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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 91c284c0a63192655d6f1f0a226842956e1e9151 / . / docs / LangRef.html
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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 Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]14
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]15<div class="doc_title"> LLVM Language Reference Manual </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a></li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]24 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]25 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]26 <li><a href="#functionstructure">Functions</a></li>
Anton Korobeynikovc6c98af2007-04-29 18:02:48 +0000[diff] [blame]27 <li><a href="#aliasstructure">Aliases</a>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]28 <li><a href="#paramattrs">Parameter Attributes</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]29 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]30 <li><a href="#datalayout">Data Layout</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]31 </ol>
32 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]33 <li><a href="#typesystem">Type System</a>
34 <ol>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]35 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]36 <ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]37 <li><a href="#t_classifications">Type Classifications</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]38 </ol>
39 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]40 <li><a href="#t_derived">Derived Types</a>
41 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]42 <li><a href="#t_array">Array Type</a></li>
Misha Brukman9d0919f2003-11-08 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 Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]45 <li><a href="#t_struct">Structure Type</a></li>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]46 <li><a href="#t_pstruct">Packed Structure Type</a></li>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]47 <li><a href="#t_vector">Vector Type</a></li>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]48 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]49 </ol>
50 </li>
51 </ol>
52 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]53 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 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 Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]61 </li>
Chris Lattnere87d6532006-01-25 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 Lattner00950542001-06-06 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 Lattner261efe92003-11-25 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 Brukman9d0919f2003-11-08 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 Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]75 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]76 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]77 </ol>
78 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]79 <li><a href="#binaryops">Binary Operations</a>
80 <ol>
Chris Lattner261efe92003-11-25 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 Spencer1628cec2006-10-26 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 Spencer0a783f72006-11-02 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 Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]90 </ol>
91 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]92 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
93 <ol>
Reid Spencer8e11bf82007-02-02 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 Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]97 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]98 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]99 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]100 </ol>
101 </li>
Chris Lattner3df241e2006-04-08 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 Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]107 </ol>
108 </li>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]109 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]110 <ol>
Chris Lattner261efe92003-11-25 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 Bocchino7b81c752006-02-17 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 Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]117 </ol>
118 </li>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]119 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer9dee3ac2006-11-08 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 Spencerd4448792006-11-09 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 Spencer72679252006-11-11 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 Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]132 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]133 </ol>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]134 <li><a href="#otherops">Other Operations</a>
135 <ol>
Reid Spencerf3a70a62006-11-18 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 Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]138 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]139 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]140 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]141 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]142 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]143 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]144 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]145 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]146 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]147 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]148 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
149 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]150 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
151 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
152 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]153 </ol>
154 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]155 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
156 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]157 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
158 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
159 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]160 </ol>
161 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]162 <li><a href="#int_codegen">Code Generator Intrinsics</a>
163 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]164 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
165 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
166 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
167 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
168 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
169 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
170 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]171 </ol>
172 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]173 <li><a href="#int_libc">Standard C Library Intrinsics</a>
174 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]175 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
176 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
177 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
178 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
179 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame^]180 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
181 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
182 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]183 </ol>
184 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]185 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]186 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]187 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]188 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
189 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
190 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]191 <li><a href="#int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic </a></li>
192 <li><a href="#int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]193 </ol>
194 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]195 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]196 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]197 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]198 <ol>
199 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]200 </ol>
201 </li>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]202 <li><a href="#int_general">General intrinsics</a>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]203 <ol>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]204 <li><a href="#int_var_annotation">
Tanya Lattner91d0b882007-09-22 00:01:26 +0000[diff] [blame]205 <tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]206 </ol>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]207 <ol>
208 <li><a href="#int_annotation">
Tanya Lattner91d0b882007-09-22 00:01:26 +0000[diff] [blame]209 <tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]210 </ol>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]211 </li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]212 </ol>
213 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]214</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]215
216<div class="doc_author">
217 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
218 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]219</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]220
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]221<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]222<div class="doc_section"> <a name="abstract">Abstract </a></div>
223<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]224
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]225<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]226<p>This document is a reference manual for the LLVM assembly language.
227LLVM is an SSA based representation that provides type safety,
228low-level operations, flexibility, and the capability of representing
229'all' high-level languages cleanly. It is the common code
230representation used throughout all phases of the LLVM compilation
231strategy.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]232</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]233
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]234<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]235<div class="doc_section"> <a name="introduction">Introduction</a> </div>
236<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]237
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]238<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]239
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]240<p>The LLVM code representation is designed to be used in three
Gabor Greif04367bf2007-07-06 22:07:22 +0000[diff] [blame]241different forms: as an in-memory compiler IR, as an on-disk bitcode
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]242representation (suitable for fast loading by a Just-In-Time compiler),
243and as a human readable assembly language representation. This allows
244LLVM to provide a powerful intermediate representation for efficient
245compiler transformations and analysis, while providing a natural means
246to debug and visualize the transformations. The three different forms
247of LLVM are all equivalent. This document describes the human readable
248representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]249
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]250<p>The LLVM representation aims to be light-weight and low-level
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]251while being expressive, typed, and extensible at the same time. It
252aims to be a "universal IR" of sorts, by being at a low enough level
253that high-level ideas may be cleanly mapped to it (similar to how
254microprocessors are "universal IR's", allowing many source languages to
255be mapped to them). By providing type information, LLVM can be used as
256the target of optimizations: for example, through pointer analysis, it
257can be proven that a C automatic variable is never accessed outside of
258the current function... allowing it to be promoted to a simple SSA
259value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]260
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]261</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]262
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]263<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]264<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]265
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]266<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]267
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]268<p>It is important to note that this document describes 'well formed'
269LLVM assembly language. There is a difference between what the parser
270accepts and what is considered 'well formed'. For example, the
271following instruction is syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]272
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]273<div class="doc_code">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]274<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]275%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]276</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]277</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]278
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]279<p>...because the definition of <tt>%x</tt> does not dominate all of
280its uses. The LLVM infrastructure provides a verification pass that may
281be used to verify that an LLVM module is well formed. This pass is
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]282automatically run by the parser after parsing input assembly and by
Gabor Greif04367bf2007-07-06 22:07:22 +0000[diff] [blame]283the optimizer before it outputs bitcode. The violations pointed out
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]284by the verifier pass indicate bugs in transformation passes or input to
285the parser.</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]286</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]287
Chris Lattnercc689392007-10-03 17:34:29 +0000[diff] [blame]288<!-- Describe the typesetting conventions here. -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]289
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]290<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]291<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]292<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]293
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]294<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]295
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]296 <p>LLVM identifiers come in two basic types: global and local. Global
297 identifiers (functions, global variables) begin with the @ character. Local
298 identifiers (register names, types) begin with the % character. Additionally,
299 there are three different formats for identifiers, for different purposes:
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]300
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]301<ol>
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]302 <li>Named values are represented as a string of characters with their prefix.
303 For example, %foo, @DivisionByZero, %a.really.long.identifier. The actual
304 regular expression used is '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]305 Identifiers which require other characters in their names can be surrounded
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]306 with quotes. In this way, anything except a <tt>&quot;</tt> character can
307 be used in a named value.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]308
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]309 <li>Unnamed values are represented as an unsigned numeric value with their
310 prefix. For example, %12, @2, %44.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]311
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]312 <li>Constants, which are described in a <a href="#constants">section about
313 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]314</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]315
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]316<p>LLVM requires that values start with a prefix for two reasons: Compilers
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]317don't need to worry about name clashes with reserved words, and the set of
318reserved words may be expanded in the future without penalty. Additionally,
319unnamed identifiers allow a compiler to quickly come up with a temporary
320variable without having to avoid symbol table conflicts.</p>
321
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]322<p>Reserved words in LLVM are very similar to reserved words in other
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]323languages. There are keywords for different opcodes
324('<tt><a href="#i_add">add</a></tt>',
325 '<tt><a href="#i_bitcast">bitcast</a></tt>',
326 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]327href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]328and others. These reserved words cannot conflict with variable names, because
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]329none of them start with a prefix character ('%' or '@').</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]330
331<p>Here is an example of LLVM code to multiply the integer variable
332'<tt>%X</tt>' by 8:</p>
333
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]334<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]335
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]336<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]337<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]338%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]339</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]340</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]341
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]342<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]343
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]344<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]345<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]346%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]347</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]348</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]349
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]350<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]351
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]352<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]353<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]354<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
355<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
356%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]357</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]358</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]359
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]360<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
361important lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]362
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]363<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]364
365 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
366 line.</li>
367
368 <li>Unnamed temporaries are created when the result of a computation is not
369 assigned to a named value.</li>
370
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]371 <li>Unnamed temporaries are numbered sequentially</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]372
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]373</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]374
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]375<p>...and it also shows a convention that we follow in this document. When
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]376demonstrating instructions, we will follow an instruction with a comment that
377defines the type and name of value produced. Comments are shown in italic
378text.</p>
379
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]380</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]381
382<!-- *********************************************************************** -->
383<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
384<!-- *********************************************************************** -->
385
386<!-- ======================================================================= -->
387<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
388</div>
389
390<div class="doc_text">
391
392<p>LLVM programs are composed of "Module"s, each of which is a
393translation unit of the input programs. Each module consists of
394functions, global variables, and symbol table entries. Modules may be
395combined together with the LLVM linker, which merges function (and
396global variable) definitions, resolves forward declarations, and merges
397symbol table entries. Here is an example of the "hello world" module:</p>
398
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]399<div class="doc_code">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]400<pre><i>; Declare the string constant as a global constant...</i>
Chris Lattnera89e5f12007-06-12 17:00:26 +0000[diff] [blame]401<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
402 href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]403
404<i>; External declaration of the puts function</i>
Chris Lattnera89e5f12007-06-12 17:00:26 +0000[diff] [blame]405<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]406
407<i>; Definition of main function</i>
Chris Lattnera89e5f12007-06-12 17:00:26 +0000[diff] [blame]408define i32 @main() { <i>; i32()* </i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]409 <i>; Convert [13x i8 ]* to i8 *...</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]410 %cast210 = <a
Chris Lattner6c0955b2007-06-12 17:01:15 +0000[diff] [blame]411 href="#i_getelementptr">getelementptr</a> [13 x i8 ]* @.LC0, i64 0, i64 0 <i>; i8 *</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]412
413 <i>; Call puts function to write out the string to stdout...</i>
414 <a
Chris Lattnera89e5f12007-06-12 17:00:26 +0000[diff] [blame]415 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]416 <a
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]417 href="#i_ret">ret</a> i32 0<br>}<br>
418</pre>
419</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]420
421<p>This example is made up of a <a href="#globalvars">global variable</a>
422named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
423function, and a <a href="#functionstructure">function definition</a>
424for "<tt>main</tt>".</p>
425
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]426<p>In general, a module is made up of a list of global values,
427where both functions and global variables are global values. Global values are
428represented by a pointer to a memory location (in this case, a pointer to an
429array of char, and a pointer to a function), and have one of the following <a
430href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]431
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]432</div>
433
434<!-- ======================================================================= -->
435<div class="doc_subsection">
436 <a name="linkage">Linkage Types</a>
437</div>
438
439<div class="doc_text">
440
441<p>
442All Global Variables and Functions have one of the following types of linkage:
443</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]444
445<dl>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]446
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]447 <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]448
449 <dd>Global values with internal linkage are only directly accessible by
450 objects in the current module. In particular, linking code into a module with
451 an internal global value may cause the internal to be renamed as necessary to
452 avoid collisions. Because the symbol is internal to the module, all
453 references can be updated. This corresponds to the notion of the
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]454 '<tt>static</tt>' keyword in C.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]455 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]456
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]457 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]458
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]459 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
460 the same name when linkage occurs. This is typically used to implement
461 inline functions, templates, or other code which must be generated in each
462 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
463 allowed to be discarded.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]464 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]465
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]466 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]467
468 <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage,
469 except that unreferenced <tt>weak</tt> globals may not be discarded. This is
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]470 used for globals that may be emitted in multiple translation units, but that
471 are not guaranteed to be emitted into every translation unit that uses them.
472 One example of this are common globals in C, such as "<tt>int X;</tt>" at
473 global scope.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]474 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]475
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]476 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]477
478 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
479 pointer to array type. When two global variables with appending linkage are
480 linked together, the two global arrays are appended together. This is the
481 LLVM, typesafe, equivalent of having the system linker append together
482 "sections" with identical names when .o files are linked.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]483 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]484
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]485 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
486 <dd>The semantics of this linkage follow the ELF model: the symbol is weak
487 until linked, if not linked, the symbol becomes null instead of being an
488 undefined reference.
489 </dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]490
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]491 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]492
493 <dd>If none of the above identifiers are used, the global is externally
494 visible, meaning that it participates in linkage and can be used to resolve
495 external symbol references.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]496 </dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]497</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]498
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]499 <p>
500 The next two types of linkage are targeted for Microsoft Windows platform
501 only. They are designed to support importing (exporting) symbols from (to)
502 DLLs.
503 </p>
504
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]505 <dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]506 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
507
508 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
509 or variable via a global pointer to a pointer that is set up by the DLL
510 exporting the symbol. On Microsoft Windows targets, the pointer name is
511 formed by combining <code>_imp__</code> and the function or variable name.
512 </dd>
513
514 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
515
516 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
517 pointer to a pointer in a DLL, so that it can be referenced with the
518 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
519 name is formed by combining <code>_imp__</code> and the function or variable
520 name.
521 </dd>
522
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]523</dl>
524
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]525<p><a name="linkage_external"></a>For example, since the "<tt>.LC0</tt>"
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]526variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
527variable and was linked with this one, one of the two would be renamed,
528preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
529external (i.e., lacking any linkage declarations), they are accessible
Reid Spencerac8d2762007-01-05 00:59:10 +0000[diff] [blame]530outside of the current module.</p>
531<p>It is illegal for a function <i>declaration</i>
532to have any linkage type other than "externally visible", <tt>dllimport</tt>,
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]533or <tt>extern_weak</tt>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]534<p>Aliases can have only <tt>external</tt>, <tt>internal</tt> and <tt>weak</tt>
535linkages.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]536</div>
537
538<!-- ======================================================================= -->
539<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]540 <a name="callingconv">Calling Conventions</a>
541</div>
542
543<div class="doc_text">
544
545<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
546and <a href="#i_invoke">invokes</a> can all have an optional calling convention
547specified for the call. The calling convention of any pair of dynamic
548caller/callee must match, or the behavior of the program is undefined. The
549following calling conventions are supported by LLVM, and more may be added in
550the future:</p>
551
552<dl>
553 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
554
555 <dd>This calling convention (the default if no other calling convention is
556 specified) matches the target C calling conventions. This calling convention
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]557 supports varargs function calls and tolerates some mismatch in the declared
Reid Spencerc28d2bc2006-12-31 21:30:18 +0000[diff] [blame]558 prototype and implemented declaration of the function (as does normal C).
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]559 </dd>
560
561 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
562
563 <dd>This calling convention attempts to make calls as fast as possible
564 (e.g. by passing things in registers). This calling convention allows the
565 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner8cdc5bc2005-05-06 23:08:23 +0000[diff] [blame]566 without having to conform to an externally specified ABI. Implementations of
567 this convention should allow arbitrary tail call optimization to be supported.
568 This calling convention does not support varargs and requires the prototype of
569 all callees to exactly match the prototype of the function definition.
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]570 </dd>
571
572 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
573
574 <dd>This calling convention attempts to make code in the caller as efficient
575 as possible under the assumption that the call is not commonly executed. As
576 such, these calls often preserve all registers so that the call does not break
577 any live ranges in the caller side. This calling convention does not support
578 varargs and requires the prototype of all callees to exactly match the
579 prototype of the function definition.
580 </dd>
581
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]582 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]583
584 <dd>Any calling convention may be specified by number, allowing
585 target-specific calling conventions to be used. Target specific calling
586 conventions start at 64.
587 </dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]588</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]589
590<p>More calling conventions can be added/defined on an as-needed basis, to
591support pascal conventions or any other well-known target-independent
592convention.</p>
593
594</div>
595
596<!-- ======================================================================= -->
597<div class="doc_subsection">
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]598 <a name="visibility">Visibility Styles</a>
599</div>
600
601<div class="doc_text">
602
603<p>
604All Global Variables and Functions have one of the following visibility styles:
605</p>
606
607<dl>
608 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
609
610 <dd>On ELF, default visibility means that the declaration is visible to other
611 modules and, in shared libraries, means that the declared entity may be
612 overridden. On Darwin, default visibility means that the declaration is
613 visible to other modules. Default visibility corresponds to "external
614 linkage" in the language.
615 </dd>
616
617 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
618
619 <dd>Two declarations of an object with hidden visibility refer to the same
620 object if they are in the same shared object. Usually, hidden visibility
621 indicates that the symbol will not be placed into the dynamic symbol table,
622 so no other module (executable or shared library) can reference it
623 directly.
624 </dd>
625
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]626 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
627
628 <dd>On ELF, protected visibility indicates that the symbol will be placed in
629 the dynamic symbol table, but that references within the defining module will
630 bind to the local symbol. That is, the symbol cannot be overridden by another
631 module.
632 </dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]633</dl>
634
635</div>
636
637<!-- ======================================================================= -->
638<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]639 <a name="globalvars">Global Variables</a>
640</div>
641
642<div class="doc_text">
643
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]644<p>Global variables define regions of memory allocated at compilation time
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]645instead of run-time. Global variables may optionally be initialized, may have
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]646an explicit section to be placed in, and may have an optional explicit alignment
647specified. A variable may be defined as "thread_local", which means that it
648will not be shared by threads (each thread will have a separated copy of the
649variable). A variable may be defined as a global "constant," which indicates
650that the contents of the variable will <b>never</b> be modified (enabling better
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]651optimization, allowing the global data to be placed in the read-only section of
652an executable, etc). Note that variables that need runtime initialization
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]653cannot be marked "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]654
655<p>
656LLVM explicitly allows <em>declarations</em> of global variables to be marked
657constant, even if the final definition of the global is not. This capability
658can be used to enable slightly better optimization of the program, but requires
659the language definition to guarantee that optimizations based on the
660'constantness' are valid for the translation units that do not include the
661definition.
662</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]663
664<p>As SSA values, global variables define pointer values that are in
665scope (i.e. they dominate) all basic blocks in the program. Global
666variables always define a pointer to their "content" type because they
667describe a region of memory, and all memory objects in LLVM are
668accessed through pointers.</p>
669
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]670<p>LLVM allows an explicit section to be specified for globals. If the target
671supports it, it will emit globals to the section specified.</p>
672
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]673<p>An explicit alignment may be specified for a global. If not present, or if
674the alignment is set to zero, the alignment of the global is set by the target
675to whatever it feels convenient. If an explicit alignment is specified, the
676global is forced to have at least that much alignment. All alignments must be
677a power of 2.</p>
678
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]679<p>For example, the following defines a global with an initializer, section,
680 and alignment:</p>
681
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]682<div class="doc_code">
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]683<pre>
Chris Lattner3e63a9d2007-07-13 20:01:46 +0000[diff] [blame]684@G = constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]685</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]686</div>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]687
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]688</div>
689
690
691<!-- ======================================================================= -->
692<div class="doc_subsection">
693 <a name="functionstructure">Functions</a>
694</div>
695
696<div class="doc_text">
697
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]698<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
699an optional <a href="#linkage">linkage type</a>, an optional
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]700<a href="#visibility">visibility style</a>, an optional
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]701<a href="#callingconv">calling convention</a>, a return type, an optional
702<a href="#paramattrs">parameter attribute</a> for the return type, a function
703name, a (possibly empty) argument list (each with optional
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]704<a href="#paramattrs">parameter attributes</a>), an optional section, an
705optional alignment, an opening curly brace, a list of basic blocks, and a
706closing curly brace.
707
708LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
709optional <a href="#linkage">linkage type</a>, an optional
710<a href="#visibility">visibility style</a>, an optional
711<a href="#callingconv">calling convention</a>, a return type, an optional
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]712<a href="#paramattrs">parameter attribute</a> for the return type, a function
713name, a possibly empty list of arguments, and an optional alignment.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]714
715<p>A function definition contains a list of basic blocks, forming the CFG for
716the function. Each basic block may optionally start with a label (giving the
717basic block a symbol table entry), contains a list of instructions, and ends
718with a <a href="#terminators">terminator</a> instruction (such as a branch or
719function return).</p>
720
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]721<p>The first basic block in a function is special in two ways: it is immediately
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]722executed on entrance to the function, and it is not allowed to have predecessor
723basic blocks (i.e. there can not be any branches to the entry block of a
724function). Because the block can have no predecessors, it also cannot have any
725<a href="#i_phi">PHI nodes</a>.</p>
726
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]727<p>LLVM allows an explicit section to be specified for functions. If the target
728supports it, it will emit functions to the section specified.</p>
729
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]730<p>An explicit alignment may be specified for a function. If not present, or if
731the alignment is set to zero, the alignment of the function is set by the target
732to whatever it feels convenient. If an explicit alignment is specified, the
733function is forced to have at least that much alignment. All alignments must be
734a power of 2.</p>
735
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]736</div>
737
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]738
739<!-- ======================================================================= -->
740<div class="doc_subsection">
741 <a name="aliasstructure">Aliases</a>
742</div>
743<div class="doc_text">
744 <p>Aliases act as "second name" for the aliasee value (which can be either
Anton Korobeynikova80e1182007-04-28 13:45:00 +0000[diff] [blame]745 function or global variable or bitcast of global value). Aliases may have an
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]746 optional <a href="#linkage">linkage type</a>, and an
747 optional <a href="#visibility">visibility style</a>.</p>
748
749 <h5>Syntax:</h5>
750
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]751<div class="doc_code">
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]752<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]753@&lt;Name&gt; = [Linkage] [Visibility] alias &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]754</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]755</div>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]756
757</div>
758
759
760
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]761<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]762<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
763<div class="doc_text">
764 <p>The return type and each parameter of a function type may have a set of
765 <i>parameter attributes</i> associated with them. Parameter attributes are
766 used to communicate additional information about the result or parameters of
767 a function. Parameter attributes are considered to be part of the function
768 type so two functions types that differ only by the parameter attributes
769 are different function types.</p>
770
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]771 <p>Parameter attributes are simple keywords that follow the type specified. If
772 multiple parameter attributes are needed, they are space separated. For
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]773 example:</p>
774
775<div class="doc_code">
776<pre>
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]777%someFunc = i16 (i8 signext %someParam) zeroext
778%someFunc = i16 (i8 zeroext %someParam) zeroext
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]779</pre>
780</div>
781
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]782 <p>Note that the two function types above are unique because the parameter has
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]783 a different attribute (<tt>signext</tt> in the first one, <tt>zeroext</tt> in
784 the second). Also note that the attribute for the function result
785 (<tt>zeroext</tt>) comes immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]786
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]787 <p>Currently, only the following parameter attributes are defined:</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]788 <dl>
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]789 <dt><tt>zeroext</tt></dt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]790 <dd>This indicates that the parameter should be zero extended just before
791 a call to this function.</dd>
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]792 <dt><tt>signext</tt></dt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]793 <dd>This indicates that the parameter should be sign extended just before
794 a call to this function.</dd>
Anton Korobeynikov34d6dea2007-01-28 14:30:45 +0000[diff] [blame]795 <dt><tt>inreg</tt></dt>
796 <dd>This indicates that the parameter should be placed in register (if
Anton Korobeynikov66a8c8c2007-01-28 15:27:21 +0000[diff] [blame]797 possible) during assembling function call. Support for this attribute is
798 target-specific</dd>
Anton Korobeynikov34d6dea2007-01-28 14:30:45 +0000[diff] [blame]799 <dt><tt>sret</tt></dt>
Anton Korobeynikov66a8c8c2007-01-28 15:27:21 +0000[diff] [blame]800 <dd>This indicates that the parameter specifies the address of a structure
Reid Spencer67606122007-03-22 02:02:11 +0000[diff] [blame]801 that is the return value of the function in the source program.</dd>
Zhou Shengfebca342007-06-05 05:28:26 +0000[diff] [blame]802 <dt><tt>noalias</tt></dt>
803 <dd>This indicates that the parameter not alias any other object or any
804 other "noalias" objects during the function call.
Reid Spencer2dc52012007-03-22 02:18:56 +0000[diff] [blame]805 <dt><tt>noreturn</tt></dt>
806 <dd>This function attribute indicates that the function never returns. This
807 indicates to LLVM that every call to this function should be treated as if
808 an <tt>unreachable</tt> instruction immediately followed the call.</dd>
Reid Spencer67606122007-03-22 02:02:11 +0000[diff] [blame]809 <dt><tt>nounwind</tt></dt>
810 <dd>This function attribute indicates that the function type does not use
811 the unwind instruction and does not allow stack unwinding to propagate
812 through it.</dd>
Duncan Sands50f19f52007-07-27 19:57:41 +0000[diff] [blame]813 <dt><tt>nest</tt></dt>
814 <dd>This indicates that the parameter can be excised using the
815 <a href="#int_trampoline">trampoline intrinsics</a>.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]816 </dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]817
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]818</div>
819
820<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]821<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]822 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]823</div>
824
825<div class="doc_text">
826<p>
827Modules may contain "module-level inline asm" blocks, which corresponds to the
828GCC "file scope inline asm" blocks. These blocks are internally concatenated by
829LLVM and treated as a single unit, but may be separated in the .ll file if
830desired. The syntax is very simple:
831</p>
832
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]833<div class="doc_code">
834<pre>
835module asm "inline asm code goes here"
836module asm "more can go here"
837</pre>
838</div>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]839
840<p>The strings can contain any character by escaping non-printable characters.
841 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
842 for the number.
843</p>
844
845<p>
846 The inline asm code is simply printed to the machine code .s file when
847 assembly code is generated.
848</p>
849</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]850
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]851<!-- ======================================================================= -->
852<div class="doc_subsection">
853 <a name="datalayout">Data Layout</a>
854</div>
855
856<div class="doc_text">
857<p>A module may specify a target specific data layout string that specifies how
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]858data is to be laid out in memory. The syntax for the data layout is simply:</p>
859<pre> target datalayout = "<i>layout specification</i>"</pre>
860<p>The <i>layout specification</i> consists of a list of specifications
861separated by the minus sign character ('-'). Each specification starts with a
862letter and may include other information after the letter to define some
863aspect of the data layout. The specifications accepted are as follows: </p>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]864<dl>
865 <dt><tt>E</tt></dt>
866 <dd>Specifies that the target lays out data in big-endian form. That is, the
867 bits with the most significance have the lowest address location.</dd>
868 <dt><tt>e</tt></dt>
869 <dd>Specifies that hte target lays out data in little-endian form. That is,
870 the bits with the least significance have the lowest address location.</dd>
871 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
872 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
873 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
874 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
875 too.</dd>
876 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
877 <dd>This specifies the alignment for an integer type of a given bit
878 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
879 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
880 <dd>This specifies the alignment for a vector type of a given bit
881 <i>size</i>.</dd>
882 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
883 <dd>This specifies the alignment for a floating point type of a given bit
884 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
885 (double).</dd>
886 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
887 <dd>This specifies the alignment for an aggregate type of a given bit
888 <i>size</i>.</dd>
889</dl>
890<p>When constructing the data layout for a given target, LLVM starts with a
891default set of specifications which are then (possibly) overriden by the
892specifications in the <tt>datalayout</tt> keyword. The default specifications
893are given in this list:</p>
894<ul>
895 <li><tt>E</tt> - big endian</li>
896 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
897 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
898 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
899 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
900 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
901 <li><tt>i64:32:64</tt> - i64 has abi alignment of 32-bits but preferred
902 alignment of 64-bits</li>
903 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
904 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
905 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
906 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
907 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
908</ul>
909<p>When llvm is determining the alignment for a given type, it uses the
910following rules:
911<ol>
912 <li>If the type sought is an exact match for one of the specifications, that
913 specification is used.</li>
914 <li>If no match is found, and the type sought is an integer type, then the
915 smallest integer type that is larger than the bitwidth of the sought type is
916 used. If none of the specifications are larger than the bitwidth then the the
917 largest integer type is used. For example, given the default specifications
918 above, the i7 type will use the alignment of i8 (next largest) while both
919 i65 and i256 will use the alignment of i64 (largest specified).</li>
920 <li>If no match is found, and the type sought is a vector type, then the
921 largest vector type that is smaller than the sought vector type will be used
922 as a fall back. This happens because <128 x double> can be implemented in
923 terms of 64 <2 x double>, for example.</li>
924</ol>
925</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]926
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]927<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]928<div class="doc_section"> <a name="typesystem">Type System</a> </div>
929<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]930
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]931<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]932
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]933<p>The LLVM type system is one of the most important features of the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]934intermediate representation. Being typed enables a number of
935optimizations to be performed on the IR directly, without having to do
936extra analyses on the side before the transformation. A strong type
937system makes it easier to read the generated code and enables novel
938analyses and transformations that are not feasible to perform on normal
939three address code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]940
941</div>
942
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]943<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]944<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]945<div class="doc_text">
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]946<p>The primitive types are the fundamental building blocks of the LLVM
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]947system. The current set of primitive types is as follows:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]948
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]949<table class="layout">
950 <tr class="layout">
951 <td class="left">
952 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]953 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]954 <tr><th>Type</th><th>Description</th></tr>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]955 <tr><td><tt><a name="t_void">void</a></tt></td><td>No value</td></tr>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]956 <tr><td><tt>label</tt></td><td>Branch destination</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]957 </tbody>
958 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]959 </td>
960 <td class="right">
961 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]962 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]963 <tr><th>Type</th><th>Description</th></tr>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]964 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]965 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]966 </tbody>
967 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]968 </td>
969 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]970</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]971</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]972
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]973<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]974<div class="doc_subsubsection"> <a name="t_classifications">Type
975Classifications</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]976<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]977<p>These different primitive types fall into a few useful
978classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]979
980<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]981 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]982 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]983 <tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]984 <td><a name="t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]985 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]986 </tr>
987 <tr>
988 <td><a name="t_floating">floating point</a></td>
989 <td><tt>float, double</tt></td>
990 </tr>
991 <tr>
992 <td><a name="t_firstclass">first class</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]993 <td><tt>i1, ..., float, double, <br/>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]994 <a href="#t_pointer">pointer</a>,<a href="#t_vector">vector</a></tt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]995 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]996 </tr>
997 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]998</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]999
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1000<p>The <a href="#t_firstclass">first class</a> types are perhaps the
1001most important. Values of these types are the only ones which can be
1002produced by instructions, passed as arguments, or used as operands to
1003instructions. This means that all structures and arrays must be
1004manipulated either by pointer or by component.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1005</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1006
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1007<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1008<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1009
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1010<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1011
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1012<p>The real power in LLVM comes from the derived types in the system.
1013This is what allows a programmer to represent arrays, functions,
1014pointers, and other useful types. Note that these derived types may be
1015recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1016
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1017</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1018
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1019<!-- _______________________________________________________________________ -->
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1020<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1021
1022<div class="doc_text">
1023
1024<h5>Overview:</h5>
1025<p>The integer type is a very simple derived type that simply specifies an
1026arbitrary bit width for the integer type desired. Any bit width from 1 bit to
10272^23-1 (about 8 million) can be specified.</p>
1028
1029<h5>Syntax:</h5>
1030
1031<pre>
1032 iN
1033</pre>
1034
1035<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1036value.</p>
1037
1038<h5>Examples:</h5>
1039<table class="layout">
1040 <tr class="layout">
1041 <td class="left">
1042 <tt>i1</tt><br/>
1043 <tt>i4</tt><br/>
1044 <tt>i8</tt><br/>
1045 <tt>i16</tt><br/>
1046 <tt>i32</tt><br/>
1047 <tt>i42</tt><br/>
1048 <tt>i64</tt><br/>
1049 <tt>i1942652</tt><br/>
1050 </td>
1051 <td class="left">
1052 A boolean integer of 1 bit<br/>
1053 A nibble sized integer of 4 bits.<br/>
1054 A byte sized integer of 8 bits.<br/>
1055 A half word sized integer of 16 bits.<br/>
1056 A word sized integer of 32 bits.<br/>
1057 An integer whose bit width is the answer. <br/>
1058 A double word sized integer of 64 bits.<br/>
1059 A really big integer of over 1 million bits.<br/>
1060 </td>
1061 </tr>
1062</table>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1063</div>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1064
1065<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1066<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1067
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1068<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1069
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1070<h5>Overview:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1071
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1072<p>The array type is a very simple derived type that arranges elements
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1073sequentially in memory. The array type requires a size (number of
1074elements) and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1075
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1076<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1077
1078<pre>
1079 [&lt;# elements&gt; x &lt;elementtype&gt;]
1080</pre>
1081
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1082<p>The number of elements is a constant integer value; elementtype may
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1083be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1084
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1085<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1086<table class="layout">
1087 <tr class="layout">
1088 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1089 <tt>[40 x i32 ]</tt><br/>
1090 <tt>[41 x i32 ]</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1091 <tt>[40 x i8]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1092 </td>
1093 <td class="left">
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1094 Array of 40 32-bit integer values.<br/>
1095 Array of 41 32-bit integer values.<br/>
1096 Array of 40 8-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1097 </td>
1098 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1099</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1100<p>Here are some examples of multidimensional arrays:</p>
1101<table class="layout">
1102 <tr class="layout">
1103 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1104 <tt>[3 x [4 x i32]]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1105 <tt>[12 x [10 x float]]</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1106 <tt>[2 x [3 x [4 x i16]]]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1107 </td>
1108 <td class="left">
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1109 3x4 array of 32-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1110 12x10 array of single precision floating point values.<br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1111 2x3x4 array of 16-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1112 </td>
1113 </tr>
1114</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1115
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1116<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1117length array. Normally, accesses past the end of an array are undefined in
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1118LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1119As a special case, however, zero length arrays are recognized to be variable
1120length. This allows implementation of 'pascal style arrays' with the LLVM
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1121type "{ i32, [0 x float]}", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1122
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1123</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1124
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1125<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1126<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1127<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1128<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1129<p>The function type can be thought of as a function signature. It
1130consists of a return type and a list of formal parameter types.
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]1131Function types are usually used to build virtual function tables
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1132(which are structures of pointers to functions), for indirect function
1133calls, and when defining a function.</p>
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]1134<p>
1135The return type of a function type cannot be an aggregate type.
1136</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1137<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1138<pre> &lt;returntype&gt; (&lt;parameter list&gt;)<br></pre>
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1139<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]1140specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1141which indicates that the function takes a variable number of arguments.
1142Variable argument functions can access their arguments with the <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1143 href="#int_varargs">variable argument handling intrinsic</a> functions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1144<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1145<table class="layout">
1146 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1147 <td class="left"><tt>i32 (i32)</tt></td>
1148 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1149 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1150 </tr><tr class="layout">
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]1151 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1152 </tt></td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1153 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1154 an <tt>i16</tt> that should be sign extended and a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1155 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1156 <tt>float</tt>.
1157 </td>
1158 </tr><tr class="layout">
1159 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1160 <td class="left">A vararg function that takes at least one
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1161 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1162 which returns an integer. This is the signature for <tt>printf</tt> in
1163 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1164 </td>
1165 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1166</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1167
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1168</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1169<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1170<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1171<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1172<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1173<p>The structure type is used to represent a collection of data members
1174together in memory. The packing of the field types is defined to match
1175the ABI of the underlying processor. The elements of a structure may
1176be any type that has a size.</p>
1177<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1178and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1179field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1180instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1181<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1182<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1183<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1184<table class="layout">
1185 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1186 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1187 <td class="left">A triple of three <tt>i32</tt> values</td>
1188 </tr><tr class="layout">
1189 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1190 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1191 second element is a <a href="#t_pointer">pointer</a> to a
1192 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1193 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1194 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1195</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1196</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1197
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1198<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1199<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1200</div>
1201<div class="doc_text">
1202<h5>Overview:</h5>
1203<p>The packed structure type is used to represent a collection of data members
1204together in memory. There is no padding between fields. Further, the alignment
1205of a packed structure is 1 byte. The elements of a packed structure may
1206be any type that has a size.</p>
1207<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1208and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1209field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1210instruction.</p>
1211<h5>Syntax:</h5>
1212<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1213<h5>Examples:</h5>
1214<table class="layout">
1215 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1216 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1217 <td class="left">A triple of three <tt>i32</tt> values</td>
1218 </tr><tr class="layout">
1219 <td class="left"><tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}&nbsp;&gt;</tt></td>
1220 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1221 second element is a <a href="#t_pointer">pointer</a> to a
1222 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1223 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1224 </tr>
1225</table>
1226</div>
1227
1228<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1229<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1230<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1231<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1232<p>As in many languages, the pointer type represents a pointer or
1233reference to another object, which must live in memory.</p>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1234<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1235<pre> &lt;type&gt; *<br></pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1236<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1237<table class="layout">
1238 <tr class="layout">
1239 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1240 <tt>[4x i32]*</tt><br/>
1241 <tt>i32 (i32 *) *</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1242 </td>
1243 <td class="left">
1244 A <a href="#t_pointer">pointer</a> to <a href="#t_array">array</a> of
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1245 four <tt>i32</tt> values<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1246 A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1247 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
1248 <tt>i32</tt>.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1249 </td>
1250 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1251</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1252</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1253
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1254<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1255<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1256<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1257
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1258<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1259
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1260<p>A vector type is a simple derived type that represents a vector
1261of elements. Vector types are used when multiple primitive data
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1262are operated in parallel using a single instruction (SIMD).
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1263A vector type requires a size (number of
Chris Lattnerb8d172f2005-11-10 01:44:22 +0000[diff] [blame]1264elements) and an underlying primitive data type. Vectors must have a power
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1265of two length (1, 2, 4, 8, 16 ...). Vector types are
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1266considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1267
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1268<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1269
1270<pre>
1271 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1272</pre>
1273
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1274<p>The number of elements is a constant integer value; elementtype may
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]1275be any integer or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1276
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1277<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1278
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1279<table class="layout">
1280 <tr class="layout">
1281 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1282 <tt>&lt;4 x i32&gt;</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1283 <tt>&lt;8 x float&gt;</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1284 <tt>&lt;2 x i64&gt;</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1285 </td>
1286 <td class="left">
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1287 Vector of 4 32-bit integer values.<br/>
1288 Vector of 8 floating-point values.<br/>
1289 Vector of 2 64-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1290 </td>
1291 </tr>
1292</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1293</div>
1294
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1295<!-- _______________________________________________________________________ -->
1296<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1297<div class="doc_text">
1298
1299<h5>Overview:</h5>
1300
1301<p>Opaque types are used to represent unknown types in the system. This
Gordon Henriksen8ac04ff2007-10-14 00:34:53 +0000[diff] [blame]1302corresponds (for example) to the C notion of a forward declared structure type.
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1303In LLVM, opaque types can eventually be resolved to any type (not just a
1304structure type).</p>
1305
1306<h5>Syntax:</h5>
1307
1308<pre>
1309 opaque
1310</pre>
1311
1312<h5>Examples:</h5>
1313
1314<table class="layout">
1315 <tr class="layout">
1316 <td class="left">
1317 <tt>opaque</tt>
1318 </td>
1319 <td class="left">
1320 An opaque type.<br/>
1321 </td>
1322 </tr>
1323</table>
1324</div>
1325
1326
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1327<!-- *********************************************************************** -->
1328<div class="doc_section"> <a name="constants">Constants</a> </div>
1329<!-- *********************************************************************** -->
1330
1331<div class="doc_text">
1332
1333<p>LLVM has several different basic types of constants. This section describes
1334them all and their syntax.</p>
1335
1336</div>
1337
1338<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1339<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1340
1341<div class="doc_text">
1342
1343<dl>
1344 <dt><b>Boolean constants</b></dt>
1345
1346 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1347 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1348 </dd>
1349
1350 <dt><b>Integer constants</b></dt>
1351
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1352 <dd>Standard integers (such as '4') are constants of the <a
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1353 href="#t_integer">integer</a> type. Negative numbers may be used with
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1354 integer types.
1355 </dd>
1356
1357 <dt><b>Floating point constants</b></dt>
1358
1359 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1360 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1361 notation (see below). Floating point constants must have a <a
1362 href="#t_floating">floating point</a> type. </dd>
1363
1364 <dt><b>Null pointer constants</b></dt>
1365
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1366 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1367 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1368
1369</dl>
1370
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1371<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1372of floating point constants. For example, the form '<tt>double
13730x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
13744.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1375(and the only time that they are generated by the disassembler) is when a
1376floating point constant must be emitted but it cannot be represented as a
1377decimal floating point number. For example, NaN's, infinities, and other
1378special values are represented in their IEEE hexadecimal format so that
1379assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1380
1381</div>
1382
1383<!-- ======================================================================= -->
1384<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1385</div>
1386
1387<div class="doc_text">
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1388<p>Aggregate constants arise from aggregation of simple constants
1389and smaller aggregate constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1390
1391<dl>
1392 <dt><b>Structure constants</b></dt>
1393
1394 <dd>Structure constants are represented with notation similar to structure
1395 type definitions (a comma separated list of elements, surrounded by braces
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1396 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* %G }</tt>",
Chris Lattner3e63a9d2007-07-13 20:01:46 +0000[diff] [blame]1397 where "<tt>%G</tt>" is declared as "<tt>@G = external global i32</tt>". Structure constants
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1398 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1399 types of elements must match those specified by the type.
1400 </dd>
1401
1402 <dt><b>Array constants</b></dt>
1403
1404 <dd>Array constants are represented with notation similar to array type
1405 definitions (a comma separated list of elements, surrounded by square brackets
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1406 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1407 constants must have <a href="#t_array">array type</a>, and the number and
1408 types of elements must match those specified by the type.
1409 </dd>
1410
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1411 <dt><b>Vector constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1412
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1413 <dd>Vector constants are represented with notation similar to vector type
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1414 definitions (a comma separated list of elements, surrounded by
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1415 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32 42,
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1416 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1417 href="#t_vector">vector type</a>, and the number and types of elements must
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1418 match those specified by the type.
1419 </dd>
1420
1421 <dt><b>Zero initialization</b></dt>
1422
1423 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1424 value to zero of <em>any</em> type, including scalar and aggregate types.
1425 This is often used to avoid having to print large zero initializers (e.g. for
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1426 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1427 initializers.
1428 </dd>
1429</dl>
1430
1431</div>
1432
1433<!-- ======================================================================= -->
1434<div class="doc_subsection">
1435 <a name="globalconstants">Global Variable and Function Addresses</a>
1436</div>
1437
1438<div class="doc_text">
1439
1440<p>The addresses of <a href="#globalvars">global variables</a> and <a
1441href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1442constants. These constants are explicitly referenced when the <a
1443href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1444href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1445file:</p>
1446
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1447<div class="doc_code">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1448<pre>
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]1449@X = global i32 17
1450@Y = global i32 42
1451@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1452</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1453</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1454
1455</div>
1456
1457<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1458<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1459<div class="doc_text">
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1460 <p>The string '<tt>undef</tt>' is recognized as a type-less constant that has
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1461 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1462 a constant is permitted.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1463
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1464 <p>Undefined values indicate to the compiler that the program is well defined
1465 no matter what value is used, giving the compiler more freedom to optimize.
1466 </p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1467</div>
1468
1469<!-- ======================================================================= -->
1470<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1471</div>
1472
1473<div class="doc_text">
1474
1475<p>Constant expressions are used to allow expressions involving other constants
1476to be used as constants. Constant expressions may be of any <a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1477href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1478that does not have side effects (e.g. load and call are not supported). The
1479following is the syntax for constant expressions:</p>
1480
1481<dl>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1482 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1483 <dd>Truncate a constant to another type. The bit size of CST must be larger
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]1484 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1485
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1486 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1487 <dd>Zero extend a constant to another type. The bit size of CST must be
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]1488 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1489
1490 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1491 <dd>Sign extend a constant to another type. The bit size of CST must be
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]1492 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1493
1494 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1495 <dd>Truncate a floating point constant to another floating point type. The
1496 size of CST must be larger than the size of TYPE. Both types must be
1497 floating point.</dd>
1498
1499 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1500 <dd>Floating point extend a constant to another type. The size of CST must be
1501 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1502
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]1503 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1504 <dd>Convert a floating point constant to the corresponding unsigned integer
1505 constant. TYPE must be an integer type. CST must be floating point. If the
1506 value won't fit in the integer type, the results are undefined.</dd>
1507
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1508 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1509 <dd>Convert a floating point constant to the corresponding signed integer
1510 constant. TYPE must be an integer type. CST must be floating point. If the
1511 value won't fit in the integer type, the results are undefined.</dd>
1512
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1513 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1514 <dd>Convert an unsigned integer constant to the corresponding floating point
1515 constant. TYPE must be floating point. CST must be of integer type. If the
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]1516 value won't fit in the floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1517
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1518 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1519 <dd>Convert a signed integer constant to the corresponding floating point
1520 constant. TYPE must be floating point. CST must be of integer type. If the
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]1521 value won't fit in the floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1522
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]1523 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1524 <dd>Convert a pointer typed constant to the corresponding integer constant
1525 TYPE must be an integer type. CST must be of pointer type. The CST value is
1526 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1527
1528 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1529 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1530 pointer type. CST must be of integer type. The CST value is zero extended,
1531 truncated, or unchanged to make it fit in a pointer size. This one is
1532 <i>really</i> dangerous!</dd>
1533
1534 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1535 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1536 identical (same number of bits). The conversion is done as if the CST value
1537 was stored to memory and read back as TYPE. In other words, no bits change
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]1538 with this operator, just the type. This can be used for conversion of
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1539 vector types to any other type, as long as they have the same bit width. For
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]1540 pointers it is only valid to cast to another pointer type.
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1541 </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1542
1543 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1544
1545 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1546 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1547 instruction, the index list may have zero or more indexes, which are required
1548 to make sense for the type of "CSTPTR".</dd>
1549
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1550 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1551
1552 <dd>Perform the <a href="#i_select">select operation</a> on
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1553 constants.</dd>
1554
1555 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1556 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1557
1558 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1559 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1560
1561 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1562
1563 <dd>Perform the <a href="#i_extractelement">extractelement
1564 operation</a> on constants.
1565
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1566 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1567
1568 <dd>Perform the <a href="#i_insertelement">insertelement
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1569 operation</a> on constants.</dd>
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1570
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1571
1572 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1573
1574 <dd>Perform the <a href="#i_shufflevector">shufflevector
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1575 operation</a> on constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1576
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1577 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1578
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1579 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1580 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1581 binary</a> operations. The constraints on operands are the same as those for
1582 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1583 values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1584</dl>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1585</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]1586
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1587<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1588<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1589<!-- *********************************************************************** -->
1590
1591<!-- ======================================================================= -->
1592<div class="doc_subsection">
1593<a name="inlineasm">Inline Assembler Expressions</a>
1594</div>
1595
1596<div class="doc_text">
1597
1598<p>
1599LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1600Module-Level Inline Assembly</a>) through the use of a special value. This
1601value represents the inline assembler as a string (containing the instructions
1602to emit), a list of operand constraints (stored as a string), and a flag that
1603indicates whether or not the inline asm expression has side effects. An example
1604inline assembler expression is:
1605</p>
1606
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1607<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1608<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1609i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1610</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1611</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1612
1613<p>
1614Inline assembler expressions may <b>only</b> be used as the callee operand of
1615a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1616</p>
1617
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1618<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1619<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1620%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1621</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1622</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1623
1624<p>
1625Inline asms with side effects not visible in the constraint list must be marked
1626as having side effects. This is done through the use of the
1627'<tt>sideeffect</tt>' keyword, like so:
1628</p>
1629
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1630<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1631<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1632call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1633</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1634</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1635
1636<p>TODO: The format of the asm and constraints string still need to be
1637documented here. Constraints on what can be done (e.g. duplication, moving, etc
1638need to be documented).
1639</p>
1640
1641</div>
1642
1643<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1644<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1645<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1646
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1647<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1648
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1649<p>The LLVM instruction set consists of several different
1650classifications of instructions: <a href="#terminators">terminator
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1651instructions</a>, <a href="#binaryops">binary instructions</a>,
1652<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1653 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1654instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1655
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1656</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1657
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1658<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1659<div class="doc_subsection"> <a name="terminators">Terminator
1660Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1661
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1662<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1663
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1664<p>As mentioned <a href="#functionstructure">previously</a>, every
1665basic block in a program ends with a "Terminator" instruction, which
1666indicates which block should be executed after the current block is
1667finished. These terminator instructions typically yield a '<tt>void</tt>'
1668value: they produce control flow, not values (the one exception being
1669the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1670<p>There are six different terminator instructions: the '<a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1671 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1672instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1673the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1674 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1675 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1676
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1677</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1678
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1679<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1680<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1681Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1682<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1683<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1684<pre> ret &lt;type&gt; &lt;value&gt; <i>; Return a value from a non-void function</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1685 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1686</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1687<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1688<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1689value) from a function back to the caller.</p>
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]1690<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1691returns a value and then causes control flow, and one that just causes
1692control flow to occur.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1693<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1694<p>The '<tt>ret</tt>' instruction may return any '<a
1695 href="#t_firstclass">first class</a>' type. Notice that a function is
1696not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
1697instruction inside of the function that returns a value that does not
1698match the return type of the function.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1699<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1700<p>When the '<tt>ret</tt>' instruction is executed, control flow
1701returns back to the calling function's context. If the caller is a "<a
John Criswellfa081872004-06-25 15:16:57 +0000[diff] [blame]1702 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1703the instruction after the call. If the caller was an "<a
1704 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1705at the beginning of the "normal" destination block. If the instruction
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1706returns a value, that value shall set the call or invoke instruction's
1707return value.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1708<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1709<pre> ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1710 ret void <i>; Return from a void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1711</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1712</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1713<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1714<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1715<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1716<h5>Syntax:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1717<pre> br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1718</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1719<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1720<p>The '<tt>br</tt>' instruction is used to cause control flow to
1721transfer to a different basic block in the current function. There are
1722two forms of this instruction, corresponding to a conditional branch
1723and an unconditional branch.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1724<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1725<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1726single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1727unconditional form of the '<tt>br</tt>' instruction takes a single
1728'<tt>label</tt>' value as a target.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1729<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1730<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1731argument is evaluated. If the value is <tt>true</tt>, control flows
1732to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1733control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1734<h5>Example:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1735<pre>Test:<br> %cond = <a href="#i_icmp">icmp</a> eq, i32 %a, %b<br> br i1 %cond, label %IfEqual, label %IfUnequal<br>IfEqual:<br> <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1736 href="#i_ret">ret</a> i32 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> i32 0<br></pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1737</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1738<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1739<div class="doc_subsubsection">
1740 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1741</div>
1742
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1743<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1744<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1745
1746<pre>
1747 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1748</pre>
1749
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1750<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1751
1752<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1753several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1754instruction, allowing a branch to occur to one of many possible
1755destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1756
1757
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1758<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1759
1760<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1761comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1762an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1763table is not allowed to contain duplicate constant entries.</p>
1764
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1765<h5>Semantics:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1766
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1767<p>The <tt>switch</tt> instruction specifies a table of values and
1768destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1769table is searched for the given value. If the value is found, control flow is
1770transfered to the corresponding destination; otherwise, control flow is
1771transfered to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1772
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1773<h5>Implementation:</h5>
1774
1775<p>Depending on properties of the target machine and the particular
1776<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1777ways. For example, it could be generated as a series of chained conditional
1778branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1779
1780<h5>Example:</h5>
1781
1782<pre>
1783 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1784 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1785 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1786
1787 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1788 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1789
1790 <i>; Implement a jump table:</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1791 switch i32 %val, label %otherwise [ i32 0, label %onzero
1792 i32 1, label %onone
1793 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1794</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1795</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1796
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1797<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1798<div class="doc_subsubsection">
1799 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1800</div>
1801
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1802<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1803
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1804<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1805
1806<pre>
1807 &lt;result&gt; = invoke [<a href="#callingconv">cconv</a>] &lt;ptr to function ty&gt; %&lt;function ptr val&gt;(&lt;function args&gt;)
Chris Lattner76b8a332006-05-14 18:23:06 +0000[diff] [blame]1808 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1809</pre>
1810
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1811<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1812
1813<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1814function, with the possibility of control flow transfer to either the
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1815'<tt>normal</tt>' label or the
1816'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1817"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1818"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1819href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
1820continued at the dynamically nearest "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1821
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1822<h5>Arguments:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1823
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1824<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1825
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1826<ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1827 <li>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]1828 The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1829 convention</a> the call should use. If none is specified, the call defaults
1830 to using C calling conventions.
1831 </li>
1832 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1833 function value being invoked. In most cases, this is a direct function
1834 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1835 an arbitrary pointer to function value.
1836 </li>
1837
1838 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1839 function to be invoked. </li>
1840
1841 <li>'<tt>function args</tt>': argument list whose types match the function
1842 signature argument types. If the function signature indicates the function
1843 accepts a variable number of arguments, the extra arguments can be
1844 specified. </li>
1845
1846 <li>'<tt>normal label</tt>': the label reached when the called function
1847 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1848
1849 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1850 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1851
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1852</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1853
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1854<h5>Semantics:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1855
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1856<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1857href="#i_call">call</a></tt>' instruction in most regards. The primary
1858difference is that it establishes an association with a label, which is used by
1859the runtime library to unwind the stack.</p>
1860
1861<p>This instruction is used in languages with destructors to ensure that proper
1862cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1863exception. Additionally, this is important for implementation of
1864'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1865
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1866<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1867<pre>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1868 %retval = invoke i32 %Test(i32 15) to label %Continue
1869 unwind label %TestCleanup <i>; {i32}:retval set</i>
1870 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Test(i32 15) to label %Continue
1871 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1872</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1873</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1874
1875
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1876<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1877
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1878<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1879Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1880
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1881<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1882
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1883<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1884<pre>
1885 unwind
1886</pre>
1887
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1888<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1889
1890<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
1891at the first callee in the dynamic call stack which used an <a
1892href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
1893primarily used to implement exception handling.</p>
1894
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1895<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1896
1897<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
1898immediately halt. The dynamic call stack is then searched for the first <a
1899href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
1900execution continues at the "exceptional" destination block specified by the
1901<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
1902dynamic call chain, undefined behavior results.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1903</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1904
1905<!-- _______________________________________________________________________ -->
1906
1907<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
1908Instruction</a> </div>
1909
1910<div class="doc_text">
1911
1912<h5>Syntax:</h5>
1913<pre>
1914 unreachable
1915</pre>
1916
1917<h5>Overview:</h5>
1918
1919<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
1920instruction is used to inform the optimizer that a particular portion of the
1921code is not reachable. This can be used to indicate that the code after a
1922no-return function cannot be reached, and other facts.</p>
1923
1924<h5>Semantics:</h5>
1925
1926<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
1927</div>
1928
1929
1930
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1931<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1932<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1933<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1934<p>Binary operators are used to do most of the computation in a
1935program. They require two operands, execute an operation on them, and
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1936produce a single value. The operands might represent
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1937multiple data, as is the case with the <a href="#t_vector">vector</a> data type.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1938The result value of a binary operator is not
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1939necessarily the same type as its operands.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1940<p>There are several different binary operators:</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1941</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1942<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1943<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
1944Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1945<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1946<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1947<pre> &lt;result&gt; = add &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1948</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1949<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1950<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1951<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1952<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1953 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1954 This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1955Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1956<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1957<p>The value produced is the integer or floating point sum of the two
1958operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1959<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1960<pre> &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1961</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1962</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1963<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1964<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
1965Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1966<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1967<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1968<pre> &lt;result&gt; = sub &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1969</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1970<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1971<p>The '<tt>sub</tt>' instruction returns the difference of its two
1972operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1973<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
1974instruction present in most other intermediate representations.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1975<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1976<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1977 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1978values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1979This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1980Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1981<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1982<p>The value produced is the integer or floating point difference of
1983the two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1984<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]1985<pre>
1986 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1987 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1988</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1989</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1990<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1991<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
1992Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1993<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1994<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1995<pre> &lt;result&gt; = mul &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1996</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1997<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1998<p>The '<tt>mul</tt>' instruction returns the product of its two
1999operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2000<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2001<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2002 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2003values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2004This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2005Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2006<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2007<p>The value produced is the integer or floating point product of the
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2008two operands.</p>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]2009<p>Because the operands are the same width, the result of an integer
2010multiplication is the same whether the operands should be deemed unsigned or
2011signed.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2012<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2013<pre> &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2014</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2015</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2016<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2017<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2018</a></div>
2019<div class="doc_text">
2020<h5>Syntax:</h5>
2021<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2022</pre>
2023<h5>Overview:</h5>
2024<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2025operands.</p>
2026<h5>Arguments:</h5>
2027<p>The two arguments to the '<tt>udiv</tt>' instruction must be
2028<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2029types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2030of the values in which case the elements must be integers.</p>
2031<h5>Semantics:</h5>
2032<p>The value produced is the unsigned integer quotient of the two operands. This
2033instruction always performs an unsigned division operation, regardless of
2034whether the arguments are unsigned or not.</p>
2035<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2036<pre> &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2037</pre>
2038</div>
2039<!-- _______________________________________________________________________ -->
2040<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2041</a> </div>
2042<div class="doc_text">
2043<h5>Syntax:</h5>
2044<pre> &lt;result&gt; = sdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2045</pre>
2046<h5>Overview:</h5>
2047<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2048operands.</p>
2049<h5>Arguments:</h5>
2050<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2051<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2052types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2053of the values in which case the elements must be integers.</p>
2054<h5>Semantics:</h5>
2055<p>The value produced is the signed integer quotient of the two operands. This
2056instruction always performs a signed division operation, regardless of whether
2057the arguments are signed or not.</p>
2058<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2059<pre> &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2060</pre>
2061</div>
2062<!-- _______________________________________________________________________ -->
2063<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2064Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2065<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2066<h5>Syntax:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2067<pre> &lt;result&gt; = fdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2068</pre>
2069<h5>Overview:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2070<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2071operands.</p>
2072<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2073<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2074<a href="#t_floating">floating point</a> values. Both arguments must have
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2075identical types. This instruction can also take <a href="#t_vector">vector</a>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2076versions of floating point values.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2077<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2078<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2079<h5>Example:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2080<pre> &lt;result&gt; = fdiv float 4.0, %var <i>; yields {float}:result = 4.0 / %var</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2081</pre>
2082</div>
2083<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2084<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2085</div>
2086<div class="doc_text">
2087<h5>Syntax:</h5>
2088<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2089</pre>
2090<h5>Overview:</h5>
2091<p>The '<tt>urem</tt>' instruction returns the remainder from the
2092unsigned division of its two arguments.</p>
2093<h5>Arguments:</h5>
2094<p>The two arguments to the '<tt>urem</tt>' instruction must be
2095<a href="#t_integer">integer</a> values. Both arguments must have identical
2096types.</p>
2097<h5>Semantics:</h5>
2098<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
2099This instruction always performs an unsigned division to get the remainder,
2100regardless of whether the arguments are unsigned or not.</p>
2101<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2102<pre> &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2103</pre>
2104
2105</div>
2106<!-- _______________________________________________________________________ -->
2107<div class="doc_subsubsection"> <a name="i_srem">'<tt>srem</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2108Instruction</a> </div>
2109<div class="doc_text">
2110<h5>Syntax:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2111<pre> &lt;result&gt; = srem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2112</pre>
2113<h5>Overview:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2114<p>The '<tt>srem</tt>' instruction returns the remainder from the
2115signed division of its two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2116<h5>Arguments:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2117<p>The two arguments to the '<tt>srem</tt>' instruction must be
2118<a href="#t_integer">integer</a> values. Both arguments must have identical
2119types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2120<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2121<p>This instruction returns the <i>remainder</i> of a division (where the result
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2122has the same sign as the dividend, <tt>var1</tt>), not the <i>modulo</i>
2123operator (where the result has the same sign as the divisor, <tt>var2</tt>) of
2124a value. For more information about the difference, see <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2125 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2126Math Forum</a>. For a table of how this is implemented in various languages,
Reid Spencer64f5c6c2007-03-24 22:40:44 +0000[diff] [blame]2127please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2128Wikipedia: modulo operation</a>.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2129<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2130<pre> &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2131</pre>
2132
2133</div>
2134<!-- _______________________________________________________________________ -->
2135<div class="doc_subsubsection"> <a name="i_frem">'<tt>frem</tt>'
2136Instruction</a> </div>
2137<div class="doc_text">
2138<h5>Syntax:</h5>
2139<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2140</pre>
2141<h5>Overview:</h5>
2142<p>The '<tt>frem</tt>' instruction returns the remainder from the
2143division of its two operands.</p>
2144<h5>Arguments:</h5>
2145<p>The two arguments to the '<tt>frem</tt>' instruction must be
2146<a href="#t_floating">floating point</a> values. Both arguments must have
2147identical types.</p>
2148<h5>Semantics:</h5>
2149<p>This instruction returns the <i>remainder</i> of a division.</p>
2150<h5>Example:</h5>
2151<pre> &lt;result&gt; = frem float 4.0, %var <i>; yields {float}:result = 4.0 % %var</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2152</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2153</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]2154
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]2155<!-- ======================================================================= -->
2156<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2157Operations</a> </div>
2158<div class="doc_text">
2159<p>Bitwise binary operators are used to do various forms of
2160bit-twiddling in a program. They are generally very efficient
2161instructions and can commonly be strength reduced from other
2162instructions. They require two operands, execute an operation on them,
2163and produce a single value. The resulting value of the bitwise binary
2164operators is always the same type as its first operand.</p>
2165</div>
2166
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2167<!-- _______________________________________________________________________ -->
2168<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2169Instruction</a> </div>
2170<div class="doc_text">
2171<h5>Syntax:</h5>
2172<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2173</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2174
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2175<h5>Overview:</h5>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2176
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2177<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2178the left a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2179
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2180<h5>Arguments:</h5>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2181
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2182<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
2183 href="#t_integer">integer</a> type.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2184
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2185<h5>Semantics:</h5>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2186
2187<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>. If
2188<tt>var2</tt> is (statically or dynamically) equal to or larger than the number
2189of bits in <tt>var1</tt>, the result is undefined.</p>
2190
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2191<h5>Example:</h5><pre>
2192 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2193 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2194 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2195 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2196</pre>
2197</div>
2198<!-- _______________________________________________________________________ -->
2199<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2200Instruction</a> </div>
2201<div class="doc_text">
2202<h5>Syntax:</h5>
2203<pre> &lt;result&gt; = lshr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2204</pre>
2205
2206<h5>Overview:</h5>
2207<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2208operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2209
2210<h5>Arguments:</h5>
2211<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
2212<a href="#t_integer">integer</a> type.</p>
2213
2214<h5>Semantics:</h5>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2215
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2216<p>This instruction always performs a logical shift right operation. The most
2217significant bits of the result will be filled with zero bits after the
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2218shift. If <tt>var2</tt> is (statically or dynamically) equal to or larger than
2219the number of bits in <tt>var1</tt>, the result is undefined.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2220
2221<h5>Example:</h5>
2222<pre>
2223 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2224 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2225 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2226 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2227 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2228</pre>
2229</div>
2230
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]2231<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2232<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2233Instruction</a> </div>
2234<div class="doc_text">
2235
2236<h5>Syntax:</h5>
2237<pre> &lt;result&gt; = ashr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2238</pre>
2239
2240<h5>Overview:</h5>
2241<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2242operand shifted to the right a specified number of bits with sign extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2243
2244<h5>Arguments:</h5>
2245<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
2246<a href="#t_integer">integer</a> type.</p>
2247
2248<h5>Semantics:</h5>
2249<p>This instruction always performs an arithmetic shift right operation,
2250The most significant bits of the result will be filled with the sign bit
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2251of <tt>var1</tt>. If <tt>var2</tt> is (statically or dynamically) equal to or
2252larger than the number of bits in <tt>var1</tt>, the result is undefined.
2253</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2254
2255<h5>Example:</h5>
2256<pre>
2257 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2258 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2259 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2260 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2261 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2262</pre>
2263</div>
2264
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2265<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2266<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2267Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2268<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2269<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2270<pre> &lt;result&gt; = and &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2271</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2272<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2273<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2274its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2275<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2276<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2277 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2278identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2279<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2280<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2281<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2282<div style="align: center">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2283<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2284 <tbody>
2285 <tr>
2286 <td>In0</td>
2287 <td>In1</td>
2288 <td>Out</td>
2289 </tr>
2290 <tr>
2291 <td>0</td>
2292 <td>0</td>
2293 <td>0</td>
2294 </tr>
2295 <tr>
2296 <td>0</td>
2297 <td>1</td>
2298 <td>0</td>
2299 </tr>
2300 <tr>
2301 <td>1</td>
2302 <td>0</td>
2303 <td>0</td>
2304 </tr>
2305 <tr>
2306 <td>1</td>
2307 <td>1</td>
2308 <td>1</td>
2309 </tr>
2310 </tbody>
2311</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2312</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2313<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2314<pre> &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
2315 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2316 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2317</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2318</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2319<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2320<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2321<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2322<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2323<pre> &lt;result&gt; = or &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2324</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2325<h5>Overview:</h5>
2326<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2327or of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2328<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2329<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2330 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2331identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2332<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2333<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2334<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2335<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2336<table border="1" cellspacing="0" cellpadding="4">
2337 <tbody>
2338 <tr>
2339 <td>In0</td>
2340 <td>In1</td>
2341 <td>Out</td>
2342 </tr>
2343 <tr>
2344 <td>0</td>
2345 <td>0</td>
2346 <td>0</td>
2347 </tr>
2348 <tr>
2349 <td>0</td>
2350 <td>1</td>
2351 <td>1</td>
2352 </tr>
2353 <tr>
2354 <td>1</td>
2355 <td>0</td>
2356 <td>1</td>
2357 </tr>
2358 <tr>
2359 <td>1</td>
2360 <td>1</td>
2361 <td>1</td>
2362 </tr>
2363 </tbody>
2364</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2365</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2366<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2367<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2368 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2369 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2370</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2371</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2372<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2373<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2374Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2375<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2376<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2377<pre> &lt;result&gt; = xor &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2378</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2379<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2380<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2381or of its two operands. The <tt>xor</tt> is used to implement the
2382"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2383<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2384<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2385 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2386identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2387<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2388<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2389<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2390<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2391<table border="1" cellspacing="0" cellpadding="4">
2392 <tbody>
2393 <tr>
2394 <td>In0</td>
2395 <td>In1</td>
2396 <td>Out</td>
2397 </tr>
2398 <tr>
2399 <td>0</td>
2400 <td>0</td>
2401 <td>0</td>
2402 </tr>
2403 <tr>
2404 <td>0</td>
2405 <td>1</td>
2406 <td>1</td>
2407 </tr>
2408 <tr>
2409 <td>1</td>
2410 <td>0</td>
2411 <td>1</td>
2412 </tr>
2413 <tr>
2414 <td>1</td>
2415 <td>1</td>
2416 <td>0</td>
2417 </tr>
2418 </tbody>
2419</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2420</div>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2421<p> </p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2422<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2423<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2424 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2425 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2426 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2427</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2428</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2429
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2430<!-- ======================================================================= -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2431<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2432 <a name="vectorops">Vector Operations</a>
2433</div>
2434
2435<div class="doc_text">
2436
2437<p>LLVM supports several instructions to represent vector operations in a
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2438target-independent manner. These instructions cover the element-access and
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2439vector-specific operations needed to process vectors effectively. While LLVM
2440does directly support these vector operations, many sophisticated algorithms
2441will want to use target-specific intrinsics to take full advantage of a specific
2442target.</p>
2443
2444</div>
2445
2446<!-- _______________________________________________________________________ -->
2447<div class="doc_subsubsection">
2448 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2449</div>
2450
2451<div class="doc_text">
2452
2453<h5>Syntax:</h5>
2454
2455<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2456 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2457</pre>
2458
2459<h5>Overview:</h5>
2460
2461<p>
2462The '<tt>extractelement</tt>' instruction extracts a single scalar
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2463element from a vector at a specified index.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2464</p>
2465
2466
2467<h5>Arguments:</h5>
2468
2469<p>
2470The first operand of an '<tt>extractelement</tt>' instruction is a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2471value of <a href="#t_vector">vector</a> type. The second operand is
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2472an index indicating the position from which to extract the element.
2473The index may be a variable.</p>
2474
2475<h5>Semantics:</h5>
2476
2477<p>
2478The result is a scalar of the same type as the element type of
2479<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2480<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2481results are undefined.
2482</p>
2483
2484<h5>Example:</h5>
2485
2486<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2487 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2488</pre>
2489</div>
2490
2491
2492<!-- _______________________________________________________________________ -->
2493<div class="doc_subsubsection">
2494 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2495</div>
2496
2497<div class="doc_text">
2498
2499<h5>Syntax:</h5>
2500
2501<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2502 &lt;result&gt; = insertelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, &lt;ty&gt; &lt;elt&gt, i32 &lt;idx&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2503</pre>
2504
2505<h5>Overview:</h5>
2506
2507<p>
2508The '<tt>insertelement</tt>' instruction inserts a scalar
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2509element into a vector at a specified index.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2510</p>
2511
2512
2513<h5>Arguments:</h5>
2514
2515<p>
2516The first operand of an '<tt>insertelement</tt>' instruction is a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2517value of <a href="#t_vector">vector</a> type. The second operand is a
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2518scalar value whose type must equal the element type of the first
2519operand. The third operand is an index indicating the position at
2520which to insert the value. The index may be a variable.</p>
2521
2522<h5>Semantics:</h5>
2523
2524<p>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2525The result is a vector of the same type as <tt>val</tt>. Its
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2526element values are those of <tt>val</tt> except at position
2527<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2528exceeds the length of <tt>val</tt>, the results are undefined.
2529</p>
2530
2531<h5>Example:</h5>
2532
2533<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2534 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2535</pre>
2536</div>
2537
2538<!-- _______________________________________________________________________ -->
2539<div class="doc_subsubsection">
2540 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2541</div>
2542
2543<div class="doc_text">
2544
2545<h5>Syntax:</h5>
2546
2547<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2548 &lt;result&gt; = shufflevector &lt;n x &lt;ty&gt;&gt; &lt;v1&gt;, &lt;n x &lt;ty&gt;&gt; &lt;v2&gt;, &lt;n x i32&gt; &lt;mask&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2549</pre>
2550
2551<h5>Overview:</h5>
2552
2553<p>
2554The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2555from two input vectors, returning a vector of the same type.
2556</p>
2557
2558<h5>Arguments:</h5>
2559
2560<p>
2561The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2562with types that match each other and types that match the result of the
2563instruction. The third argument is a shuffle mask, which has the same number
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2564of elements as the other vector type, but whose element type is always 'i32'.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2565</p>
2566
2567<p>
2568The shuffle mask operand is required to be a constant vector with either
2569constant integer or undef values.
2570</p>
2571
2572<h5>Semantics:</h5>
2573
2574<p>
2575The elements of the two input vectors are numbered from left to right across
2576both of the vectors. The shuffle mask operand specifies, for each element of
2577the result vector, which element of the two input registers the result element
2578gets. The element selector may be undef (meaning "don't care") and the second
2579operand may be undef if performing a shuffle from only one vector.
2580</p>
2581
2582<h5>Example:</h5>
2583
2584<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2585 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2586 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2587 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2588 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i> - Identity shuffle.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2589</pre>
2590</div>
2591
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]2592
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2593<!-- ======================================================================= -->
2594<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2595 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2596</div>
2597
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2598<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2599
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2600<p>A key design point of an SSA-based representation is how it
2601represents memory. In LLVM, no memory locations are in SSA form, which
2602makes things very simple. This section describes how to read, write,
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2603allocate, and free memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2604
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2605</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2606
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2607<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2608<div class="doc_subsubsection">
2609 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2610</div>
2611
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2612<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2613
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2614<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2615
2616<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2617 &lt;result&gt; = malloc &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2618</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2619
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2620<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2621
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2622<p>The '<tt>malloc</tt>' instruction allocates memory from the system
2623heap and returns a pointer to it.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2624
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2625<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2626
2627<p>The '<tt>malloc</tt>' instruction allocates
2628<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswell6e4ca612004-02-24 16:13:56 +0000[diff] [blame]2629bytes of memory from the operating system and returns a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2630appropriate type to the program. If "NumElements" is specified, it is the
2631number of elements allocated. If an alignment is specified, the value result
2632of the allocation is guaranteed to be aligned to at least that boundary. If
2633not specified, or if zero, the target can choose to align the allocation on any
2634convenient boundary.</p>
2635
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2636<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2637
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2638<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2639
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2640<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
2641a pointer is returned.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2642
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2643<h5>Example:</h5>
2644
2645<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2646 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2647
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]2648 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
2649 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
2650 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
2651 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
2652 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2653</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2654</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2655
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2656<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2657<div class="doc_subsubsection">
2658 <a name="i_free">'<tt>free</tt>' Instruction</a>
2659</div>
2660
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2661<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2662
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2663<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2664
2665<pre>
2666 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2667</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2668
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2669<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2670
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2671<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2672memory heap to be reallocated in the future.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2673
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2674<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2675
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2676<p>'<tt>value</tt>' shall be a pointer value that points to a value
2677that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
2678instruction.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2679
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2680<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2681
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2682<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2683after this instruction executes.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2684
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2685<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2686
2687<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2688 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
2689 free [4 x i8]* %array
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2690</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2691</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2692
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2693<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2694<div class="doc_subsubsection">
2695 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
2696</div>
2697
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2698<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2699
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2700<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2701
2702<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2703 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2704</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2705
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2706<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2707
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2708<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
2709currently executing function, to be automatically released when this function
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2710returns to its caller.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2711
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2712<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2713
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2714<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2715bytes of memory on the runtime stack, returning a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2716appropriate type to the program. If "NumElements" is specified, it is the
2717number of elements allocated. If an alignment is specified, the value result
2718of the allocation is guaranteed to be aligned to at least that boundary. If
2719not specified, or if zero, the target can choose to align the allocation on any
2720convenient boundary.</p>
2721
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2722<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2723
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2724<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2725
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2726<p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2727memory is automatically released when the function returns. The '<tt>alloca</tt>'
2728instruction is commonly used to represent automatic variables that must
2729have an address available. When the function returns (either with the <tt><a
John Criswelldae2e932005-05-12 16:55:34 +0000[diff] [blame]2730 href="#i_ret">ret</a></tt> or <tt><a href="#i_unwind">unwind</a></tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2731instructions), the memory is reclaimed.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2732
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2733<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2734
2735<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2736 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2737 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
2738 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2739 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2740</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2741</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2742
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2743<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2744<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
2745Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2746<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2747<h5>Syntax:</h5>
Christopher Lamb2330e4d2007-04-21 08:16:25 +0000[diff] [blame]2748<pre> &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]<br> &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]<br></pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2749<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2750<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2751<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2752<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2753address from which to load. The pointer must point to a <a
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]2754 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2755marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2756the number or order of execution of this <tt>load</tt> with other
2757volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
2758instructions. </p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2759<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2760<p>The location of memory pointed to is loaded.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2761<h5>Examples:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2762<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2763 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2764 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2765 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2766</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2767</div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2768<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2769<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
2770Instruction</a> </div>
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]2771<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2772<h5>Syntax:</h5>
Christopher Lamb2330e4d2007-04-21 08:16:25 +0000[diff] [blame]2773<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
2774 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2775</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2776<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2777<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2778<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2779<p>There are two arguments to the '<tt>store</tt>' instruction: a value
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2780to store and an address at which to store it. The type of the '<tt>&lt;pointer&gt;</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2781operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2782operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2783optimizer is not allowed to modify the number or order of execution of
2784this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
2785 href="#i_store">store</a></tt> instructions.</p>
2786<h5>Semantics:</h5>
2787<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
2788at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2789<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2790<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2791 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2792 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2793 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2794</pre>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2795</div>
2796
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2797<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2798<div class="doc_subsubsection">
2799 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
2800</div>
2801
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2802<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2803<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2804<pre>
2805 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
2806</pre>
2807
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2808<h5>Overview:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2809
2810<p>
2811The '<tt>getelementptr</tt>' instruction is used to get the address of a
2812subelement of an aggregate data structure.</p>
2813
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2814<h5>Arguments:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2815
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2816<p>This instruction takes a list of integer operands that indicate what
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2817elements of the aggregate object to index to. The actual types of the arguments
2818provided depend on the type of the first pointer argument. The
2819'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2820levels of a structure or to a specific index in an array. When indexing into a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2821structure, only <tt>i32</tt> integer constants are allowed. When indexing
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2822into an array or pointer, only integers of 32 or 64 bits are allowed, and will
2823be sign extended to 64-bit values.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2824
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2825<p>For example, let's consider a C code fragment and how it gets
2826compiled to LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2827
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2828<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2829<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2830struct RT {
2831 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]2832 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2833 char C;
2834};
2835struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]2836 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2837 double Y;
2838 struct RT Z;
2839};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2840
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]2841int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2842 return &amp;s[1].Z.B[5][13];
2843}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2844</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2845</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2846
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2847<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2848
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2849<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2850<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2851%RT = type { i8 , [10 x [20 x i32]], i8 }
2852%ST = type { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2853
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2854define i32* %foo(%ST* %s) {
2855entry:
2856 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
2857 ret i32* %reg
2858}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2859</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2860</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2861
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2862<h5>Semantics:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2863
2864<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2865on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2866and <a href="#t_array">array</a> types can use a 32-bit or 64-bit
Reid Spencer42ddd842006-12-03 16:53:48 +0000[diff] [blame]2867<a href="#t_integer">integer</a> type but the value will always be sign extended
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2868to 64-bits. <a href="#t_struct">Structure</a> types require <tt>i32</tt>
Reid Spencer42ddd842006-12-03 16:53:48 +0000[diff] [blame]2869<b>constants</b>.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2870
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2871<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2872type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2873}</tt>' type, a structure. The second index indexes into the third element of
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2874the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
2875i8 }</tt>' type, another structure. The third index indexes into the second
2876element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2877array. The two dimensions of the array are subscripted into, yielding an
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2878'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
2879to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2880
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2881<p>Note that it is perfectly legal to index partially through a
2882structure, returning a pointer to an inner element. Because of this,
2883the LLVM code for the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2884
2885<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2886 define i32* %foo(%ST* %s) {
2887 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2888 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
2889 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2890 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
2891 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
2892 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2893 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2894</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2895
2896<p>Note that it is undefined to access an array out of bounds: array and
2897pointer indexes must always be within the defined bounds of the array type.
2898The one exception for this rules is zero length arrays. These arrays are
2899defined to be accessible as variable length arrays, which requires access
2900beyond the zero'th element.</p>
2901
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2902<p>The getelementptr instruction is often confusing. For some more insight
2903into how it works, see <a href="GetElementPtr.html">the getelementptr
2904FAQ</a>.</p>
2905
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2906<h5>Example:</h5>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2907
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2908<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2909 <i>; yields [12 x i8]*:aptr</i>
2910 %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2911</pre>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2912</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2913
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2914<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]2915<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2916</div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2917<div class="doc_text">
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]2918<p>The instructions in this category are the conversion instructions (casting)
2919which all take a single operand and a type. They perform various bit conversions
2920on the operand.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2921</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2922
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2923<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2924<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2925 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
2926</div>
2927<div class="doc_text">
2928
2929<h5>Syntax:</h5>
2930<pre>
2931 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2932</pre>
2933
2934<h5>Overview:</h5>
2935<p>
2936The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
2937</p>
2938
2939<h5>Arguments:</h5>
2940<p>
2941The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
2942be an <a href="#t_integer">integer</a> type, and a type that specifies the size
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2943and type of the result, which must be an <a href="#t_integer">integer</a>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2944type. The bit size of <tt>value</tt> must be larger than the bit size of
2945<tt>ty2</tt>. Equal sized types are not allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2946
2947<h5>Semantics:</h5>
2948<p>
2949The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2950and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
2951larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
2952It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2953
2954<h5>Example:</h5>
2955<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2956 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2957 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
2958 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2959</pre>
2960</div>
2961
2962<!-- _______________________________________________________________________ -->
2963<div class="doc_subsubsection">
2964 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
2965</div>
2966<div class="doc_text">
2967
2968<h5>Syntax:</h5>
2969<pre>
2970 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2971</pre>
2972
2973<h5>Overview:</h5>
2974<p>The '<tt>zext</tt>' instruction zero extends its operand to type
2975<tt>ty2</tt>.</p>
2976
2977
2978<h5>Arguments:</h5>
2979<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2980<a href="#t_integer">integer</a> type, and a type to cast it to, which must
2981also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2982<tt>value</tt> must be smaller than the bit size of the destination type,
2983<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2984
2985<h5>Semantics:</h5>
2986<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
Chris Lattnerd1d25172007-05-24 19:13:27 +0000[diff] [blame]2987bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2988
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]2989<p>When zero extending from i1, the result will always be either 0 or 1.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2990
2991<h5>Example:</h5>
2992<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2993 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2994 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2995</pre>
2996</div>
2997
2998<!-- _______________________________________________________________________ -->
2999<div class="doc_subsubsection">
3000 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
3001</div>
3002<div class="doc_text">
3003
3004<h5>Syntax:</h5>
3005<pre>
3006 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3007</pre>
3008
3009<h5>Overview:</h5>
3010<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
3011
3012<h5>Arguments:</h5>
3013<p>
3014The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3015<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3016also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3017<tt>value</tt> must be smaller than the bit size of the destination type,
3018<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3019
3020<h5>Semantics:</h5>
3021<p>
3022The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3023bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
Chris Lattnerd1d25172007-05-24 19:13:27 +0000[diff] [blame]3024the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3025
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3026<p>When sign extending from i1, the extension always results in -1 or 0.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3027
3028<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3029<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3030 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3031 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3032</pre>
3033</div>
3034
3035<!-- _______________________________________________________________________ -->
3036<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]3037 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3038</div>
3039
3040<div class="doc_text">
3041
3042<h5>Syntax:</h5>
3043
3044<pre>
3045 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3046</pre>
3047
3048<h5>Overview:</h5>
3049<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3050<tt>ty2</tt>.</p>
3051
3052
3053<h5>Arguments:</h5>
3054<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
3055 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
3056cast it to. The size of <tt>value</tt> must be larger than the size of
3057<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
3058<i>no-op cast</i>.</p>
3059
3060<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3061<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
3062<a href="#t_floating">floating point</a> type to a smaller
3063<a href="#t_floating">floating point</a> type. If the value cannot fit within
3064the destination type, <tt>ty2</tt>, then the results are undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]3065
3066<h5>Example:</h5>
3067<pre>
3068 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
3069 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
3070</pre>
3071</div>
3072
3073<!-- _______________________________________________________________________ -->
3074<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3075 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3076</div>
3077<div class="doc_text">
3078
3079<h5>Syntax:</h5>
3080<pre>
3081 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3082</pre>
3083
3084<h5>Overview:</h5>
3085<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3086floating point value.</p>
3087
3088<h5>Arguments:</h5>
3089<p>The '<tt>fpext</tt>' instruction takes a
3090<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3091and a <a href="#t_floating">floating point</a> type to cast it to. The source
3092type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3093
3094<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3095<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3096<a href="#t_floating">floating point</a> type to a larger
3097<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3098used to make a <i>no-op cast</i> because it always changes bits. Use
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3099<tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3100
3101<h5>Example:</h5>
3102<pre>
3103 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3104 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3105</pre>
3106</div>
3107
3108<!-- _______________________________________________________________________ -->
3109<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]3110 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3111</div>
3112<div class="doc_text">
3113
3114<h5>Syntax:</h5>
3115<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3116 &lt;result&gt; = fptoui &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3117</pre>
3118
3119<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3120<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3121unsigned integer equivalent of type <tt>ty2</tt>.
3122</p>
3123
3124<h5>Arguments:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3125<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3126<a href="#t_floating">floating point</a> value, and a type to cast it to, which
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3127must be an <a href="#t_integer">integer</a> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3128
3129<h5>Semantics:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3130<p> The '<tt>fptoui</tt>' instruction converts its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3131<a href="#t_floating">floating point</a> operand into the nearest (rounding
3132towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3133the results are undefined.</p>
3134
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3135<h5>Example:</h5>
3136<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3137 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]3138 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3139 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3140</pre>
3141</div>
3142
3143<!-- _______________________________________________________________________ -->
3144<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3145 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3146</div>
3147<div class="doc_text">
3148
3149<h5>Syntax:</h5>
3150<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3151 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3152</pre>
3153
3154<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3155<p>The '<tt>fptosi</tt>' instruction converts
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3156<a href="#t_floating">floating point</a> <tt>value</tt> to type <tt>ty2</tt>.
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3157</p>
3158
3159
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3160<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3161<p> The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3162<a href="#t_floating">floating point</a> value, and a type to cast it to, which
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3163must also be an <a href="#t_integer">integer</a> type.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3164
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3165<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3166<p>The '<tt>fptosi</tt>' instruction converts its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3167<a href="#t_floating">floating point</a> operand into the nearest (rounding
3168towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3169the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3170
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3171<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3172<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3173 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]3174 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3175 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3176</pre>
3177</div>
3178
3179<!-- _______________________________________________________________________ -->
3180<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3181 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3182</div>
3183<div class="doc_text">
3184
3185<h5>Syntax:</h5>
3186<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3187 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3188</pre>
3189
3190<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3191<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3192integer and converts that value to the <tt>ty2</tt> type.</p>
3193
3194
3195<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3196<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be an
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3197<a href="#t_integer">integer</a> value, and a type to cast it to, which must
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3198be a <a href="#t_floating">floating point</a> type.</p>
3199
3200<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3201<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3202integer quantity and converts it to the corresponding floating point value. If
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]3203the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3204
3205
3206<h5>Example:</h5>
3207<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3208 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3209 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3210</pre>
3211</div>
3212
3213<!-- _______________________________________________________________________ -->
3214<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3215 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3216</div>
3217<div class="doc_text">
3218
3219<h5>Syntax:</h5>
3220<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3221 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3222</pre>
3223
3224<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3225<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3226integer and converts that value to the <tt>ty2</tt> type.</p>
3227
3228<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3229<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be an
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3230<a href="#t_integer">integer</a> value, and a type to cast it to, which must be
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3231a <a href="#t_floating">floating point</a> type.</p>
3232
3233<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3234<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3235integer quantity and converts it to the corresponding floating point value. If
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]3236the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3237
3238<h5>Example:</h5>
3239<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3240 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3241 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3242</pre>
3243</div>
3244
3245<!-- _______________________________________________________________________ -->
3246<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3247 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3248</div>
3249<div class="doc_text">
3250
3251<h5>Syntax:</h5>
3252<pre>
3253 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3254</pre>
3255
3256<h5>Overview:</h5>
3257<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3258the integer type <tt>ty2</tt>.</p>
3259
3260<h5>Arguments:</h5>
3261<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3262must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3263<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
3264
3265<h5>Semantics:</h5>
3266<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3267<tt>ty2</tt> by interpreting the pointer value as an integer and either
3268truncating or zero extending that value to the size of the integer type. If
3269<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3270<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3271are the same size, then nothing is done (<i>no-op cast</i>) other than a type
3272change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3273
3274<h5>Example:</h5>
3275<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3276 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
3277 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3278</pre>
3279</div>
3280
3281<!-- _______________________________________________________________________ -->
3282<div class="doc_subsubsection">
3283 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3284</div>
3285<div class="doc_text">
3286
3287<h5>Syntax:</h5>
3288<pre>
3289 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3290</pre>
3291
3292<h5>Overview:</h5>
3293<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3294a pointer type, <tt>ty2</tt>.</p>
3295
3296<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3297<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3298value to cast, and a type to cast it to, which must be a
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]3299<a href="#t_pointer">pointer</a> type.
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3300
3301<h5>Semantics:</h5>
3302<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3303<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3304the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3305size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3306the size of a pointer then a zero extension is done. If they are the same size,
3307nothing is done (<i>no-op cast</i>).</p>
3308
3309<h5>Example:</h5>
3310<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3311 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
3312 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
3313 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3314</pre>
3315</div>
3316
3317<!-- _______________________________________________________________________ -->
3318<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3319 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3320</div>
3321<div class="doc_text">
3322
3323<h5>Syntax:</h5>
3324<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3325 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3326</pre>
3327
3328<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3329<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3330<tt>ty2</tt> without changing any bits.</p>
3331
3332<h5>Arguments:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3333<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3334a first class value, and a type to cast it to, which must also be a <a
3335 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
Reid Spencer19b569f2007-01-09 20:08:58 +0000[diff] [blame]3336and the destination type, <tt>ty2</tt>, must be identical. If the source
3337type is a pointer, the destination type must also be a pointer.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3338
3339<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3340<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3341<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3342this conversion. The conversion is done as if the <tt>value</tt> had been
3343stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3344converted to other pointer types with this instruction. To convert pointers to
3345other types, use the <a href="#i_inttoptr">inttoptr</a> or
3346<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3347
3348<h5>Example:</h5>
3349<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3350 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3351 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
3352 %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3353</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3354</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3355
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3356<!-- ======================================================================= -->
3357<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3358<div class="doc_text">
3359<p>The instructions in this category are the "miscellaneous"
3360instructions, which defy better classification.</p>
3361</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3362
3363<!-- _______________________________________________________________________ -->
3364<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3365</div>
3366<div class="doc_text">
3367<h5>Syntax:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3368<pre> &lt;result&gt; = icmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {i1}:result</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3369</pre>
3370<h5>Overview:</h5>
3371<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
3372of its two integer operands.</p>
3373<h5>Arguments:</h5>
3374<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3375the condition code indicating the kind of comparison to perform. It is not
3376a value, just a keyword. The possible condition code are:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3377<ol>
3378 <li><tt>eq</tt>: equal</li>
3379 <li><tt>ne</tt>: not equal </li>
3380 <li><tt>ugt</tt>: unsigned greater than</li>
3381 <li><tt>uge</tt>: unsigned greater or equal</li>
3382 <li><tt>ult</tt>: unsigned less than</li>
3383 <li><tt>ule</tt>: unsigned less or equal</li>
3384 <li><tt>sgt</tt>: signed greater than</li>
3385 <li><tt>sge</tt>: signed greater or equal</li>
3386 <li><tt>slt</tt>: signed less than</li>
3387 <li><tt>sle</tt>: signed less or equal</li>
3388</ol>
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3389<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3390<a href="#t_pointer">pointer</a> typed. They must also be identical types.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3391<h5>Semantics:</h5>
3392<p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3393the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3394yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3395<ol>
3396 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3397 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3398 </li>
3399 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3400 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3401 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3402 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3403 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3404 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3405 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3406 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3407 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3408 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3409 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3410 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3411 <li><tt>sge</tt>: interprets the operands as signed values and yields
3412 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3413 <li><tt>slt</tt>: interprets the operands as signed values and yields
3414 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3415 <li><tt>sle</tt>: interprets the operands as signed values and yields
3416 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3417</ol>
3418<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3419values are compared as if they were integers.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3420
3421<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3422<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3423 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3424 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3425 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3426 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3427 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3428</pre>
3429</div>
3430
3431<!-- _______________________________________________________________________ -->
3432<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3433</div>
3434<div class="doc_text">
3435<h5>Syntax:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3436<pre> &lt;result&gt; = fcmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {i1}:result</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3437</pre>
3438<h5>Overview:</h5>
3439<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3440of its floating point operands.</p>
3441<h5>Arguments:</h5>
3442<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3443the condition code indicating the kind of comparison to perform. It is not
3444a value, just a keyword. The possible condition code are:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3445<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3446 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3447 <li><tt>oeq</tt>: ordered and equal</li>
3448 <li><tt>ogt</tt>: ordered and greater than </li>
3449 <li><tt>oge</tt>: ordered and greater than or equal</li>
3450 <li><tt>olt</tt>: ordered and less than </li>
3451 <li><tt>ole</tt>: ordered and less than or equal</li>
3452 <li><tt>one</tt>: ordered and not equal</li>
3453 <li><tt>ord</tt>: ordered (no nans)</li>
3454 <li><tt>ueq</tt>: unordered or equal</li>
3455 <li><tt>ugt</tt>: unordered or greater than </li>
3456 <li><tt>uge</tt>: unordered or greater than or equal</li>
3457 <li><tt>ult</tt>: unordered or less than </li>
3458 <li><tt>ule</tt>: unordered or less than or equal</li>
3459 <li><tt>une</tt>: unordered or not equal</li>
3460 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3461 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3462</ol>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3463<p><i>Ordered</i> means that neither operand is a QNAN while
Reid Spencer93a49852006-12-06 07:08:07 +0000[diff] [blame]3464<i>unordered</i> means that either operand may be a QNAN.</p>
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3465<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be
3466<a href="#t_floating">floating point</a> typed. They must have identical
3467types.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3468<h5>Semantics:</h5>
3469<p>The '<tt>fcmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3470the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3471yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3472<ol>
3473 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3474 <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3475 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3476 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3477 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3478 <li><tt>oge</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3479 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3480 <li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3481 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3482 <li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3483 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3484 <li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3485 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3486 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3487 <li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3488 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3489 <li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3490 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3491 <li><tt>uge</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3492 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3493 <li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3494 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3495 <li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3496 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3497 <li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3498 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3499 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3500 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3501</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3502
3503<h5>Example:</h5>
3504<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3505 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3506 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3507 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3508</pre>
3509</div>
3510
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3511<!-- _______________________________________________________________________ -->
3512<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
3513Instruction</a> </div>
3514<div class="doc_text">
3515<h5>Syntax:</h5>
3516<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
3517<h5>Overview:</h5>
3518<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
3519the SSA graph representing the function.</p>
3520<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3521<p>The type of the incoming values is specified with the first type
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3522field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
3523as arguments, with one pair for each predecessor basic block of the
3524current block. Only values of <a href="#t_firstclass">first class</a>
3525type may be used as the value arguments to the PHI node. Only labels
3526may be used as the label arguments.</p>
3527<p>There must be no non-phi instructions between the start of a basic
3528block and the PHI instructions: i.e. PHI instructions must be first in
3529a basic block.</p>
3530<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3531<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
3532specified by the pair corresponding to the predecessor basic block that executed
3533just prior to the current block.</p>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3534<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3535<pre>Loop: ; Infinite loop that counts from 0 on up...<br> %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]<br> %nextindvar = add i32 %indvar, 1<br> br label %Loop<br></pre>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3536</div>
3537
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3538<!-- _______________________________________________________________________ -->
3539<div class="doc_subsubsection">
3540 <a name="i_select">'<tt>select</tt>' Instruction</a>
3541</div>
3542
3543<div class="doc_text">
3544
3545<h5>Syntax:</h5>
3546
3547<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3548 &lt;result&gt; = select i1 &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3549</pre>
3550
3551<h5>Overview:</h5>
3552
3553<p>
3554The '<tt>select</tt>' instruction is used to choose one value based on a
3555condition, without branching.
3556</p>
3557
3558
3559<h5>Arguments:</h5>
3560
3561<p>
3562The '<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.
3563</p>
3564
3565<h5>Semantics:</h5>
3566
3567<p>
3568If the boolean condition evaluates to true, the instruction returns the first
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3569value argument; otherwise, it returns the second value argument.
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3570</p>
3571
3572<h5>Example:</h5>
3573
3574<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3575 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3576</pre>
3577</div>
3578
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]3579
3580<!-- _______________________________________________________________________ -->
3581<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3582 <a name="i_call">'<tt>call</tt>' Instruction</a>
3583</div>
3584
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3585<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3586
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3587<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3588<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]3589 &lt;result&gt; = [tail] call [<a href="#callingconv">cconv</a>] &lt;ty&gt; [&lt;fnty&gt;*] &lt;fnptrval&gt;(&lt;param list&gt;)
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3590</pre>
3591
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3592<h5>Overview:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3593
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3594<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3595
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3596<h5>Arguments:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3597
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3598<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3599
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3600<ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3601 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3602 <p>The optional "tail" marker indicates whether the callee function accesses
3603 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3604 function call is eligible for tail call optimization. Note that calls may
3605 be marked "tail" even if they do not occur before a <a
3606 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3607 </li>
3608 <li>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3609 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3610 convention</a> the call should use. If none is specified, the call defaults
3611 to using C calling conventions.
3612 </li>
3613 <li>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]3614 <p>'<tt>ty</tt>': the type of the call instruction itself which is also
3615 the type of the return value. Functions that return no value are marked
3616 <tt><a href="#t_void">void</a></tt>.</p>
3617 </li>
3618 <li>
3619 <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
3620 value being invoked. The argument types must match the types implied by
3621 this signature. This type can be omitted if the function is not varargs
3622 and if the function type does not return a pointer to a function.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3623 </li>
3624 <li>
3625 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
3626 be invoked. In most cases, this is a direct function invocation, but
3627 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3628 to function value.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3629 </li>
3630 <li>
3631 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencera7e302a2005-05-01 22:22:57 +0000[diff] [blame]3632 function signature argument types. All arguments must be of
3633 <a href="#t_firstclass">first class</a> type. If the function signature
3634 indicates the function accepts a variable number of arguments, the extra
3635 arguments can be specified.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3636 </li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3637</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3638
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3639<h5>Semantics:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3640
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3641<p>The '<tt>call</tt>' instruction is used to cause control flow to
3642transfer to a specified function, with its incoming arguments bound to
3643the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
3644instruction in the called function, control flow continues with the
3645instruction after the function call, and the return value of the
3646function is bound to the result argument. This is a simpler case of
3647the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3648
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3649<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3650
3651<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]3652 %retval = call i32 @test(i32 %argc)
3653 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42);
3654 %X = tail call i32 @foo()
3655 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo()
3656 %Z = call void %foo(i8 97 signext)
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3657</pre>
3658
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3659</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3660
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3661<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3662<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3663 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3664</div>
3665
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3666<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3667
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3668<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3669
3670<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3671 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3672</pre>
3673
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3674<h5>Overview:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3675
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3676<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3677the "variable argument" area of a function call. It is used to implement the
3678<tt>va_arg</tt> macro in C.</p>
3679
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3680<h5>Arguments:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3681
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3682<p>This instruction takes a <tt>va_list*</tt> value and the type of
3683the argument. It returns a value of the specified argument type and
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3684increments the <tt>va_list</tt> to point to the next argument. The
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3685actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3686
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3687<h5>Semantics:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3688
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3689<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
3690type from the specified <tt>va_list</tt> and causes the
3691<tt>va_list</tt> to point to the next argument. For more information,
3692see the variable argument handling <a href="#int_varargs">Intrinsic
3693Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3694
3695<p>It is legal for this instruction to be called in a function which does not
3696take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3697function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3698
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3699<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3700href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3701argument.</p>
3702
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3703<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3704
3705<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
3706
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3707</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3708
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3709<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3710<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
3711<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3712
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3713<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3714
3715<p>LLVM supports the notion of an "intrinsic function". These functions have
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]3716well known names and semantics and are required to follow certain restrictions.
3717Overall, these intrinsics represent an extension mechanism for the LLVM
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3718language that does not require changing all of the transformations in LLVM when
Gabor Greif04367bf2007-07-06 22:07:22 +0000[diff] [blame]3719adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3720
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3721<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3722prefix is reserved in LLVM for intrinsic names; thus, function names may not
3723begin with this prefix. Intrinsic functions must always be external functions:
3724you cannot define the body of intrinsic functions. Intrinsic functions may
3725only be used in call or invoke instructions: it is illegal to take the address
3726of an intrinsic function. Additionally, because intrinsic functions are part
3727of the LLVM language, it is required if any are added that they be documented
3728here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3729
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]3730<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
3731a family of functions that perform the same operation but on different data
3732types. Because LLVM can represent over 8 million different integer types,
3733overloading is used commonly to allow an intrinsic function to operate on any
3734integer type. One or more of the argument types or the result type can be
3735overloaded to accept any integer type. Argument types may also be defined as
3736exactly matching a previous argument's type or the result type. This allows an
3737intrinsic function which accepts multiple arguments, but needs all of them to
3738be of the same type, to only be overloaded with respect to a single argument or
3739the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3740
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]3741<p>Overloaded intrinsics will have the names of its overloaded argument types
3742encoded into its function name, each preceded by a period. Only those types
3743which are overloaded result in a name suffix. Arguments whose type is matched
3744against another type do not. For example, the <tt>llvm.ctpop</tt> function can
3745take an integer of any width and returns an integer of exactly the same integer
3746width. This leads to a family of functions such as
3747<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
3748Only one type, the return type, is overloaded, and only one type suffix is
3749required. Because the argument's type is matched against the return type, it
3750does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]3751
3752<p>To learn how to add an intrinsic function, please see the
3753<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3754</p>
3755
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3756</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3757
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3758<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3759<div class="doc_subsection">
3760 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
3761</div>
3762
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3763<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3764
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3765<p>Variable argument support is defined in LLVM with the <a
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3766 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3767intrinsic functions. These functions are related to the similarly
3768named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3769
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3770<p>All of these functions operate on arguments that use a
3771target-specific value type "<tt>va_list</tt>". The LLVM assembly
3772language reference manual does not define what this type is, so all
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3773transformations should be prepared to handle these functions regardless of
3774the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3775
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]3776<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3777instruction and the variable argument handling intrinsic functions are
3778used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3779
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3780<div class="doc_code">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3781<pre>
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3782define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3783 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3784 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3785 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3786 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3787
3788 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3789 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3790
3791 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3792 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3793 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3794 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3795 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3796
3797 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3798 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3799 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3800}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3801
3802declare void @llvm.va_start(i8*)
3803declare void @llvm.va_copy(i8*, i8*)
3804declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3805</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3806</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3807
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3808</div>
3809
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3810<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3811<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3812 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3813</div>
3814
3815
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3816<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3817<h5>Syntax:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3818<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3819<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3820<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
3821<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
3822href="#i_va_arg">va_arg</a></tt>.</p>
3823
3824<h5>Arguments:</h5>
3825
3826<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
3827
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3828<h5>Semantics:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3829
3830<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
3831macro available in C. In a target-dependent way, it initializes the
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3832<tt>va_list</tt> element to which the argument points, so that the next call to
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3833<tt>va_arg</tt> will produce the first variable argument passed to the function.
3834Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3835last argument of the function as the compiler can figure that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3836
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3837</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3838
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3839<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3840<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3841 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3842</div>
3843
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3844<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3845<h5>Syntax:</h5>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3846<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3847<h5>Overview:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3848
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3849<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3850which has been initialized previously with <tt><a href="#int_va_start">llvm.va_start</a></tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3851or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3852
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3853<h5>Arguments:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3854
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3855<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3856
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3857<h5>Semantics:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3858
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3859<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3860macro available in C. In a target-dependent way, it destroys the
3861<tt>va_list</tt> element to which the argument points. Calls to <a
3862href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
3863<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
3864<tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3865
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3866</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3867
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3868<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3869<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3870 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3871</div>
3872
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3873<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3874
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3875<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3876
3877<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3878 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3879</pre>
3880
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3881<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3882
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3883<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
3884from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3885
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3886<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3887
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3888<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
Andrew Lenharthd0a4c622005-06-22 20:38:11 +0000[diff] [blame]3889The second argument is a pointer to a <tt>va_list</tt> element to copy from.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3890
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3891
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3892<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3893
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3894<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
3895macro available in C. In a target-dependent way, it copies the source
3896<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
3897intrinsic is necessary because the <tt><a href="#int_va_start">
3898llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
3899example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3900
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3901</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3902
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3903<!-- ======================================================================= -->
3904<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3905 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
3906</div>
3907
3908<div class="doc_text">
3909
3910<p>
3911LLVM support for <a href="GarbageCollection.html">Accurate Garbage
3912Collection</a> requires the implementation and generation of these intrinsics.
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3913These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3914stack</a>, as well as garbage collector implementations that require <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3915href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3916Front-ends for type-safe garbage collected languages should generate these
3917intrinsics to make use of the LLVM garbage collectors. For more details, see <a
3918href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
3919</p>
3920</div>
3921
3922<!-- _______________________________________________________________________ -->
3923<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3924 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3925</div>
3926
3927<div class="doc_text">
3928
3929<h5>Syntax:</h5>
3930
3931<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]3932 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3933</pre>
3934
3935<h5>Overview:</h5>
3936
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]3937<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3938the code generator, and allows some metadata to be associated with it.</p>
3939
3940<h5>Arguments:</h5>
3941
3942<p>The first argument specifies the address of a stack object that contains the
3943root pointer. The second pointer (which must be either a constant or a global
3944value address) contains the meta-data to be associated with the root.</p>
3945
3946<h5>Semantics:</h5>
3947
3948<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
3949location. At compile-time, the code generator generates information to allow
3950the runtime to find the pointer at GC safe points.
3951</p>
3952
3953</div>
3954
3955
3956<!-- _______________________________________________________________________ -->
3957<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3958 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3959</div>
3960
3961<div class="doc_text">
3962
3963<h5>Syntax:</h5>
3964
3965<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]3966 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3967</pre>
3968
3969<h5>Overview:</h5>
3970
3971<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
3972locations, allowing garbage collector implementations that require read
3973barriers.</p>
3974
3975<h5>Arguments:</h5>
3976
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3977<p>The second argument is the address to read from, which should be an address
3978allocated from the garbage collector. The first object is a pointer to the
3979start of the referenced object, if needed by the language runtime (otherwise
3980null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3981
3982<h5>Semantics:</h5>
3983
3984<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
3985instruction, but may be replaced with substantially more complex code by the
3986garbage collector runtime, as needed.</p>
3987
3988</div>
3989
3990
3991<!-- _______________________________________________________________________ -->
3992<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3993 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3994</div>
3995
3996<div class="doc_text">
3997
3998<h5>Syntax:</h5>
3999
4000<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4001 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4002</pre>
4003
4004<h5>Overview:</h5>
4005
4006<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
4007locations, allowing garbage collector implementations that require write
4008barriers (such as generational or reference counting collectors).</p>
4009
4010<h5>Arguments:</h5>
4011
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]4012<p>The first argument is the reference to store, the second is the start of the
4013object to store it to, and the third is the address of the field of Obj to
4014store to. If the runtime does not require a pointer to the object, Obj may be
4015null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4016
4017<h5>Semantics:</h5>
4018
4019<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
4020instruction, but may be replaced with substantially more complex code by the
4021garbage collector runtime, as needed.</p>
4022
4023</div>
4024
4025
4026
4027<!-- ======================================================================= -->
4028<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4029 <a name="int_codegen">Code Generator Intrinsics</a>
4030</div>
4031
4032<div class="doc_text">
4033<p>
4034These intrinsics are provided by LLVM to expose special features that may only
4035be implemented with code generator support.
4036</p>
4037
4038</div>
4039
4040<!-- _______________________________________________________________________ -->
4041<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4042 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4043</div>
4044
4045<div class="doc_text">
4046
4047<h5>Syntax:</h5>
4048<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4049 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4050</pre>
4051
4052<h5>Overview:</h5>
4053
4054<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]4055The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
4056target-specific value indicating the return address of the current function
4057or one of its callers.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4058</p>
4059
4060<h5>Arguments:</h5>
4061
4062<p>
4063The argument to this intrinsic indicates which function to return the address
4064for. Zero indicates the calling function, one indicates its caller, etc. The
4065argument is <b>required</b> to be a constant integer value.
4066</p>
4067
4068<h5>Semantics:</h5>
4069
4070<p>
4071The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
4072the return address of the specified call frame, or zero if it cannot be
4073identified. The value returned by this intrinsic is likely to be incorrect or 0
4074for arguments other than zero, so it should only be used for debugging purposes.
4075</p>
4076
4077<p>
4078Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]4079aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4080source-language caller.
4081</p>
4082</div>
4083
4084
4085<!-- _______________________________________________________________________ -->
4086<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4087 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4088</div>
4089
4090<div class="doc_text">
4091
4092<h5>Syntax:</h5>
4093<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4094 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4095</pre>
4096
4097<h5>Overview:</h5>
4098
4099<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]4100The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
4101target-specific frame pointer value for the specified stack frame.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4102</p>
4103
4104<h5>Arguments:</h5>
4105
4106<p>
4107The argument to this intrinsic indicates which function to return the frame
4108pointer for. Zero indicates the calling function, one indicates its caller,
4109etc. The argument is <b>required</b> to be a constant integer value.
4110</p>
4111
4112<h5>Semantics:</h5>
4113
4114<p>
4115The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
4116the frame address of the specified call frame, or zero if it cannot be
4117identified. The value returned by this intrinsic is likely to be incorrect or 0
4118for arguments other than zero, so it should only be used for debugging purposes.
4119</p>
4120
4121<p>
4122Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]4123aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4124source-language caller.
4125</p>
4126</div>
4127
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4128<!-- _______________________________________________________________________ -->
4129<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4130 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4131</div>
4132
4133<div class="doc_text">
4134
4135<h5>Syntax:</h5>
4136<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4137 declare i8 *@llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4138</pre>
4139
4140<h5>Overview:</h5>
4141
4142<p>
4143The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4144the function stack, for use with <a href="#int_stackrestore">
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4145<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
4146features like scoped automatic variable sized arrays in C99.
4147</p>
4148
4149<h5>Semantics:</h5>
4150
4151<p>
4152This intrinsic returns a opaque pointer value that can be passed to <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4153href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4154<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
4155<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
4156state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
4157practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
4158that were allocated after the <tt>llvm.stacksave</tt> was executed.
4159</p>
4160
4161</div>
4162
4163<!-- _______________________________________________________________________ -->
4164<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4165 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4166</div>
4167
4168<div class="doc_text">
4169
4170<h5>Syntax:</h5>
4171<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4172 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4173</pre>
4174
4175<h5>Overview:</h5>
4176
4177<p>
4178The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
4179the function stack to the state it was in when the corresponding <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4180href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4181useful for implementing language features like scoped automatic variable sized
4182arrays in C99.
4183</p>
4184
4185<h5>Semantics:</h5>
4186
4187<p>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4188See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4189</p>
4190
4191</div>
4192
4193
4194<!-- _______________________________________________________________________ -->
4195<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4196 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4197</div>
4198
4199<div class="doc_text">
4200
4201<h5>Syntax:</h5>
4202<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4203 declare void @llvm.prefetch(i8* &lt;address&gt;, i32 &lt;rw&gt;, i32 &lt;locality&gt;)
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4204</pre>
4205
4206<h5>Overview:</h5>
4207
4208
4209<p>
4210The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4211a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
4212no
4213effect on the behavior of the program but can change its performance
Chris Lattner2a615362005-02-28 19:47:14 +0000[diff] [blame]4214characteristics.
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4215</p>
4216
4217<h5>Arguments:</h5>
4218
4219<p>
4220<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
4221determining if the fetch should be for a read (0) or write (1), and
4222<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattneraeffb4a2005-03-07 20:31:38 +0000[diff] [blame]4223locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4224<tt>locality</tt> arguments must be constant integers.
4225</p>
4226
4227<h5>Semantics:</h5>
4228
4229<p>
4230This intrinsic does not modify the behavior of the program. In particular,
4231prefetches cannot trap and do not produce a value. On targets that support this
4232intrinsic, the prefetch can provide hints to the processor cache for better
4233performance.
4234</p>
4235
4236</div>
4237
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4238<!-- _______________________________________________________________________ -->
4239<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4240 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4241</div>
4242
4243<div class="doc_text">
4244
4245<h5>Syntax:</h5>
4246<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4247 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4248</pre>
4249
4250<h5>Overview:</h5>
4251
4252
4253<p>
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4254The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
4255(PC) in a region of
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4256code to simulators and other tools. The method is target specific, but it is
4257expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]4258The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnerd07c3f42005-11-15 06:07:55 +0000[diff] [blame]4259after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb3e7afd2006-03-24 07:16:10 +0000[diff] [blame]4260optimizations. The intended use is to be inserted after optimizations to allow
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4261correlations of simulation runs.
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4262</p>
4263
4264<h5>Arguments:</h5>
4265
4266<p>
4267<tt>id</tt> is a numerical id identifying the marker.
4268</p>
4269
4270<h5>Semantics:</h5>
4271
4272<p>
4273This intrinsic does not modify the behavior of the program. Backends that do not
4274support this intrinisic may ignore it.
4275</p>
4276
4277</div>
4278
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4279<!-- _______________________________________________________________________ -->
4280<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4281 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4282</div>
4283
4284<div class="doc_text">
4285
4286<h5>Syntax:</h5>
4287<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4288 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4289</pre>
4290
4291<h5>Overview:</h5>
4292
4293
4294<p>
4295The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
4296counter register (or similar low latency, high accuracy clocks) on those targets
4297that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
4298As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
4299should only be used for small timings.
4300</p>
4301
4302<h5>Semantics:</h5>
4303
4304<p>
4305When directly supported, reading the cycle counter should not modify any memory.
4306Implementations are allowed to either return a application specific value or a
4307system wide value. On backends without support, this is lowered to a constant 0.
4308</p>
4309
4310</div>
4311
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4312<!-- ======================================================================= -->
4313<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4314 <a name="int_libc">Standard C Library Intrinsics</a>
4315</div>
4316
4317<div class="doc_text">
4318<p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4319LLVM provides intrinsics for a few important standard C library functions.
4320These intrinsics allow source-language front-ends to pass information about the
4321alignment of the pointer arguments to the code generator, providing opportunity
4322for more efficient code generation.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4323</p>
4324
4325</div>
4326
4327<!-- _______________________________________________________________________ -->
4328<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4329 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4330</div>
4331
4332<div class="doc_text">
4333
4334<h5>Syntax:</h5>
4335<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4336 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4337 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4338 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4339 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4340</pre>
4341
4342<h5>Overview:</h5>
4343
4344<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4345The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4346location to the destination location.
4347</p>
4348
4349<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4350Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4351intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4352</p>
4353
4354<h5>Arguments:</h5>
4355
4356<p>
4357The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4358the source. The third argument is an integer argument
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4359specifying the number of bytes to copy, and the fourth argument is the alignment
4360of the source and destination locations.
4361</p>
4362
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4363<p>
4364If the call to this intrinisic has an alignment value that is not 0 or 1, then
Chris Lattnerf0afc2c2006-03-04 00:02:10 +0000[diff] [blame]4365the caller guarantees that both the source and destination pointers are aligned
4366to that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4367</p>
4368
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4369<h5>Semantics:</h5>
4370
4371<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4372The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4373location to the destination location, which are not allowed to overlap. It
4374copies "len" bytes of memory over. If the argument is known to be aligned to
4375some boundary, this can be specified as the fourth argument, otherwise it should
4376be set to 0 or 1.
4377</p>
4378</div>
4379
4380
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4381<!-- _______________________________________________________________________ -->
4382<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4383 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4384</div>
4385
4386<div class="doc_text">
4387
4388<h5>Syntax:</h5>
4389<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4390 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4391 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4392 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4393 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4394</pre>
4395
4396<h5>Overview:</h5>
4397
4398<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4399The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
4400location to the destination location. It is similar to the
4401'<tt>llvm.memcmp</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4402</p>
4403
4404<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4405Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
4406intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4407</p>
4408
4409<h5>Arguments:</h5>
4410
4411<p>
4412The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4413the source. The third argument is an integer argument
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4414specifying the number of bytes to copy, and the fourth argument is the alignment
4415of the source and destination locations.
4416</p>
4417
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4418<p>
4419If the call to this intrinisic has an alignment value that is not 0 or 1, then
Chris Lattnerf0afc2c2006-03-04 00:02:10 +0000[diff] [blame]4420the caller guarantees that the source and destination pointers are aligned to
4421that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4422</p>
4423
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4424<h5>Semantics:</h5>
4425
4426<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4427The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4428location to the destination location, which may overlap. It
4429copies "len" bytes of memory over. If the argument is known to be aligned to
4430some boundary, this can be specified as the fourth argument, otherwise it should
4431be set to 0 or 1.
4432</p>
4433</div>
4434
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4435
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4436<!-- _______________________________________________________________________ -->
4437<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4438 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4439</div>
4440
4441<div class="doc_text">
4442
4443<h5>Syntax:</h5>
4444<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4445 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4446 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4447 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4448 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4449</pre>
4450
4451<h5>Overview:</h5>
4452
4453<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4454The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4455byte value.
4456</p>
4457
4458<p>
4459Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
4460does not return a value, and takes an extra alignment argument.
4461</p>
4462
4463<h5>Arguments:</h5>
4464
4465<p>
4466The first argument is a pointer to the destination to fill, the second is the
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4467byte value to fill it with, the third argument is an integer
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4468argument specifying the number of bytes to fill, and the fourth argument is the
4469known alignment of destination location.
4470</p>
4471
4472<p>
4473If the call to this intrinisic has an alignment value that is not 0 or 1, then
Chris Lattnerf0afc2c2006-03-04 00:02:10 +0000[diff] [blame]4474the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4475</p>
4476
4477<h5>Semantics:</h5>
4478
4479<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4480The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
4481the
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4482destination location. If the argument is known to be aligned to some boundary,
4483this can be specified as the fourth argument, otherwise it should be set to 0 or
44841.
4485</p>
4486</div>
4487
4488
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4489<!-- _______________________________________________________________________ -->
4490<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4491 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4492</div>
4493
4494<div class="doc_text">
4495
4496<h5>Syntax:</h5>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]4497<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame^]4498floating point or vector of floating point type. Not all targets support all
4499types however.
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4500<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]4501 declare float @llvm.sqrt.f32(float %Val)
4502 declare double @llvm.sqrt.f64(double %Val)
4503 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
4504 declare fp128 @llvm.sqrt.f128(fp128 %Val)
4505 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4506</pre>
4507
4508<h5>Overview:</h5>
4509
4510<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4511The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame^]4512returning the same value as the libm '<tt>sqrt</tt>' functions would. Unlike
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4513<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
4514negative numbers (which allows for better optimization).
4515</p>
4516
4517<h5>Arguments:</h5>
4518
4519<p>
4520The argument and return value are floating point numbers of the same type.
4521</p>
4522
4523<h5>Semantics:</h5>
4524
4525<p>
Dan Gohmand6257fe2007-07-16 14:37:41 +0000[diff] [blame]4526This function returns the sqrt of the specified operand if it is a nonnegative
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4527floating point number.
4528</p>
4529</div>
4530
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4531<!-- _______________________________________________________________________ -->
4532<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4533 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4534</div>
4535
4536<div class="doc_text">
4537
4538<h5>Syntax:</h5>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]4539<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame^]4540floating point or vector of floating point type. Not all targets support all
4541types however.
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4542<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]4543 declare float @llvm.powi.f32(float %Val, i32 %power)
4544 declare double @llvm.powi.f64(double %Val, i32 %power)
4545 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
4546 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
4547 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4548</pre>
4549
4550<h5>Overview:</h5>
4551
4552<p>
4553The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
4554specified (positive or negative) power. The order of evaluation of
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame^]4555multiplications is not defined. When a vector of floating point type is
4556used, the second argument remains a scalar integer value.
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4557</p>
4558
4559<h5>Arguments:</h5>
4560
4561<p>
4562The second argument is an integer power, and the first is a value to raise to
4563that power.
4564</p>
4565
4566<h5>Semantics:</h5>
4567
4568<p>
4569This function returns the first value raised to the second power with an
4570unspecified sequence of rounding operations.</p>
4571</div>
4572
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame^]4573<!-- _______________________________________________________________________ -->
4574<div class="doc_subsubsection">
4575 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
4576</div>
4577
4578<div class="doc_text">
4579
4580<h5>Syntax:</h5>
4581<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
4582floating point or vector of floating point type. Not all targets support all
4583types however.
4584<pre>
4585 declare float @llvm.sin.f32(float %Val)
4586 declare double @llvm.sin.f64(double %Val)
4587 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
4588 declare fp128 @llvm.sin.f128(fp128 %Val)
4589 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
4590</pre>
4591
4592<h5>Overview:</h5>
4593
4594<p>
4595The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
4596</p>
4597
4598<h5>Arguments:</h5>
4599
4600<p>
4601The argument and return value are floating point numbers of the same type.
4602</p>
4603
4604<h5>Semantics:</h5>
4605
4606<p>
4607This function returns the sine of the specified operand, returning the
4608same values as the libm <tt>sin</tt> functions would, and handles error
4609conditions in the same way, unless the --enable-unsafe-fp-math is enabled
4610during code generation, in which case the result may have different
4611precision and if any errors occur the behavior is undefined.</p>
4612</div>
4613
4614<!-- _______________________________________________________________________ -->
4615<div class="doc_subsubsection">
4616 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
4617</div>
4618
4619<div class="doc_text">
4620
4621<h5>Syntax:</h5>
4622<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
4623floating point or vector of floating point type. Not all targets support all
4624types however.
4625<pre>
4626 declare float @llvm.cos.f32(float %Val)
4627 declare double @llvm.cos.f64(double %Val)
4628 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
4629 declare fp128 @llvm.cos.f128(fp128 %Val)
4630 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
4631</pre>
4632
4633<h5>Overview:</h5>
4634
4635<p>
4636The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
4637</p>
4638
4639<h5>Arguments:</h5>
4640
4641<p>
4642The argument and return value are floating point numbers of the same type.
4643</p>
4644
4645<h5>Semantics:</h5>
4646
4647<p>
4648This function returns the cosine of the specified operand, returning the
4649same values as the libm <tt>cos</tt> functions would, and handles error
4650conditions in the same way, unless the --enable-unsafe-fp-math is enabled
4651during code generation, in which case the result may have different
4652precision and if any errors occur the behavior is undefined.</p>
4653</div>
4654
4655<!-- _______________________________________________________________________ -->
4656<div class="doc_subsubsection">
4657 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
4658</div>
4659
4660<div class="doc_text">
4661
4662<h5>Syntax:</h5>
4663<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
4664floating point or vector of floating point type. Not all targets support all
4665types however.
4666<pre>
4667 declare float @llvm.pow.f32(float %Val, float %Power)
4668 declare double @llvm.pow.f64(double %Val, double %Power)
4669 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
4670 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
4671 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
4672</pre>
4673
4674<h5>Overview:</h5>
4675
4676<p>
4677The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
4678specified (positive or negative) power.
4679</p>
4680
4681<h5>Arguments:</h5>
4682
4683<p>
4684The second argument is a floating point power, and the first is a value to
4685raise to that power.
4686</p>
4687
4688<h5>Semantics:</h5>
4689
4690<p>
4691This function returns the first value raised to the second power,
4692returning the
4693same values as the libm <tt>pow</tt> functions would, and handles error
4694conditions in the same way, unless the --enable-unsafe-fp-math is enabled
4695during code generation, in which case the result may have different
4696precision and if any errors occur the behavior is undefined.</p>
4697</div>
4698
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4699
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4700<!-- ======================================================================= -->
4701<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4702 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4703</div>
4704
4705<div class="doc_text">
4706<p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4707LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4708These allow efficient code generation for some algorithms.
4709</p>
4710
4711</div>
4712
4713<!-- _______________________________________________________________________ -->
4714<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4715 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4716</div>
4717
4718<div class="doc_text">
4719
4720<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4721<p>This is an overloaded intrinsic function. You can use bswap on any integer
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4722type that is an even number of bytes (i.e. BitWidth % 16 == 0).
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4723<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4724 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
4725 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
4726 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4727</pre>
4728
4729<h5>Overview:</h5>
4730
4731<p>
Reid Spencer338ea092007-04-02 02:25:19 +0000[diff] [blame]4732The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4733values with an even number of bytes (positive multiple of 16 bits). These are
4734useful for performing operations on data that is not in the target's native
4735byte order.
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4736</p>
4737
4738<h5>Semantics:</h5>
4739
4740<p>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4741The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4742and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
4743intrinsic returns an i32 value that has the four bytes of the input i32
4744swapped, so that if the input bytes are numbered 0, 1, 2, 3 then the returned
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4745i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
4746<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4747additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4748</p>
4749
4750</div>
4751
4752<!-- _______________________________________________________________________ -->
4753<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4754 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4755</div>
4756
4757<div class="doc_text">
4758
4759<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4760<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
4761width. Not all targets support all bit widths however.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4762<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4763 declare i8 @llvm.ctpop.i8 (i8 &lt;src&gt;)
4764 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4765 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4766 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
4767 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4768</pre>
4769
4770<h5>Overview:</h5>
4771
4772<p>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4773The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
4774value.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4775</p>
4776
4777<h5>Arguments:</h5>
4778
4779<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]4780The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4781integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4782</p>
4783
4784<h5>Semantics:</h5>
4785
4786<p>
4787The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
4788</p>
4789</div>
4790
4791<!-- _______________________________________________________________________ -->
4792<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]4793 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4794</div>
4795
4796<div class="doc_text">
4797
4798<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4799<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
4800integer bit width. Not all targets support all bit widths however.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4801<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4802 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
4803 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4804 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4805 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
4806 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4807</pre>
4808
4809<h5>Overview:</h5>
4810
4811<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4812The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
4813leading zeros in a variable.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4814</p>
4815
4816<h5>Arguments:</h5>
4817
4818<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]4819The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4820integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4821</p>
4822
4823<h5>Semantics:</h5>
4824
4825<p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4826The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
4827in a variable. If the src == 0 then the result is the size in bits of the type
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4828of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4829</p>
4830</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4831
4832
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4833
4834<!-- _______________________________________________________________________ -->
4835<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]4836 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4837</div>
4838
4839<div class="doc_text">
4840
4841<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4842<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
4843integer bit width. Not all targets support all bit widths however.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4844<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4845 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
4846 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4847 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4848 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
4849 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4850</pre>
4851
4852<h5>Overview:</h5>
4853
4854<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4855The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
4856trailing zeros.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4857</p>
4858
4859<h5>Arguments:</h5>
4860
4861<p>
4862The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4863integer type. The return type must match the argument type.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4864</p>
4865
4866<h5>Semantics:</h5>
4867
4868<p>
4869The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
4870in a variable. If the src == 0 then the result is the size in bits of the type
4871of src. For example, <tt>llvm.cttz(2) = 1</tt>.
4872</p>
4873</div>
4874
Reid Spencer497d93e2007-04-01 08:27:01 +0000[diff] [blame]4875<!-- _______________________________________________________________________ -->
4876<div class="doc_subsubsection">
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]4877 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4878</div>
4879
4880<div class="doc_text">
4881
4882<h5>Syntax:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]4883<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4884on any integer bit width.
4885<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4886 declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
4887 declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4888</pre>
4889
4890<h5>Overview:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]4891<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4892range of bits from an integer value and returns them in the same bit width as
4893the original value.</p>
4894
4895<h5>Arguments:</h5>
4896<p>The first argument, <tt>%val</tt> and the result may be integer types of
4897any bit width but they must have the same bit width. The second and third
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4898arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4899
4900<h5>Semantics:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]4901<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4902of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
4903<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
4904operates in forward mode.</p>
4905<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
4906right by <tt>%loBit</tt> bits and then ANDing it with a mask with
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4907only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
4908<ol>
4909 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
4910 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
4911 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
4912 to determine the number of bits to retain.</li>
4913 <li>A mask of the retained bits is created by shifting a -1 value.</li>
4914 <li>The mask is ANDed with <tt>%val</tt> to produce the result.
4915</ol>
Reid Spencerd6a85b52007-05-14 16:14:57 +0000[diff] [blame]4916<p>In reverse mode, a similar computation is made except that the bits are
4917returned in the reverse order. So, for example, if <tt>X</tt> has the value
4918<tt>i16 0x0ACF (101011001111)</tt> and we apply
4919<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
4920<tt>i16 0x0026 (000000100110)</tt>.</p>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4921</div>
4922
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]4923<div class="doc_subsubsection">
4924 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
4925</div>
4926
4927<div class="doc_text">
4928
4929<h5>Syntax:</h5>
4930<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
4931on any integer bit width.
4932<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4933 declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
4934 declare i29 @llvm.part.set.i29.i9 (i29 %val, i9 %repl, i32 %lo, i32 %hi)
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]4935</pre>
4936
4937<h5>Overview:</h5>
4938<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
4939of bits in an integer value with another integer value. It returns the integer
4940with the replaced bits.</p>
4941
4942<h5>Arguments:</h5>
4943<p>The first argument, <tt>%val</tt> and the result may be integer types of
4944any bit width but they must have the same bit width. <tt>%val</tt> is the value
4945whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
4946integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
4947type since they specify only a bit index.</p>
4948
4949<h5>Semantics:</h5>
4950<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
4951of operation: forwards and reverse. If <tt>%lo</tt> is greater than
4952<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
4953operates in forward mode.</p>
4954<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
4955truncating it down to the size of the replacement area or zero extending it
4956up to that size.</p>
4957<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
4958are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
4959in <tt>%repl</tt> replaces the <tt>%lo</tt>th bit in <tt>%val</tt> and etc. up
4960to the <tt>%hi</tt>th bit.
Reid Spencerc6749c42007-05-14 16:50:20 +0000[diff] [blame]4961<p>In reverse mode, a similar computation is made except that the bits are
4962reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
4963<tt>%hi</tt> bit in <tt>%val</tt> and etc. down to the <tt>%lo</tt>th bit.
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]4964<h5>Examples:</h5>
4965<pre>
Reid Spencerf0dbf642007-04-12 01:03:03 +0000[diff] [blame]4966 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
Reid Spencerc6749c42007-05-14 16:50:20 +0000[diff] [blame]4967 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
4968 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
4969 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
Reid Spencerf0dbf642007-04-12 01:03:03 +0000[diff] [blame]4970 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]4971</pre>
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]4972</div>
4973
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4974<!-- ======================================================================= -->
4975<div class="doc_subsection">
4976 <a name="int_debugger">Debugger Intrinsics</a>
4977</div>
4978
4979<div class="doc_text">
4980<p>
4981The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
4982are described in the <a
4983href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
4984Debugging</a> document.
4985</p>
4986</div>
4987
4988
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]4989<!-- ======================================================================= -->
4990<div class="doc_subsection">
4991 <a name="int_eh">Exception Handling Intrinsics</a>
4992</div>
4993
4994<div class="doc_text">
4995<p> The LLVM exception handling intrinsics (which all start with
4996<tt>llvm.eh.</tt> prefix), are described in the <a
4997href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
4998Handling</a> document. </p>
4999</div>
5000
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5001<!-- ======================================================================= -->
5002<div class="doc_subsection">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5003 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5004</div>
5005
5006<div class="doc_text">
5007<p>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5008 This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5009 the <tt>nest</tt> attribute, from a function. The result is a callable
5010 function pointer lacking the nest parameter - the caller does not need
5011 to provide a value for it. Instead, the value to use is stored in
5012 advance in a "trampoline", a block of memory usually allocated
5013 on the stack, which also contains code to splice the nest value into the
5014 argument list. This is used to implement the GCC nested function address
5015 extension.
5016</p>
5017<p>
5018 For example, if the function is
5019 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
Bill Wendling03295ca2007-09-22 09:23:55 +0000[diff] [blame]5020 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as follows:</p>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5021<pre>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5022 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
5023 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
5024 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
5025 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5026</pre>
Bill Wendling03295ca2007-09-22 09:23:55 +0000[diff] [blame]5027 <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
5028 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5029</div>
5030
5031<!-- _______________________________________________________________________ -->
5032<div class="doc_subsubsection">
5033 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
5034</div>
5035<div class="doc_text">
5036<h5>Syntax:</h5>
5037<pre>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5038declare i8* @llvm.init.trampoline(i8* &lt;tramp&gt;, i8* &lt;func&gt;, i8* &lt;nval&gt;)
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5039</pre>
5040<h5>Overview:</h5>
5041<p>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5042 This fills the memory pointed to by <tt>tramp</tt> with code
5043 and returns a function pointer suitable for executing it.
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5044</p>
5045<h5>Arguments:</h5>
5046<p>
5047 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
5048 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
5049 and sufficiently aligned block of memory; this memory is written to by the
Duncan Sandsc00c2ba2007-08-22 23:39:54 +0000[diff] [blame]5050 intrinsic. Note that the size and the alignment are target-specific - LLVM
5051 currently provides no portable way of determining them, so a front-end that
5052 generates this intrinsic needs to have some target-specific knowledge.
5053 The <tt>func</tt> argument must hold a function bitcast to an <tt>i8*</tt>.
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5054</p>
5055<h5>Semantics:</h5>
5056<p>
5057 The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5058 dependent code, turning it into a function. A pointer to this function is
5059 returned, but needs to be bitcast to an
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5060 <a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5061 before being called. The new function's signature is the same as that of
5062 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
5063 removed. At most one such <tt>nest</tt> argument is allowed, and it must be
5064 of pointer type. Calling the new function is equivalent to calling
5065 <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
5066 missing <tt>nest</tt> argument. If, after calling
5067 <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
5068 modified, then the effect of any later call to the returned function pointer is
5069 undefined.
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5070</p>
5071</div>
5072
5073<!-- ======================================================================= -->
5074<div class="doc_subsection">
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5075 <a name="int_general">General Intrinsics</a>
5076</div>
5077
5078<div class="doc_text">
5079<p> This class of intrinsics is designed to be generic and has
5080no specific purpose. </p>
5081</div>
5082
5083<!-- _______________________________________________________________________ -->
5084<div class="doc_subsubsection">
5085 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
5086</div>
5087
5088<div class="doc_text">
5089
5090<h5>Syntax:</h5>
5091<pre>
Tanya Lattnerd2e84422007-06-18 23:42:37 +0000[diff] [blame]5092 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5093</pre>
5094
5095<h5>Overview:</h5>
5096
5097<p>
5098The '<tt>llvm.var.annotation</tt>' intrinsic
5099</p>
5100
5101<h5>Arguments:</h5>
5102
5103<p>
Tanya Lattnerd2e84422007-06-18 23:42:37 +0000[diff] [blame]5104The first argument is a pointer to a value, the second is a pointer to a
5105global string, the third is a pointer to a global string which is the source
5106file name, and the last argument is the line number.
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5107</p>
5108
5109<h5>Semantics:</h5>
5110
5111<p>
5112This intrinsic allows annotation of local variables with arbitrary strings.
5113This can be useful for special purpose optimizations that want to look for these
5114 annotations. These have no other defined use, they are ignored by code
5115 generation and optimization.
5116</div>
5117
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5118<!-- _______________________________________________________________________ -->
5119<div class="doc_subsubsection">
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]5120 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5121</div>
5122
5123<div class="doc_text">
5124
5125<h5>Syntax:</h5>
Tanya Lattner39cfba62007-09-21 23:56:27 +0000[diff] [blame]5126<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
5127any integer bit width.
5128</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5129<pre>
Tanya Lattnerd3989a82007-09-22 00:03:01 +0000[diff] [blame]5130 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5131 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5132 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5133 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5134 declare i256 @llvm.annotation.i256(i256 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5135</pre>
5136
5137<h5>Overview:</h5>
Tanya Lattner39cfba62007-09-21 23:56:27 +0000[diff] [blame]5138
5139<p>
5140The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5141</p>
5142
5143<h5>Arguments:</h5>
5144
5145<p>
5146The first argument is an integer value (result of some expression),
5147the second is a pointer to a global string, the third is a pointer to a global
5148string which is the source file name, and the last argument is the line number.
Tanya Lattner39cfba62007-09-21 23:56:27 +0000[diff] [blame]5149It returns the value of the first argument.
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5150</p>
5151
5152<h5>Semantics:</h5>
5153
5154<p>
5155This intrinsic allows annotations to be put on arbitrary expressions
5156with arbitrary strings. This can be useful for special purpose optimizations
5157that want to look for these annotations. These have no other defined use, they
5158are ignored by code generation and optimization.
5159</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]5160
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5161<!-- *********************************************************************** -->
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Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]5163<address>
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5168
5169 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]5170 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]5171 Last modified: $Date$
5172</address>
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