
2974<h5>Example:</h5>
2975<pre>
2976 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
2977 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
2978</pre>
2979</div>
2980
2981<!-- _______________________________________________________________________ -->
2982<div class="doc_subsubsection">
Reid Spencer2eadb532007-01-21 00:29:26 +0000[diff] [blame]2983 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2984</div>
2985<div class="doc_text">
2986
2987<h5>Syntax:</h5>
2988<pre>
2989 &lt;result&gt; = fp2uint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2990</pre>
2991
2992<h5>Overview:</h5>
2993<p>The '<tt>fp2uint</tt>' converts a floating point <tt>value</tt> to its
2994unsigned integer equivalent of type <tt>ty2</tt>.
2995</p>
2996
2997<h5>Arguments:</h5>
2998<p>The '<tt>fp2uint</tt>' instruction takes a value to cast, which must be a
2999<a href="#t_floating">floating point</a> value, and a type to cast it to, which
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]3000must be an <a href="#t_integer">integer</a> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3001
3002<h5>Semantics:</h5>
3003<p> The '<tt>fp2uint</tt>' instruction converts its
3004<a href="#t_floating">floating point</a> operand into the nearest (rounding
3005towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3006the results are undefined.</p>
3007
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3008<p>When converting to i1, the conversion is done as a comparison against
3009zero. If the <tt>value</tt> was zero, the i1 result will be <tt>false</tt>.
3010If the <tt>value</tt> was non-zero, the i1 result will be <tt>true</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3011
3012<h5>Example:</h5>
3013<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3014 %X = fp2uint double 123.0 to i32 <i>; yields i32:123</i>
3015 %Y = fp2uint float 1.0E+300 to i1 <i>; yields i1:true</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3016 %X = fp2uint float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3017</pre>
3018</div>
3019
3020<!-- _______________________________________________________________________ -->
3021<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3022 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3023</div>
3024<div class="doc_text">
3025
3026<h5>Syntax:</h5>
3027<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3028 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3029</pre>
3030
3031<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3032<p>The '<tt>fptosi</tt>' instruction converts
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3033<a href="#t_floating">floating point</a> <tt>value</tt> to type <tt>ty2</tt>.
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3034</p>
3035
3036
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3037<h5>Arguments:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3038<p> The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3039<a href="#t_floating">floating point</a> value, and a type to cast it to, which
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]3040must also be an <a href="#t_integer">integer</a> type.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3041
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3042<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3043<p>The '<tt>fptosi</tt>' instruction converts its
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3044<a href="#t_floating">floating point</a> operand into the nearest (rounding
3045towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3046the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3047
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3048<p>When converting to i1, the conversion is done as a comparison against
3049zero. If the <tt>value</tt> was zero, the i1 result will be <tt>false</tt>.
3050If the <tt>value</tt> was non-zero, the i1 result will be <tt>true</tt>.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3051
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]3052<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3053<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3054 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
3055 %Y = fptosi float 1.0E-247 to i1 <i>; yields i1:true</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3056 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3057</pre>
3058</div>
3059
3060<!-- _______________________________________________________________________ -->
3061<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3062 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3063</div>
3064<div class="doc_text">
3065
3066<h5>Syntax:</h5>
3067<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3068 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3069</pre>
3070
3071<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3072<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3073integer and converts that value to the <tt>ty2</tt> type.</p>
3074
3075
3076<h5>Arguments:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3077<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be an
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]3078<a href="#t_integer">integer</a> value, and a type to cast it to, which must
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3079be a <a href="#t_floating">floating point</a> type.</p>
3080
3081<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3082<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3083integer quantity and converts it to the corresponding floating point value. If
3084the value cannot fit in the floating point value, the results are undefined.</p>
3085
3086
3087<h5>Example:</h5>
3088<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3089 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
3090 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3091</pre>
3092</div>
3093
3094<!-- _______________________________________________________________________ -->
3095<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3096 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3097</div>
3098<div class="doc_text">
3099
3100<h5>Syntax:</h5>
3101<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3102 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3103</pre>
3104
3105<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3106<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3107integer and converts that value to the <tt>ty2</tt> type.</p>
3108
3109<h5>Arguments:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3110<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be an
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]3111<a href="#t_integer">integer</a> value, and a type to cast it to, which must be
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3112a <a href="#t_floating">floating point</a> type.</p>
3113
3114<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3115<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3116integer quantity and converts it to the corresponding floating point value. If
3117the value cannot fit in the floating point value, the results are undefined.</p>
3118
3119<h5>Example:</h5>
3120<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3121 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
3122 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3123</pre>
3124</div>
3125
3126<!-- _______________________________________________________________________ -->
3127<div class="doc_subsubsection">
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3128 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3129</div>
3130<div class="doc_text">
3131
3132<h5>Syntax:</h5>
3133<pre>
3134 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3135</pre>
3136
3137<h5>Overview:</h5>
3138<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3139the integer type <tt>ty2</tt>.</p>
3140
3141<h5>Arguments:</h5>
3142<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
3143must be a <a href="t_pointer">pointer</a> value, and a type to cast it to
3144<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
3145
3146<h5>Semantics:</h5>
3147<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3148<tt>ty2</tt> by interpreting the pointer value as an integer and either
3149truncating or zero extending that value to the size of the integer type. If
3150<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3151<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
3152are the same size, then nothing is done (<i>no-op cast</i>).</p>
3153
3154<h5>Example:</h5>
3155<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3156 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit</i>
3157 %Y = ptrtoint i32* %x to i64 <i>; yields zero extend on 32-bit</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3158</pre>
3159</div>
3160
3161<!-- _______________________________________________________________________ -->
3162<div class="doc_subsubsection">
3163 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3164</div>
3165<div class="doc_text">
3166
3167<h5>Syntax:</h5>
3168<pre>
3169 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3170</pre>
3171
3172<h5>Overview:</h5>
3173<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3174a pointer type, <tt>ty2</tt>.</p>
3175
3176<h5>Arguments:</h5>
3177<p>The '<tt>inttoptr</tt>' instruction takes an <a href="i_integer">integer</a>
3178value to cast, and a type to cast it to, which must be a
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]3179<a href="#t_pointer">pointer</a> type.
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3180
3181<h5>Semantics:</h5>
3182<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3183<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3184the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3185size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3186the size of a pointer then a zero extension is done. If they are the same size,
3187nothing is done (<i>no-op cast</i>).</p>
3188
3189<h5>Example:</h5>
3190<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3191 %X = inttoptr i32 255 to i32* <i>; yields zero extend on 64-bit</i>
3192 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit </i>
3193 %Y = inttoptr i16 0 to i32* <i>; yields zero extend on 32-bit</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3194</pre>
3195</div>
3196
3197<!-- _______________________________________________________________________ -->
3198<div class="doc_subsubsection">
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3199 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3200</div>
3201<div class="doc_text">
3202
3203<h5>Syntax:</h5>
3204<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3205 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3206</pre>
3207
3208<h5>Overview:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3209<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3210<tt>ty2</tt> without changing any bits.</p>
3211
3212<h5>Arguments:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3213<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3214a first class value, and a type to cast it to, which must also be a <a
3215 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
Reid Spencere3db84c2007-01-09 20:08:58 +0000[diff] [blame]3216and the destination type, <tt>ty2</tt>, must be identical. If the source
3217type is a pointer, the destination type must also be a pointer.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3218
3219<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3220<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3221<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3222this conversion. The conversion is done as if the <tt>value</tt> had been
3223stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3224converted to other pointer types with this instruction. To convert pointers to
3225other types, use the <a href="#i_inttoptr">inttoptr</a> or
3226<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3227
3228<h5>Example:</h5>
3229<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3230 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
3231 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
3232 %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]3233</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3234</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3235
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3236<!-- ======================================================================= -->
3237<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3238<div class="doc_text">
3239<p>The instructions in this category are the "miscellaneous"
3240instructions, which defy better classification.</p>
3241</div>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3242
3243<!-- _______________________________________________________________________ -->
3244<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3245</div>
3246<div class="doc_text">
3247<h5>Syntax:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3248<pre> &lt;result&gt; = icmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt;
3249<i>; yields {i1}:result</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3250</pre>
3251<h5>Overview:</h5>
3252<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
3253of its two integer operands.</p>
3254<h5>Arguments:</h5>
3255<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
3256the condition code which indicates the kind of comparison to perform. It is not
3257a value, just a keyword. The possibilities for the condition code are:
3258<ol>
3259 <li><tt>eq</tt>: equal</li>
3260 <li><tt>ne</tt>: not equal </li>
3261 <li><tt>ugt</tt>: unsigned greater than</li>
3262 <li><tt>uge</tt>: unsigned greater or equal</li>
3263 <li><tt>ult</tt>: unsigned less than</li>
3264 <li><tt>ule</tt>: unsigned less or equal</li>
3265 <li><tt>sgt</tt>: signed greater than</li>
3266 <li><tt>sge</tt>: signed greater or equal</li>
3267 <li><tt>slt</tt>: signed less than</li>
3268 <li><tt>sle</tt>: signed less or equal</li>
3269</ol>
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]3270<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Reid Spencer784ef792007-01-04 05:19:58 +0000[diff] [blame]3271<a href="#t_pointer">pointer</a> typed. They must also be identical types.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3272<h5>Semantics:</h5>
3273<p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3274the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3275yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3276<ol>
3277 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3278 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3279 </li>
3280 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3281 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3282 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3283 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3284 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3285 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3286 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3287 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3288 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3289 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3290 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3291 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3292 <li><tt>sge</tt>: interprets the operands as signed values and yields
3293 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3294 <li><tt>slt</tt>: interprets the operands as signed values and yields
3295 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3296 <li><tt>sle</tt>: interprets the operands as signed values and yields
3297 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3298</ol>
3299<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
3300values are treated as integers and then compared.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3301
3302<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3303<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3304 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3305 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3306 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3307 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3308 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3309</pre>
3310</div>
3311
3312<!-- _______________________________________________________________________ -->
3313<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3314</div>
3315<div class="doc_text">
3316<h5>Syntax:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3317<pre> &lt;result&gt; = fcmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt;
3318<i>; yields {i1}:result</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3319</pre>
3320<h5>Overview:</h5>
3321<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3322of its floating point operands.</p>
3323<h5>Arguments:</h5>
3324<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
3325the condition code which indicates the kind of comparison to perform. It is not
3326a value, just a keyword. The possibilities for the condition code are:
3327<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3328 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3329 <li><tt>oeq</tt>: ordered and equal</li>
3330 <li><tt>ogt</tt>: ordered and greater than </li>
3331 <li><tt>oge</tt>: ordered and greater than or equal</li>
3332 <li><tt>olt</tt>: ordered and less than </li>
3333 <li><tt>ole</tt>: ordered and less than or equal</li>
3334 <li><tt>one</tt>: ordered and not equal</li>
3335 <li><tt>ord</tt>: ordered (no nans)</li>
3336 <li><tt>ueq</tt>: unordered or equal</li>
3337 <li><tt>ugt</tt>: unordered or greater than </li>
3338 <li><tt>uge</tt>: unordered or greater than or equal</li>
3339 <li><tt>ult</tt>: unordered or less than </li>
3340 <li><tt>ule</tt>: unordered or less than or equal</li>
3341 <li><tt>une</tt>: unordered or not equal</li>
3342 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3343 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3344</ol>
Reid Spencer02e0d1d2006-12-06 07:08:07 +0000[diff] [blame]3345<p>In the preceding, <i>ordered</i> means that neither operand is a QNAN while
3346<i>unordered</i> means that either operand may be a QNAN.</p>
Reid Spencer784ef792007-01-04 05:19:58 +0000[diff] [blame]3347<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be
3348<a href="#t_floating">floating point</a> typed. They must have identical
3349types.</p>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3350<p>In the foregoing, <i>ordered</i> means that neither operand is a QNAN and
3351<i>unordered</i> means that either operand is a QNAN.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3352<h5>Semantics:</h5>
3353<p>The '<tt>fcmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3354the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3355yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3356<ol>
3357 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3358 <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3359 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3360 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3361 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3362 <li><tt>oge</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3363 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3364 <li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3365 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3366 <li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3367 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3368 <li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3369 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3370 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3371 <li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3372 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3373 <li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3374 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3375 <li><tt>uge</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3376 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3377 <li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3378 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3379 <li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3380 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3381 <li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3382 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3383 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3384 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3385</ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3386
3387<h5>Example:</h5>
3388<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3389 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3390 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3391 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3392</pre>
3393</div>
3394
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3395<!-- _______________________________________________________________________ -->
3396<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
3397Instruction</a> </div>
3398<div class="doc_text">
3399<h5>Syntax:</h5>
3400<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
3401<h5>Overview:</h5>
3402<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
3403the SSA graph representing the function.</p>
3404<h5>Arguments:</h5>
3405<p>The type of the incoming values are specified with the first type
3406field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
3407as arguments, with one pair for each predecessor basic block of the
3408current block. Only values of <a href="#t_firstclass">first class</a>
3409type may be used as the value arguments to the PHI node. Only labels
3410may be used as the label arguments.</p>
3411<p>There must be no non-phi instructions between the start of a basic
3412block and the PHI instructions: i.e. PHI instructions must be first in
3413a basic block.</p>
3414<h5>Semantics:</h5>
3415<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the
3416value specified by the parameter, depending on which basic block we
3417came from in the last <a href="#terminators">terminator</a> instruction.</p>
3418<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3419<pre>Loop: ; Infinite loop that counts from 0 on up...<br> %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]<br> %nextindvar = add i32 %indvar, 1<br> br label %Loop<br></pre>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3420</div>
3421
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3422<!-- _______________________________________________________________________ -->
3423<div class="doc_subsubsection">
3424 <a name="i_select">'<tt>select</tt>' Instruction</a>
3425</div>
3426
3427<div class="doc_text">
3428
3429<h5>Syntax:</h5>
3430
3431<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3432 &lt;result&gt; = select i1 &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3433</pre>
3434
3435<h5>Overview:</h5>
3436
3437<p>
3438The '<tt>select</tt>' instruction is used to choose one value based on a
3439condition, without branching.
3440</p>
3441
3442
3443<h5>Arguments:</h5>
3444
3445<p>
3446The '<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.
3447</p>
3448
3449<h5>Semantics:</h5>
3450
3451<p>
3452If the boolean condition evaluates to true, the instruction returns the first
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3453value argument; otherwise, it returns the second value argument.
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3454</p>
3455
3456<h5>Example:</h5>
3457
3458<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3459 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3460</pre>
3461</div>
3462
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]3463
3464<!-- _______________________________________________________________________ -->
3465<div class="doc_subsubsection">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3466 <a name="i_call">'<tt>call</tt>' Instruction</a>
3467</div>
3468
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3469<div class="doc_text">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3470
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3471<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3472<pre>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3473 &lt;result&gt; = [tail] call [<a href="#callingconv">cconv</a>] &lt;ty&gt;* &lt;fnptrval&gt;(&lt;param list&gt;)
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3474</pre>
3475
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3476<h5>Overview:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3477
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3478<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3479
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3480<h5>Arguments:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3481
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3482<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3483
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3484<ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3485 <li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3486 <p>The optional "tail" marker indicates whether the callee function accesses
3487 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3488 function call is eligible for tail call optimization. Note that calls may
3489 be marked "tail" even if they do not occur before a <a
3490 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3491 </li>
3492 <li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3493 <p>The optional "cconv" marker indicates which <a href="callingconv">calling
3494 convention</a> the call should use. If none is specified, the call defaults
3495 to using C calling conventions.
3496 </li>
3497 <li>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3498 <p>'<tt>ty</tt>': shall be the signature of the pointer to function value
3499 being invoked. The argument types must match the types implied by this
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3500 signature. This type can be omitted if the function is not varargs and
3501 if the function type does not return a pointer to a function.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3502 </li>
3503 <li>
3504 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
3505 be invoked. In most cases, this is a direct function invocation, but
3506 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3507 to function value.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3508 </li>
3509 <li>
3510 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencerd845d162005-05-01 22:22:57 +0000[diff] [blame]3511 function signature argument types. All arguments must be of
3512 <a href="#t_firstclass">first class</a> type. If the function signature
3513 indicates the function accepts a variable number of arguments, the extra
3514 arguments can be specified.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3515 </li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3516</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3517
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3518<h5>Semantics:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3519
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3520<p>The '<tt>call</tt>' instruction is used to cause control flow to
3521transfer to a specified function, with its incoming arguments bound to
3522the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
3523instruction in the called function, control flow continues with the
3524instruction after the function call, and the return value of the
3525function is bound to the result argument. This is a simpler case of
3526the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3527
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3528<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3529
3530<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3531 %retval = call i32 %test(i32 %argc)
3532 call i32(i8 *, ...) *%printf(i8 * %msg, i32 12, i8 42);
3533 %X = tail call i32 %foo()
3534 %Y = tail call <a href="#callingconv">fastcc</a> i32 %foo()
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3535</pre>
3536
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3537</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3538
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3539<!-- _______________________________________________________________________ -->
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3540<div class="doc_subsubsection">
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]3541 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3542</div>
3543
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3544<div class="doc_text">
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3545
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3546<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3547
3548<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3549 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3550</pre>
3551
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3552<h5>Overview:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3553
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3554<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3555the "variable argument" area of a function call. It is used to implement the
3556<tt>va_arg</tt> macro in C.</p>
3557
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3558<h5>Arguments:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3559
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3560<p>This instruction takes a <tt>va_list*</tt> value and the type of
3561the argument. It returns a value of the specified argument type and
Jeff Cohendc6bfea2005-11-11 02:15:27 +0000[diff] [blame]3562increments the <tt>va_list</tt> to point to the next argument. Again, the
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3563actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3564
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3565<h5>Semantics:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3566
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3567<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
3568type from the specified <tt>va_list</tt> and causes the
3569<tt>va_list</tt> to point to the next argument. For more information,
3570see the variable argument handling <a href="#int_varargs">Intrinsic
3571Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3572
3573<p>It is legal for this instruction to be called in a function which does not
3574take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3575function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3576
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3577<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3578href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3579argument.</p>
3580
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3581<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3582
3583<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
3584
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3585</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3586
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3587<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3588<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
3589<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3590
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3591<div class="doc_text">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3592
3593<p>LLVM supports the notion of an "intrinsic function". These functions have
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3594well known names and semantics and are required to follow certain
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3595restrictions. Overall, these instructions represent an extension mechanism for
3596the LLVM language that does not require changing all of the transformations in
3597LLVM to add to the language (or the bytecode reader/writer, the parser,
3598etc...).</p>
3599
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3600<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
3601prefix is reserved in LLVM for intrinsic names; thus, functions may not be named
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3602this. Intrinsic functions must always be external functions: you cannot define
3603the body of intrinsic functions. Intrinsic functions may only be used in call
3604or invoke instructions: it is illegal to take the address of an intrinsic
3605function. Additionally, because intrinsic functions are part of the LLVM
3606language, it is required that they all be documented here if any are added.</p>
3607
3608
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3609<p>To learn how to add an intrinsic function, please see the <a
Chris Lattner90391c12005-05-11 03:35:57 +0000[diff] [blame]3610href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3611</p>
3612
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3613</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3614
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3615<!-- ======================================================================= -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3616<div class="doc_subsection">
3617 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
3618</div>
3619
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3620<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3621
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3622<p>Variable argument support is defined in LLVM with the <a
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]3623 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3624intrinsic functions. These functions are related to the similarly
3625named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3626
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3627<p>All of these functions operate on arguments that use a
3628target-specific value type "<tt>va_list</tt>". The LLVM assembly
3629language reference manual does not define what this type is, so all
3630transformations should be prepared to handle intrinsics with any type
3631used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3632
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]3633<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3634instruction and the variable argument handling intrinsic functions are
3635used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3636
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3637<pre>
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]3638define i32 @test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3639 ; Initialize variable argument processing
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3640 %ap = alloca i8 *
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3641 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]3642 call void @llvm.va_start(i8* %ap2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3643
3644 ; Read a single integer argument
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3645 %tmp = va_arg i8 ** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3646
3647 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3648 %aq = alloca i8 *
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3649 %aq2 = bitcast i8** %aq to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]3650 call void @llvm.va_copy(i8 *%aq2, i8* %ap2)
3651 call void @llvm.va_end(i8* %aq2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3652
3653 ; Stop processing of arguments.
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]3654 call void @llvm.va_end(i8* %ap2)
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3655 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3656}
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]3657
3658declare void @llvm.va_start(i8*)
3659declare void @llvm.va_copy(i8*, i8*)
3660declare void @llvm.va_end(i8*)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3661</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3662</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3663
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3664<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3665<div class="doc_subsubsection">
3666 <a name="i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
3667</div>
3668
3669
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3670<div class="doc_text">
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3671<h5>Syntax:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3672<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3673<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3674<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
3675<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
3676href="#i_va_arg">va_arg</a></tt>.</p>
3677
3678<h5>Arguments:</h5>
3679
3680<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
3681
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3682<h5>Semantics:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3683
3684<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
3685macro available in C. In a target-dependent way, it initializes the
3686<tt>va_list</tt> element the argument points to, so that the next call to
3687<tt>va_arg</tt> will produce the first variable argument passed to the function.
3688Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
3689last argument of the function, the compiler can figure that out.</p>
3690
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3691</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3692
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3693<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3694<div class="doc_subsubsection">
3695 <a name="i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
3696</div>
3697
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3698<div class="doc_text">
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3699<h5>Syntax:</h5>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]3700<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3701<h5>Overview:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3702
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3703<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>&lt;arglist&gt;</tt>
3704which has been initialized previously with <tt><a href="#i_va_start">llvm.va_start</a></tt>
3705or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3706
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3707<h5>Arguments:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3708
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3709<p>The argument is a <tt>va_list</tt> to destroy.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3710
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3711<h5>Semantics:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3712
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3713<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3714macro available in C. In a target-dependent way, it destroys the <tt>va_list</tt>.
3715Calls to <a href="#i_va_start"><tt>llvm.va_start</tt></a> and <a
3716 href="#i_va_copy"><tt>llvm.va_copy</tt></a> must be matched exactly
3717with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3718
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3719</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3720
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3721<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3722<div class="doc_subsubsection">
3723 <a name="i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
3724</div>
3725
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3726<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3727
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3728<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3729
3730<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]3731 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3732</pre>
3733
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3734<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3735
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3736<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position from
3737the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3738
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3739<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3740
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3741<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
Andrew Lenharth5305ea52005-06-22 20:38:11 +0000[diff] [blame]3742The second argument is a pointer to a <tt>va_list</tt> element to copy from.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3743
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3744
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3745<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3746
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3747<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt> macro
3748available in C. In a target-dependent way, it copies the source
3749<tt>va_list</tt> element into the destination list. This intrinsic is necessary
3750because the <tt><a href="i_va_begin">llvm.va_begin</a></tt> intrinsic may be
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3751arbitrarily complex and require memory allocation, for example.</p>
3752
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3753</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3754
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3755<!-- ======================================================================= -->
3756<div class="doc_subsection">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3757 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
3758</div>
3759
3760<div class="doc_text">
3761
3762<p>
3763LLVM support for <a href="GarbageCollection.html">Accurate Garbage
3764Collection</a> requires the implementation and generation of these intrinsics.
3765These intrinsics allow identification of <a href="#i_gcroot">GC roots on the
3766stack</a>, as well as garbage collector implementations that require <a
3767href="#i_gcread">read</a> and <a href="#i_gcwrite">write</a> barriers.
3768Front-ends for type-safe garbage collected languages should generate these
3769intrinsics to make use of the LLVM garbage collectors. For more details, see <a
3770href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
3771</p>
3772</div>
3773
3774<!-- _______________________________________________________________________ -->
3775<div class="doc_subsubsection">
3776 <a name="i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
3777</div>
3778
3779<div class="doc_text">
3780
3781<h5>Syntax:</h5>
3782
3783<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]3784 declare void @llvm.gcroot(&lt;ty&gt;** %ptrloc, &lt;ty2&gt;* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3785</pre>
3786
3787<h5>Overview:</h5>
3788
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]3789<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3790the code generator, and allows some metadata to be associated with it.</p>
3791
3792<h5>Arguments:</h5>
3793
3794<p>The first argument specifies the address of a stack object that contains the
3795root pointer. The second pointer (which must be either a constant or a global
3796value address) contains the meta-data to be associated with the root.</p>
3797
3798<h5>Semantics:</h5>
3799
3800<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
3801location. At compile-time, the code generator generates information to allow
3802the runtime to find the pointer at GC safe points.
3803</p>
3804
3805</div>
3806
3807
3808<!-- _______________________________________________________________________ -->
3809<div class="doc_subsubsection">
3810 <a name="i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
3811</div>
3812
3813<div class="doc_text">
3814
3815<h5>Syntax:</h5>
3816
3817<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]3818 declare i8 * @llvm.gcread(i8 * %ObjPtr, i8 ** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3819</pre>
3820
3821<h5>Overview:</h5>
3822
3823<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
3824locations, allowing garbage collector implementations that require read
3825barriers.</p>
3826
3827<h5>Arguments:</h5>
3828
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]3829<p>The second argument is the address to read from, which should be an address
3830allocated from the garbage collector. The first object is a pointer to the
3831start of the referenced object, if needed by the language runtime (otherwise
3832null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3833
3834<h5>Semantics:</h5>
3835
3836<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
3837instruction, but may be replaced with substantially more complex code by the
3838garbage collector runtime, as needed.</p>
3839
3840</div>
3841
3842
3843<!-- _______________________________________________________________________ -->
3844<div class="doc_subsubsection">
3845 <a name="i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
3846</div>
3847
3848<div class="doc_text">
3849
3850<h5>Syntax:</h5>
3851
3852<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]3853 declare void @llvm.gcwrite(i8 * %P1, i8 * %Obj, i8 ** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3854</pre>
3855
3856<h5>Overview:</h5>
3857
3858<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
3859locations, allowing garbage collector implementations that require write
3860barriers (such as generational or reference counting collectors).</p>
3861
3862<h5>Arguments:</h5>
3863
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]3864<p>The first argument is the reference to store, the second is the start of the
3865object to store it to, and the third is the address of the field of Obj to
3866store to. If the runtime does not require a pointer to the object, Obj may be
3867null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3868
3869<h5>Semantics:</h5>
3870
3871<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
3872instruction, but may be replaced with substantially more complex code by the
3873garbage collector runtime, as needed.</p>
3874
3875</div>
3876
3877
3878
3879<!-- ======================================================================= -->
3880<div class="doc_subsection">
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]3881 <a name="int_codegen">Code Generator Intrinsics</a>
3882</div>
3883
3884<div class="doc_text">
3885<p>
3886These intrinsics are provided by LLVM to expose special features that may only
3887be implemented with code generator support.
3888</p>
3889
3890</div>
3891
3892<!-- _______________________________________________________________________ -->
3893<div class="doc_subsubsection">
3894 <a name="i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
3895</div>
3896
3897<div class="doc_text">
3898
3899<h5>Syntax:</h5>
3900<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]3901 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]3902</pre>
3903
3904<h5>Overview:</h5>
3905
3906<p>
Chris Lattnerc1fb4262006-10-15 20:05:59 +0000[diff] [blame]3907The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
3908target-specific value indicating the return address of the current function
3909or one of its callers.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]3910</p>
3911
3912<h5>Arguments:</h5>
3913
3914<p>
3915The argument to this intrinsic indicates which function to return the address
3916for. Zero indicates the calling function, one indicates its caller, etc. The
3917argument is <b>required</b> to be a constant integer value.
3918</p>
3919
3920<h5>Semantics:</h5>
3921
3922<p>
3923The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
3924the return address of the specified call frame, or zero if it cannot be
3925identified. The value returned by this intrinsic is likely to be incorrect or 0
3926for arguments other than zero, so it should only be used for debugging purposes.
3927</p>
3928
3929<p>
3930Note that calling this intrinsic does not prevent function inlining or other
Chris Lattner2e6eb5f2005-03-07 20:30:51 +0000[diff] [blame]3931aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]3932source-language caller.
3933</p>
3934</div>
3935
3936
3937<!-- _______________________________________________________________________ -->
3938<div class="doc_subsubsection">
3939 <a name="i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
3940</div>
3941
3942<div class="doc_text">
3943
3944<h5>Syntax:</h5>
3945<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]3946 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]3947</pre>
3948
3949<h5>Overview:</h5>
3950
3951<p>
Chris Lattnerc1fb4262006-10-15 20:05:59 +0000[diff] [blame]3952The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
3953target-specific frame pointer value for the specified stack frame.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]3954</p>
3955
3956<h5>Arguments:</h5>
3957
3958<p>
3959The argument to this intrinsic indicates which function to return the frame
3960pointer for. Zero indicates the calling function, one indicates its caller,
3961etc. The argument is <b>required</b> to be a constant integer value.
3962</p>
3963
3964<h5>Semantics:</h5>
3965
3966<p>
3967The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
3968the frame address of the specified call frame, or zero if it cannot be
3969identified. The value returned by this intrinsic is likely to be incorrect or 0
3970for arguments other than zero, so it should only be used for debugging purposes.
3971</p>
3972
3973<p>
3974Note that calling this intrinsic does not prevent function inlining or other
Chris Lattner2e6eb5f2005-03-07 20:30:51 +0000[diff] [blame]3975aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]3976source-language caller.
3977</p>
3978</div>
3979
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]3980<!-- _______________________________________________________________________ -->
3981<div class="doc_subsubsection">
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]3982 <a name="i_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
3983</div>
3984
3985<div class="doc_text">
3986
3987<h5>Syntax:</h5>
3988<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]3989 declare i8 *@llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]3990</pre>
3991
3992<h5>Overview:</h5>
3993
3994<p>
3995The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
3996the function stack, for use with <a href="#i_stackrestore">
3997<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
3998features like scoped automatic variable sized arrays in C99.
3999</p>
4000
4001<h5>Semantics:</h5>
4002
4003<p>
4004This intrinsic returns a opaque pointer value that can be passed to <a
4005href="#i_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
4006<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
4007<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
4008state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
4009practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
4010that were allocated after the <tt>llvm.stacksave</tt> was executed.
4011</p>
4012
4013</div>
4014
4015<!-- _______________________________________________________________________ -->
4016<div class="doc_subsubsection">
4017 <a name="i_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
4018</div>
4019
4020<div class="doc_text">
4021
4022<h5>Syntax:</h5>
4023<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4024 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4025</pre>
4026
4027<h5>Overview:</h5>
4028
4029<p>
4030The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
4031the function stack to the state it was in when the corresponding <a
4032href="#llvm.stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
4033useful for implementing language features like scoped automatic variable sized
4034arrays in C99.
4035</p>
4036
4037<h5>Semantics:</h5>
4038
4039<p>
4040See the description for <a href="#i_stacksave"><tt>llvm.stacksave</tt></a>.
4041</p>
4042
4043</div>
4044
4045
4046<!-- _______________________________________________________________________ -->
4047<div class="doc_subsubsection">
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4048 <a name="i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
4049</div>
4050
4051<div class="doc_text">
4052
4053<h5>Syntax:</h5>
4054<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4055 declare void @llvm.prefetch(i8 * &lt;address&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4056 i32 &lt;rw&gt;, i32 &lt;locality&gt;)
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4057</pre>
4058
4059<h5>Overview:</h5>
4060
4061
4062<p>
4063The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4064a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
4065no
4066effect on the behavior of the program but can change its performance
Chris Lattnerff851072005-02-28 19:47:14 +0000[diff] [blame]4067characteristics.
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4068</p>
4069
4070<h5>Arguments:</h5>
4071
4072<p>
4073<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
4074determining if the fetch should be for a read (0) or write (1), and
4075<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattnerd3e641c2005-03-07 20:31:38 +0000[diff] [blame]4076locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4077<tt>locality</tt> arguments must be constant integers.
4078</p>
4079
4080<h5>Semantics:</h5>
4081
4082<p>
4083This intrinsic does not modify the behavior of the program. In particular,
4084prefetches cannot trap and do not produce a value. On targets that support this
4085intrinsic, the prefetch can provide hints to the processor cache for better
4086performance.
4087</p>
4088
4089</div>
4090
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4091<!-- _______________________________________________________________________ -->
4092<div class="doc_subsubsection">
4093 <a name="i_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
4094</div>
4095
4096<div class="doc_text">
4097
4098<h5>Syntax:</h5>
4099<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4100 declare void @llvm.pcmarker( i32 &lt;id&gt; )
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4101</pre>
4102
4103<h5>Overview:</h5>
4104
4105
4106<p>
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4107The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
4108(PC) in a region of
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4109code to simulators and other tools. The method is target specific, but it is
4110expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohendc6bfea2005-11-11 02:15:27 +0000[diff] [blame]4111The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnere64d41d2005-11-15 06:07:55 +0000[diff] [blame]4112after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb40261e2006-03-24 07:16:10 +0000[diff] [blame]4113optimizations. The intended use is to be inserted after optimizations to allow
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4114correlations of simulation runs.
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4115</p>
4116
4117<h5>Arguments:</h5>
4118
4119<p>
4120<tt>id</tt> is a numerical id identifying the marker.
4121</p>
4122
4123<h5>Semantics:</h5>
4124
4125<p>
4126This intrinsic does not modify the behavior of the program. Backends that do not
4127support this intrinisic may ignore it.
4128</p>
4129
4130</div>
4131
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]4132<!-- _______________________________________________________________________ -->
4133<div class="doc_subsubsection">
4134 <a name="i_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
4135</div>
4136
4137<div class="doc_text">
4138
4139<h5>Syntax:</h5>
4140<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4141 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]4142</pre>
4143
4144<h5>Overview:</h5>
4145
4146
4147<p>
4148The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
4149counter register (or similar low latency, high accuracy clocks) on those targets
4150that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
4151As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
4152should only be used for small timings.
4153</p>
4154
4155<h5>Semantics:</h5>
4156
4157<p>
4158When directly supported, reading the cycle counter should not modify any memory.
4159Implementations are allowed to either return a application specific value or a
4160system wide value. On backends without support, this is lowered to a constant 0.
4161</p>
4162
4163</div>
4164
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4165<!-- ======================================================================= -->
4166<div class="doc_subsection">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4167 <a name="int_libc">Standard C Library Intrinsics</a>
4168</div>
4169
4170<div class="doc_text">
4171<p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4172LLVM provides intrinsics for a few important standard C library functions.
4173These intrinsics allow source-language front-ends to pass information about the
4174alignment of the pointer arguments to the code generator, providing opportunity
4175for more efficient code generation.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4176</p>
4177
4178</div>
4179
4180<!-- _______________________________________________________________________ -->
4181<div class="doc_subsubsection">
4182 <a name="i_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
4183</div>
4184
4185<div class="doc_text">
4186
4187<h5>Syntax:</h5>
4188<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4189 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4190 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4191 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4192 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4193</pre>
4194
4195<h5>Overview:</h5>
4196
4197<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4198The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4199location to the destination location.
4200</p>
4201
4202<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4203Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4204intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4205</p>
4206
4207<h5>Arguments:</h5>
4208
4209<p>
4210The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4211the source. The third argument is an integer argument
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4212specifying the number of bytes to copy, and the fourth argument is the alignment
4213of the source and destination locations.
4214</p>
4215
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4216<p>
4217If the call to this intrinisic has an alignment value that is not 0 or 1, then
Chris Lattner5316e5d2006-03-04 00:02:10 +0000[diff] [blame]4218the caller guarantees that both the source and destination pointers are aligned
4219to that boundary.
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4220</p>
4221
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4222<h5>Semantics:</h5>
4223
4224<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4225The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4226location to the destination location, which are not allowed to overlap. It
4227copies "len" bytes of memory over. If the argument is known to be aligned to
4228some boundary, this can be specified as the fourth argument, otherwise it should
4229be set to 0 or 1.
4230</p>
4231</div>
4232
4233
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4234<!-- _______________________________________________________________________ -->
4235<div class="doc_subsubsection">
4236 <a name="i_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
4237</div>
4238
4239<div class="doc_text">
4240
4241<h5>Syntax:</h5>
4242<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4243 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4244 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4245 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4246 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4247</pre>
4248
4249<h5>Overview:</h5>
4250
4251<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4252The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
4253location to the destination location. It is similar to the
4254'<tt>llvm.memcmp</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4255</p>
4256
4257<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4258Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
4259intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4260</p>
4261
4262<h5>Arguments:</h5>
4263
4264<p>
4265The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4266the source. The third argument is an integer argument
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4267specifying the number of bytes to copy, and the fourth argument is the alignment
4268of the source and destination locations.
4269</p>
4270
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4271<p>
4272If the call to this intrinisic has an alignment value that is not 0 or 1, then
Chris Lattner5316e5d2006-03-04 00:02:10 +0000[diff] [blame]4273the caller guarantees that the source and destination pointers are aligned to
4274that boundary.
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4275</p>
4276
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4277<h5>Semantics:</h5>
4278
4279<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4280The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4281location to the destination location, which may overlap. It
4282copies "len" bytes of memory over. If the argument is known to be aligned to
4283some boundary, this can be specified as the fourth argument, otherwise it should
4284be set to 0 or 1.
4285</p>
4286</div>
4287
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4288
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4289<!-- _______________________________________________________________________ -->
4290<div class="doc_subsubsection">
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4291 <a name="i_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4292</div>
4293
4294<div class="doc_text">
4295
4296<h5>Syntax:</h5>
4297<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4298 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4299 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4300 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4301 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4302</pre>
4303
4304<h5>Overview:</h5>
4305
4306<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4307The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4308byte value.
4309</p>
4310
4311<p>
4312Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
4313does not return a value, and takes an extra alignment argument.
4314</p>
4315
4316<h5>Arguments:</h5>
4317
4318<p>
4319The first argument is a pointer to the destination to fill, the second is the
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4320byte value to fill it with, the third argument is an integer
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4321argument specifying the number of bytes to fill, and the fourth argument is the
4322known alignment of destination location.
4323</p>
4324
4325<p>
4326If the call to this intrinisic has an alignment value that is not 0 or 1, then
Chris Lattner5316e5d2006-03-04 00:02:10 +0000[diff] [blame]4327the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4328</p>
4329
4330<h5>Semantics:</h5>
4331
4332<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4333The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
4334the
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4335destination location. If the argument is known to be aligned to some boundary,
4336this can be specified as the fourth argument, otherwise it should be set to 0 or
43371.
4338</p>
4339</div>
4340
4341
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]4342<!-- _______________________________________________________________________ -->
4343<div class="doc_subsubsection">
Chris Lattner069b5bd2006-01-16 22:38:59 +0000[diff] [blame]4344 <a name="i_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4345</div>
4346
4347<div class="doc_text">
4348
4349<h5>Syntax:</h5>
4350<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4351 declare float @llvm.sqrt.f32(float %Val)
4352 declare double @llvm.sqrt.f64(double %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4353</pre>
4354
4355<h5>Overview:</h5>
4356
4357<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4358The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4359returning the same value as the libm '<tt>sqrt</tt>' function would. Unlike
4360<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
4361negative numbers (which allows for better optimization).
4362</p>
4363
4364<h5>Arguments:</h5>
4365
4366<p>
4367The argument and return value are floating point numbers of the same type.
4368</p>
4369
4370<h5>Semantics:</h5>
4371
4372<p>
4373This function returns the sqrt of the specified operand if it is a positive
4374floating point number.
4375</p>
4376</div>
4377
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4378<!-- _______________________________________________________________________ -->
4379<div class="doc_subsubsection">
4380 <a name="i_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
4381</div>
4382
4383<div class="doc_text">
4384
4385<h5>Syntax:</h5>
4386<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4387 declare float @llvm.powi.f32(float %Val, i32 %power)
4388 declare double @llvm.powi.f64(double %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4389</pre>
4390
4391<h5>Overview:</h5>
4392
4393<p>
4394The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
4395specified (positive or negative) power. The order of evaluation of
4396multiplications is not defined.
4397</p>
4398
4399<h5>Arguments:</h5>
4400
4401<p>
4402The second argument is an integer power, and the first is a value to raise to
4403that power.
4404</p>
4405
4406<h5>Semantics:</h5>
4407
4408<p>
4409This function returns the first value raised to the second power with an
4410unspecified sequence of rounding operations.</p>
4411</div>
4412
4413
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4414<!-- ======================================================================= -->
4415<div class="doc_subsection">
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4416 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4417</div>
4418
4419<div class="doc_text">
4420<p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4421LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4422These allow efficient code generation for some algorithms.
4423</p>
4424
4425</div>
4426
4427<!-- _______________________________________________________________________ -->
4428<div class="doc_subsubsection">
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4429 <a name="i_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
4430</div>
4431
4432<div class="doc_text">
4433
4434<h5>Syntax:</h5>
4435<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4436 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
4437 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
4438 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4439</pre>
4440
4441<h5>Overview:</h5>
4442
4443<p>
4444The '<tt>llvm.bwsap</tt>' family of intrinsics is used to byteswap a 16, 32 or
444564 bit quantity. These are useful for performing operations on data that is not
4446in the target's native byte order.
4447</p>
4448
4449<h5>Semantics:</h5>
4450
4451<p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4452The <tt>llvm.bswap.16</tt> intrinsic returns an i16 value that has the high
4453and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
4454intrinsic returns an i32 value that has the four bytes of the input i32
4455swapped, so that if the input bytes are numbered 0, 1, 2, 3 then the returned
4456i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i64</tt>
4457intrinsic extends this concept to 64 bits.
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4458</p>
4459
4460</div>
4461
4462<!-- _______________________________________________________________________ -->
4463<div class="doc_subsubsection">
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4464 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4465</div>
4466
4467<div class="doc_text">
4468
4469<h5>Syntax:</h5>
4470<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4471 declare i8 @llvm.ctpop.i8 (i8 &lt;src&gt;)
4472 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
4473 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
4474 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4475</pre>
4476
4477<h5>Overview:</h5>
4478
4479<p>
Chris Lattner069b5bd2006-01-16 22:38:59 +0000[diff] [blame]4480The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
4481value.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4482</p>
4483
4484<h5>Arguments:</h5>
4485
4486<p>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]4487The only argument is the value to be counted. The argument may be of any
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]4488integer type. The return type must match the argument type.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4489</p>
4490
4491<h5>Semantics:</h5>
4492
4493<p>
4494The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
4495</p>
4496</div>
4497
4498<!-- _______________________________________________________________________ -->
4499<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]4500 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4501</div>
4502
4503<div class="doc_text">
4504
4505<h5>Syntax:</h5>
4506<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4507 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
4508 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
4509 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
4510 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4511</pre>
4512
4513<h5>Overview:</h5>
4514
4515<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4516The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
4517leading zeros in a variable.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4518</p>
4519
4520<h5>Arguments:</h5>
4521
4522<p>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]4523The only argument is the value to be counted. The argument may be of any
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]4524integer type. The return type must match the argument type.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4525</p>
4526
4527<h5>Semantics:</h5>
4528
4529<p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4530The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
4531in a variable. If the src == 0 then the result is the size in bits of the type
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4532of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4533</p>
4534</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]4535
4536
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4537
4538<!-- _______________________________________________________________________ -->
4539<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]4540 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4541</div>
4542
4543<div class="doc_text">
4544
4545<h5>Syntax:</h5>
4546<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4547 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
4548 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
4549 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
4550 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4551</pre>
4552
4553<h5>Overview:</h5>
4554
4555<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4556The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
4557trailing zeros.
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4558</p>
4559
4560<h5>Arguments:</h5>
4561
4562<p>
4563The only argument is the value to be counted. The argument may be of any
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]4564integer type. The return type must match the argument type.
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4565</p>
4566
4567<h5>Semantics:</h5>
4568
4569<p>
4570The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
4571in a variable. If the src == 0 then the result is the size in bits of the type
4572of src. For example, <tt>llvm.cttz(2) = 1</tt>.
4573</p>
4574</div>
4575
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4576<!-- ======================================================================= -->
4577<div class="doc_subsection">
4578 <a name="int_debugger">Debugger Intrinsics</a>
4579</div>
4580
4581<div class="doc_text">
4582<p>
4583The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
4584are described in the <a
4585href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
4586Debugging</a> document.
4587</p>
4588</div>
4589
4590
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]4591<!-- ======================================================================= -->
4592<div class="doc_subsection">
4593 <a name="int_eh">Exception Handling Intrinsics</a>
4594</div>
4595
4596<div class="doc_text">
4597<p> The LLVM exception handling intrinsics (which all start with
4598<tt>llvm.eh.</tt> prefix), are described in the <a
4599href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
4600Handling</a> document. </p>
4601</div>
4602
4603
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4604<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4605<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]4606<address>
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4611
4612 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencerca058542006-03-14 05:39:39 +0000[diff] [blame]4613 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]4614 Last modified: $Date$
4615</address>
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