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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 03295ca4e6c17772d046ec216972c776649d6ad9 / . / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
Reid Spencer3921c742004-08-26 20:44:00 +0000[diff] [blame]6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
8 <meta name="description"
9 content="LLVM Assembly Language Reference Manual.">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]10 <link rel="stylesheet" href="llvm.css" type="text/css">
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>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]180 </ol>
181 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]182 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]183 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]184 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]185 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
186 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
187 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]188 <li><a href="#int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic </a></li>
189 <li><a href="#int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]190 </ol>
191 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]192 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]193 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Chandler Carruth2eb93b32007-07-20 19:34:37 +0000[diff] [blame]194 <li><a href="#int_atomics">Atomic Operations and Synchronization Intrinsics</a>
195 <ol>
196 <li><a href="#int_lcs">'<tt>llvm.atomic.lcs.*</tt>' Intrinsic</a></li>
197 <li><a href="#int_ls">'<tt>llvm.atomic.ls.*</tt>' Intrinsic</a></li>
198 <li><a href="#int_las">'<tt>llvm.atomic.las.*</tt>' Intrinsic</a></li>
199 <li><a href="#int_lss">'<tt>llvm.atomic.lss.*</tt>' Intrinsic</a></li>
200 <li><a href="#int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a></li>
201 </ol>
202 </li>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]203 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]204 <ol>
205 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]206 </ol>
207 </li>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]208 <li><a href="#int_general">General intrinsics</a>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]209 <ol>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]210 <li><a href="#int_var_annotation">
Tanya Lattner91d0b882007-09-22 00:01:26 +0000[diff] [blame]211 <tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]212 </ol>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]213 <ol>
214 <li><a href="#int_annotation">
Tanya Lattner91d0b882007-09-22 00:01:26 +0000[diff] [blame]215 <tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]216 </ol>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]217 </li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]218 </ol>
219 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]220</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]221
222<div class="doc_author">
223 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
224 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]225</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]226
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]227<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]228<div class="doc_section"> <a name="abstract">Abstract </a></div>
229<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]230
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]231<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]232<p>This document is a reference manual for the LLVM assembly language.
233LLVM is an SSA based representation that provides type safety,
234low-level operations, flexibility, and the capability of representing
235'all' high-level languages cleanly. It is the common code
236representation used throughout all phases of the LLVM compilation
237strategy.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]238</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]239
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]240<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]241<div class="doc_section"> <a name="introduction">Introduction</a> </div>
242<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]243
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]244<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]245
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]246<p>The LLVM code representation is designed to be used in three
Gabor Greif04367bf2007-07-06 22:07:22 +0000[diff] [blame]247different forms: as an in-memory compiler IR, as an on-disk bitcode
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]248representation (suitable for fast loading by a Just-In-Time compiler),
249and as a human readable assembly language representation. This allows
250LLVM to provide a powerful intermediate representation for efficient
251compiler transformations and analysis, while providing a natural means
252to debug and visualize the transformations. The three different forms
253of LLVM are all equivalent. This document describes the human readable
254representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]255
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]256<p>The LLVM representation aims to be light-weight and low-level
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]257while being expressive, typed, and extensible at the same time. It
258aims to be a "universal IR" of sorts, by being at a low enough level
259that high-level ideas may be cleanly mapped to it (similar to how
260microprocessors are "universal IR's", allowing many source languages to
261be mapped to them). By providing type information, LLVM can be used as
262the target of optimizations: for example, through pointer analysis, it
263can be proven that a C automatic variable is never accessed outside of
264the current function... allowing it to be promoted to a simple SSA
265value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]266
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]267</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]268
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]269<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]270<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]271
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]272<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]273
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]274<p>It is important to note that this document describes 'well formed'
275LLVM assembly language. There is a difference between what the parser
276accepts and what is considered 'well formed'. For example, the
277following instruction is syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]278
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]279<div class="doc_code">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]280<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]281%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]282</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]283</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]284
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]285<p>...because the definition of <tt>%x</tt> does not dominate all of
286its uses. The LLVM infrastructure provides a verification pass that may
287be used to verify that an LLVM module is well formed. This pass is
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]288automatically run by the parser after parsing input assembly and by
Gabor Greif04367bf2007-07-06 22:07:22 +0000[diff] [blame]289the optimizer before it outputs bitcode. The violations pointed out
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]290by the verifier pass indicate bugs in transformation passes or input to
291the parser.</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]292</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]293
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]294<!-- Describe the typesetting conventions here. -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]295
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]296<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]297<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]298<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]299
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]300<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]301
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]302 <p>LLVM identifiers come in two basic types: global and local. Global
303 identifiers (functions, global variables) begin with the @ character. Local
304 identifiers (register names, types) begin with the % character. Additionally,
305 there are three different formats for identifiers, for different purposes:
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]306
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]307<ol>
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]308 <li>Named values are represented as a string of characters with their prefix.
309 For example, %foo, @DivisionByZero, %a.really.long.identifier. The actual
310 regular expression used is '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]311 Identifiers which require other characters in their names can be surrounded
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]312 with quotes. In this way, anything except a <tt>&quot;</tt> character can
313 be used in a named value.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]314
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]315 <li>Unnamed values are represented as an unsigned numeric value with their
316 prefix. For example, %12, @2, %44.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]317
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]318 <li>Constants, which are described in a <a href="#constants">section about
319 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]320</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]321
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]322<p>LLVM requires that values start with a prefix for two reasons: Compilers
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]323don't need to worry about name clashes with reserved words, and the set of
324reserved words may be expanded in the future without penalty. Additionally,
325unnamed identifiers allow a compiler to quickly come up with a temporary
326variable without having to avoid symbol table conflicts.</p>
327
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]328<p>Reserved words in LLVM are very similar to reserved words in other
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]329languages. There are keywords for different opcodes
330('<tt><a href="#i_add">add</a></tt>',
331 '<tt><a href="#i_bitcast">bitcast</a></tt>',
332 '<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]333href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]334and others. These reserved words cannot conflict with variable names, because
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]335none of them start with a prefix character ('%' or '@').</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]336
337<p>Here is an example of LLVM code to multiply the integer variable
338'<tt>%X</tt>' by 8:</p>
339
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]340<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]341
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]342<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]343<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]344%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]345</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]346</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]347
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]348<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]349
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]350<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]351<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]352%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]353</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]354</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]355
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]356<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]357
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]358<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]359<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]360<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
361<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
362%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]363</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]364</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]365
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]366<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
367important lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]368
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]369<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]370
371 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
372 line.</li>
373
374 <li>Unnamed temporaries are created when the result of a computation is not
375 assigned to a named value.</li>
376
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]377 <li>Unnamed temporaries are numbered sequentially</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]378
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]379</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]380
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]381<p>...and it also shows a convention that we follow in this document. When
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]382demonstrating instructions, we will follow an instruction with a comment that
383defines the type and name of value produced. Comments are shown in italic
384text.</p>
385
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]386</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]387
388<!-- *********************************************************************** -->
389<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
390<!-- *********************************************************************** -->
391
392<!-- ======================================================================= -->
393<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
394</div>
395
396<div class="doc_text">
397
398<p>LLVM programs are composed of "Module"s, each of which is a
399translation unit of the input programs. Each module consists of
400functions, global variables, and symbol table entries. Modules may be
401combined together with the LLVM linker, which merges function (and
402global variable) definitions, resolves forward declarations, and merges
403symbol table entries. Here is an example of the "hello world" module:</p>
404
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]405<div class="doc_code">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]406<pre><i>; Declare the string constant as a global constant...</i>
Chris Lattnera89e5f12007-06-12 17:00:26 +0000[diff] [blame]407<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
408 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]409
410<i>; External declaration of the puts function</i>
Chris Lattnera89e5f12007-06-12 17:00:26 +0000[diff] [blame]411<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]412
413<i>; Definition of main function</i>
Chris Lattnera89e5f12007-06-12 17:00:26 +0000[diff] [blame]414define i32 @main() { <i>; i32()* </i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]415 <i>; Convert [13x i8 ]* to i8 *...</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]416 %cast210 = <a
Chris Lattner6c0955b2007-06-12 17:01:15 +0000[diff] [blame]417 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]418
419 <i>; Call puts function to write out the string to stdout...</i>
420 <a
Chris Lattnera89e5f12007-06-12 17:00:26 +0000[diff] [blame]421 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]422 <a
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]423 href="#i_ret">ret</a> i32 0<br>}<br>
424</pre>
425</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]426
427<p>This example is made up of a <a href="#globalvars">global variable</a>
428named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
429function, and a <a href="#functionstructure">function definition</a>
430for "<tt>main</tt>".</p>
431
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]432<p>In general, a module is made up of a list of global values,
433where both functions and global variables are global values. Global values are
434represented by a pointer to a memory location (in this case, a pointer to an
435array of char, and a pointer to a function), and have one of the following <a
436href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]437
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]438</div>
439
440<!-- ======================================================================= -->
441<div class="doc_subsection">
442 <a name="linkage">Linkage Types</a>
443</div>
444
445<div class="doc_text">
446
447<p>
448All Global Variables and Functions have one of the following types of linkage:
449</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]450
451<dl>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]452
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]453 <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]454
455 <dd>Global values with internal linkage are only directly accessible by
456 objects in the current module. In particular, linking code into a module with
457 an internal global value may cause the internal to be renamed as necessary to
458 avoid collisions. Because the symbol is internal to the module, all
459 references can be updated. This corresponds to the notion of the
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]460 '<tt>static</tt>' keyword in C.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]461 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]462
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]463 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]464
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]465 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
466 the same name when linkage occurs. This is typically used to implement
467 inline functions, templates, or other code which must be generated in each
468 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
469 allowed to be discarded.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]470 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]471
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]472 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]473
474 <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage,
475 except that unreferenced <tt>weak</tt> globals may not be discarded. This is
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]476 used for globals that may be emitted in multiple translation units, but that
477 are not guaranteed to be emitted into every translation unit that uses them.
478 One example of this are common globals in C, such as "<tt>int X;</tt>" at
479 global scope.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]480 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]481
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]482 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]483
484 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
485 pointer to array type. When two global variables with appending linkage are
486 linked together, the two global arrays are appended together. This is the
487 LLVM, typesafe, equivalent of having the system linker append together
488 "sections" with identical names when .o files are linked.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]489 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]490
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]491 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
492 <dd>The semantics of this linkage follow the ELF model: the symbol is weak
493 until linked, if not linked, the symbol becomes null instead of being an
494 undefined reference.
495 </dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]496
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]497 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]498
499 <dd>If none of the above identifiers are used, the global is externally
500 visible, meaning that it participates in linkage and can be used to resolve
501 external symbol references.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]502 </dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]503</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]504
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]505 <p>
506 The next two types of linkage are targeted for Microsoft Windows platform
507 only. They are designed to support importing (exporting) symbols from (to)
508 DLLs.
509 </p>
510
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]511 <dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]512 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
513
514 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
515 or variable via a global pointer to a pointer that is set up by the DLL
516 exporting the symbol. On Microsoft Windows targets, the pointer name is
517 formed by combining <code>_imp__</code> and the function or variable name.
518 </dd>
519
520 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
521
522 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
523 pointer to a pointer in a DLL, so that it can be referenced with the
524 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
525 name is formed by combining <code>_imp__</code> and the function or variable
526 name.
527 </dd>
528
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]529</dl>
530
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]531<p><a name="linkage_external"></a>For example, since the "<tt>.LC0</tt>"
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]532variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
533variable and was linked with this one, one of the two would be renamed,
534preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
535external (i.e., lacking any linkage declarations), they are accessible
Reid Spencerac8d2762007-01-05 00:59:10 +0000[diff] [blame]536outside of the current module.</p>
537<p>It is illegal for a function <i>declaration</i>
538to have any linkage type other than "externally visible", <tt>dllimport</tt>,
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]539or <tt>extern_weak</tt>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]540<p>Aliases can have only <tt>external</tt>, <tt>internal</tt> and <tt>weak</tt>
541linkages.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]542</div>
543
544<!-- ======================================================================= -->
545<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]546 <a name="callingconv">Calling Conventions</a>
547</div>
548
549<div class="doc_text">
550
551<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
552and <a href="#i_invoke">invokes</a> can all have an optional calling convention
553specified for the call. The calling convention of any pair of dynamic
554caller/callee must match, or the behavior of the program is undefined. The
555following calling conventions are supported by LLVM, and more may be added in
556the future:</p>
557
558<dl>
559 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
560
561 <dd>This calling convention (the default if no other calling convention is
562 specified) matches the target C calling conventions. This calling convention
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]563 supports varargs function calls and tolerates some mismatch in the declared
Reid Spencerc28d2bc2006-12-31 21:30:18 +0000[diff] [blame]564 prototype and implemented declaration of the function (as does normal C).
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]565 </dd>
566
567 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
568
569 <dd>This calling convention attempts to make calls as fast as possible
570 (e.g. by passing things in registers). This calling convention allows the
571 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner8cdc5bc2005-05-06 23:08:23 +0000[diff] [blame]572 without having to conform to an externally specified ABI. Implementations of
573 this convention should allow arbitrary tail call optimization to be supported.
574 This calling convention does not support varargs and requires the prototype of
575 all callees to exactly match the prototype of the function definition.
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]576 </dd>
577
578 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
579
580 <dd>This calling convention attempts to make code in the caller as efficient
581 as possible under the assumption that the call is not commonly executed. As
582 such, these calls often preserve all registers so that the call does not break
583 any live ranges in the caller side. This calling convention does not support
584 varargs and requires the prototype of all callees to exactly match the
585 prototype of the function definition.
586 </dd>
587
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]588 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]589
590 <dd>Any calling convention may be specified by number, allowing
591 target-specific calling conventions to be used. Target specific calling
592 conventions start at 64.
593 </dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]594</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]595
596<p>More calling conventions can be added/defined on an as-needed basis, to
597support pascal conventions or any other well-known target-independent
598convention.</p>
599
600</div>
601
602<!-- ======================================================================= -->
603<div class="doc_subsection">
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]604 <a name="visibility">Visibility Styles</a>
605</div>
606
607<div class="doc_text">
608
609<p>
610All Global Variables and Functions have one of the following visibility styles:
611</p>
612
613<dl>
614 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
615
616 <dd>On ELF, default visibility means that the declaration is visible to other
617 modules and, in shared libraries, means that the declared entity may be
618 overridden. On Darwin, default visibility means that the declaration is
619 visible to other modules. Default visibility corresponds to "external
620 linkage" in the language.
621 </dd>
622
623 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
624
625 <dd>Two declarations of an object with hidden visibility refer to the same
626 object if they are in the same shared object. Usually, hidden visibility
627 indicates that the symbol will not be placed into the dynamic symbol table,
628 so no other module (executable or shared library) can reference it
629 directly.
630 </dd>
631
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]632 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
633
634 <dd>On ELF, protected visibility indicates that the symbol will be placed in
635 the dynamic symbol table, but that references within the defining module will
636 bind to the local symbol. That is, the symbol cannot be overridden by another
637 module.
638 </dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]639</dl>
640
641</div>
642
643<!-- ======================================================================= -->
644<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]645 <a name="globalvars">Global Variables</a>
646</div>
647
648<div class="doc_text">
649
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]650<p>Global variables define regions of memory allocated at compilation time
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]651instead of run-time. Global variables may optionally be initialized, may have
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]652an explicit section to be placed in, and may have an optional explicit alignment
653specified. A variable may be defined as "thread_local", which means that it
654will not be shared by threads (each thread will have a separated copy of the
655variable). A variable may be defined as a global "constant," which indicates
656that the contents of the variable will <b>never</b> be modified (enabling better
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]657optimization, allowing the global data to be placed in the read-only section of
658an executable, etc). Note that variables that need runtime initialization
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]659cannot be marked "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]660
661<p>
662LLVM explicitly allows <em>declarations</em> of global variables to be marked
663constant, even if the final definition of the global is not. This capability
664can be used to enable slightly better optimization of the program, but requires
665the language definition to guarantee that optimizations based on the
666'constantness' are valid for the translation units that do not include the
667definition.
668</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]669
670<p>As SSA values, global variables define pointer values that are in
671scope (i.e. they dominate) all basic blocks in the program. Global
672variables always define a pointer to their "content" type because they
673describe a region of memory, and all memory objects in LLVM are
674accessed through pointers.</p>
675
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]676<p>LLVM allows an explicit section to be specified for globals. If the target
677supports it, it will emit globals to the section specified.</p>
678
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]679<p>An explicit alignment may be specified for a global. If not present, or if
680the alignment is set to zero, the alignment of the global is set by the target
681to whatever it feels convenient. If an explicit alignment is specified, the
682global is forced to have at least that much alignment. All alignments must be
683a power of 2.</p>
684
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]685<p>For example, the following defines a global with an initializer, section,
686 and alignment:</p>
687
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]688<div class="doc_code">
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]689<pre>
Chris Lattner3e63a9d2007-07-13 20:01:46 +0000[diff] [blame]690@G = constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]691</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]692</div>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]693
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]694</div>
695
696
697<!-- ======================================================================= -->
698<div class="doc_subsection">
699 <a name="functionstructure">Functions</a>
700</div>
701
702<div class="doc_text">
703
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]704<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
705an optional <a href="#linkage">linkage type</a>, an optional
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]706<a href="#visibility">visibility style</a>, an optional
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]707<a href="#callingconv">calling convention</a>, a return type, an optional
708<a href="#paramattrs">parameter attribute</a> for the return type, a function
709name, a (possibly empty) argument list (each with optional
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]710<a href="#paramattrs">parameter attributes</a>), an optional section, an
711optional alignment, an opening curly brace, a list of basic blocks, and a
712closing curly brace.
713
714LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
715optional <a href="#linkage">linkage type</a>, an optional
716<a href="#visibility">visibility style</a>, an optional
717<a href="#callingconv">calling convention</a>, a return type, an optional
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]718<a href="#paramattrs">parameter attribute</a> for the return type, a function
719name, a possibly empty list of arguments, and an optional alignment.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]720
721<p>A function definition contains a list of basic blocks, forming the CFG for
722the function. Each basic block may optionally start with a label (giving the
723basic block a symbol table entry), contains a list of instructions, and ends
724with a <a href="#terminators">terminator</a> instruction (such as a branch or
725function return).</p>
726
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]727<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]728executed on entrance to the function, and it is not allowed to have predecessor
729basic blocks (i.e. there can not be any branches to the entry block of a
730function). Because the block can have no predecessors, it also cannot have any
731<a href="#i_phi">PHI nodes</a>.</p>
732
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]733<p>LLVM allows an explicit section to be specified for functions. If the target
734supports it, it will emit functions to the section specified.</p>
735
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]736<p>An explicit alignment may be specified for a function. If not present, or if
737the alignment is set to zero, the alignment of the function is set by the target
738to whatever it feels convenient. If an explicit alignment is specified, the
739function is forced to have at least that much alignment. All alignments must be
740a power of 2.</p>
741
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]742</div>
743
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]744
745<!-- ======================================================================= -->
746<div class="doc_subsection">
747 <a name="aliasstructure">Aliases</a>
748</div>
749<div class="doc_text">
750 <p>Aliases act as "second name" for the aliasee value (which can be either
Anton Korobeynikova80e1182007-04-28 13:45:00 +0000[diff] [blame]751 function or global variable or bitcast of global value). Aliases may have an
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]752 optional <a href="#linkage">linkage type</a>, and an
753 optional <a href="#visibility">visibility style</a>.</p>
754
755 <h5>Syntax:</h5>
756
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]757<div class="doc_code">
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]758<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]759@&lt;Name&gt; = [Linkage] [Visibility] alias &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]760</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]761</div>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]762
763</div>
764
765
766
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]767<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]768<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
769<div class="doc_text">
770 <p>The return type and each parameter of a function type may have a set of
771 <i>parameter attributes</i> associated with them. Parameter attributes are
772 used to communicate additional information about the result or parameters of
773 a function. Parameter attributes are considered to be part of the function
774 type so two functions types that differ only by the parameter attributes
775 are different function types.</p>
776
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]777 <p>Parameter attributes are simple keywords that follow the type specified. If
778 multiple parameter attributes are needed, they are space separated. For
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]779 example:</p>
780
781<div class="doc_code">
782<pre>
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]783%someFunc = i16 (i8 signext %someParam) zeroext
784%someFunc = i16 (i8 zeroext %someParam) zeroext
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]785</pre>
786</div>
787
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]788 <p>Note that the two function types above are unique because the parameter has
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]789 a different attribute (<tt>signext</tt> in the first one, <tt>zeroext</tt> in
790 the second). Also note that the attribute for the function result
791 (<tt>zeroext</tt>) comes immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]792
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]793 <p>Currently, only the following parameter attributes are defined:</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]794 <dl>
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]795 <dt><tt>zeroext</tt></dt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]796 <dd>This indicates that the parameter should be zero extended just before
797 a call to this function.</dd>
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]798 <dt><tt>signext</tt></dt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]799 <dd>This indicates that the parameter should be sign extended just before
800 a call to this function.</dd>
Anton Korobeynikov34d6dea2007-01-28 14:30:45 +0000[diff] [blame]801 <dt><tt>inreg</tt></dt>
802 <dd>This indicates that the parameter should be placed in register (if
Anton Korobeynikov66a8c8c2007-01-28 15:27:21 +0000[diff] [blame]803 possible) during assembling function call. Support for this attribute is
804 target-specific</dd>
Anton Korobeynikov34d6dea2007-01-28 14:30:45 +0000[diff] [blame]805 <dt><tt>sret</tt></dt>
Anton Korobeynikov66a8c8c2007-01-28 15:27:21 +0000[diff] [blame]806 <dd>This indicates that the parameter specifies the address of a structure
Reid Spencer67606122007-03-22 02:02:11 +0000[diff] [blame]807 that is the return value of the function in the source program.</dd>
Zhou Shengfebca342007-06-05 05:28:26 +0000[diff] [blame]808 <dt><tt>noalias</tt></dt>
809 <dd>This indicates that the parameter not alias any other object or any
810 other "noalias" objects during the function call.
Reid Spencer2dc52012007-03-22 02:18:56 +0000[diff] [blame]811 <dt><tt>noreturn</tt></dt>
812 <dd>This function attribute indicates that the function never returns. This
813 indicates to LLVM that every call to this function should be treated as if
814 an <tt>unreachable</tt> instruction immediately followed the call.</dd>
Reid Spencer67606122007-03-22 02:02:11 +0000[diff] [blame]815 <dt><tt>nounwind</tt></dt>
816 <dd>This function attribute indicates that the function type does not use
817 the unwind instruction and does not allow stack unwinding to propagate
818 through it.</dd>
Duncan Sands50f19f52007-07-27 19:57:41 +0000[diff] [blame]819 <dt><tt>nest</tt></dt>
820 <dd>This indicates that the parameter can be excised using the
821 <a href="#int_trampoline">trampoline intrinsics</a>.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]822 </dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]823
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]824</div>
825
826<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]827<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]828 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]829</div>
830
831<div class="doc_text">
832<p>
833Modules may contain "module-level inline asm" blocks, which corresponds to the
834GCC "file scope inline asm" blocks. These blocks are internally concatenated by
835LLVM and treated as a single unit, but may be separated in the .ll file if
836desired. The syntax is very simple:
837</p>
838
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]839<div class="doc_code">
840<pre>
841module asm "inline asm code goes here"
842module asm "more can go here"
843</pre>
844</div>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]845
846<p>The strings can contain any character by escaping non-printable characters.
847 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
848 for the number.
849</p>
850
851<p>
852 The inline asm code is simply printed to the machine code .s file when
853 assembly code is generated.
854</p>
855</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]856
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]857<!-- ======================================================================= -->
858<div class="doc_subsection">
859 <a name="datalayout">Data Layout</a>
860</div>
861
862<div class="doc_text">
863<p>A module may specify a target specific data layout string that specifies how
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]864data is to be laid out in memory. The syntax for the data layout is simply:</p>
865<pre> target datalayout = "<i>layout specification</i>"</pre>
866<p>The <i>layout specification</i> consists of a list of specifications
867separated by the minus sign character ('-'). Each specification starts with a
868letter and may include other information after the letter to define some
869aspect of the data layout. The specifications accepted are as follows: </p>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]870<dl>
871 <dt><tt>E</tt></dt>
872 <dd>Specifies that the target lays out data in big-endian form. That is, the
873 bits with the most significance have the lowest address location.</dd>
874 <dt><tt>e</tt></dt>
875 <dd>Specifies that hte target lays out data in little-endian form. That is,
876 the bits with the least significance have the lowest address location.</dd>
877 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
878 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
879 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
880 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
881 too.</dd>
882 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
883 <dd>This specifies the alignment for an integer type of a given bit
884 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
885 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
886 <dd>This specifies the alignment for a vector type of a given bit
887 <i>size</i>.</dd>
888 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
889 <dd>This specifies the alignment for a floating point type of a given bit
890 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
891 (double).</dd>
892 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
893 <dd>This specifies the alignment for an aggregate type of a given bit
894 <i>size</i>.</dd>
895</dl>
896<p>When constructing the data layout for a given target, LLVM starts with a
897default set of specifications which are then (possibly) overriden by the
898specifications in the <tt>datalayout</tt> keyword. The default specifications
899are given in this list:</p>
900<ul>
901 <li><tt>E</tt> - big endian</li>
902 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
903 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
904 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
905 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
906 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
907 <li><tt>i64:32:64</tt> - i64 has abi alignment of 32-bits but preferred
908 alignment of 64-bits</li>
909 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
910 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
911 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
912 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
913 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
914</ul>
915<p>When llvm is determining the alignment for a given type, it uses the
916following rules:
917<ol>
918 <li>If the type sought is an exact match for one of the specifications, that
919 specification is used.</li>
920 <li>If no match is found, and the type sought is an integer type, then the
921 smallest integer type that is larger than the bitwidth of the sought type is
922 used. If none of the specifications are larger than the bitwidth then the the
923 largest integer type is used. For example, given the default specifications
924 above, the i7 type will use the alignment of i8 (next largest) while both
925 i65 and i256 will use the alignment of i64 (largest specified).</li>
926 <li>If no match is found, and the type sought is a vector type, then the
927 largest vector type that is smaller than the sought vector type will be used
928 as a fall back. This happens because <128 x double> can be implemented in
929 terms of 64 <2 x double>, for example.</li>
930</ol>
931</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]932
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]933<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]934<div class="doc_section"> <a name="typesystem">Type System</a> </div>
935<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]936
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]937<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]938
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]939<p>The LLVM type system is one of the most important features of the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]940intermediate representation. Being typed enables a number of
941optimizations to be performed on the IR directly, without having to do
942extra analyses on the side before the transformation. A strong type
943system makes it easier to read the generated code and enables novel
944analyses and transformations that are not feasible to perform on normal
945three address code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]946
947</div>
948
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]949<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]950<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]951<div class="doc_text">
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]952<p>The primitive types are the fundamental building blocks of the LLVM
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]953system. The current set of primitive types is as follows:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]954
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]955<table class="layout">
956 <tr class="layout">
957 <td class="left">
958 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]959 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]960 <tr><th>Type</th><th>Description</th></tr>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]961 <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]962 <tr><td><tt>label</tt></td><td>Branch destination</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]963 </tbody>
964 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]965 </td>
966 <td class="right">
967 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]968 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]969 <tr><th>Type</th><th>Description</th></tr>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]970 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]971 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]972 </tbody>
973 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]974 </td>
975 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]976</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]977</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]978
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]979<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]980<div class="doc_subsubsection"> <a name="t_classifications">Type
981Classifications</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]982<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]983<p>These different primitive types fall into a few useful
984classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]985
986<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]987 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]988 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]989 <tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]990 <td><a name="t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]991 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]992 </tr>
993 <tr>
994 <td><a name="t_floating">floating point</a></td>
995 <td><tt>float, double</tt></td>
996 </tr>
997 <tr>
998 <td><a name="t_firstclass">first class</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]999 <td><tt>i1, ..., float, double, <br/>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1000 <a href="#t_pointer">pointer</a>,<a href="#t_vector">vector</a></tt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1001 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1002 </tr>
1003 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1004</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1005
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1006<p>The <a href="#t_firstclass">first class</a> types are perhaps the
1007most important. Values of these types are the only ones which can be
1008produced by instructions, passed as arguments, or used as operands to
1009instructions. This means that all structures and arrays must be
1010manipulated either by pointer or by component.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1011</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1012
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1013<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1014<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1015
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1016<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1017
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1018<p>The real power in LLVM comes from the derived types in the system.
1019This is what allows a programmer to represent arrays, functions,
1020pointers, and other useful types. Note that these derived types may be
1021recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1022
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1023</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1024
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1025<!-- _______________________________________________________________________ -->
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1026<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1027
1028<div class="doc_text">
1029
1030<h5>Overview:</h5>
1031<p>The integer type is a very simple derived type that simply specifies an
1032arbitrary bit width for the integer type desired. Any bit width from 1 bit to
10332^23-1 (about 8 million) can be specified.</p>
1034
1035<h5>Syntax:</h5>
1036
1037<pre>
1038 iN
1039</pre>
1040
1041<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1042value.</p>
1043
1044<h5>Examples:</h5>
1045<table class="layout">
1046 <tr class="layout">
1047 <td class="left">
1048 <tt>i1</tt><br/>
1049 <tt>i4</tt><br/>
1050 <tt>i8</tt><br/>
1051 <tt>i16</tt><br/>
1052 <tt>i32</tt><br/>
1053 <tt>i42</tt><br/>
1054 <tt>i64</tt><br/>
1055 <tt>i1942652</tt><br/>
1056 </td>
1057 <td class="left">
1058 A boolean integer of 1 bit<br/>
1059 A nibble sized integer of 4 bits.<br/>
1060 A byte sized integer of 8 bits.<br/>
1061 A half word sized integer of 16 bits.<br/>
1062 A word sized integer of 32 bits.<br/>
1063 An integer whose bit width is the answer. <br/>
1064 A double word sized integer of 64 bits.<br/>
1065 A really big integer of over 1 million bits.<br/>
1066 </td>
1067 </tr>
1068</table>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1069</div>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1070
1071<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1072<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1073
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1074<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1075
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1076<h5>Overview:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1077
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1078<p>The array type is a very simple derived type that arranges elements
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1079sequentially in memory. The array type requires a size (number of
1080elements) and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1081
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1082<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1083
1084<pre>
1085 [&lt;# elements&gt; x &lt;elementtype&gt;]
1086</pre>
1087
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1088<p>The number of elements is a constant integer value; elementtype may
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1089be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1090
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1091<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1092<table class="layout">
1093 <tr class="layout">
1094 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1095 <tt>[40 x i32 ]</tt><br/>
1096 <tt>[41 x i32 ]</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1097 <tt>[40 x i8]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1098 </td>
1099 <td class="left">
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1100 Array of 40 32-bit integer values.<br/>
1101 Array of 41 32-bit integer values.<br/>
1102 Array of 40 8-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1103 </td>
1104 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1105</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1106<p>Here are some examples of multidimensional arrays:</p>
1107<table class="layout">
1108 <tr class="layout">
1109 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1110 <tt>[3 x [4 x i32]]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1111 <tt>[12 x [10 x float]]</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1112 <tt>[2 x [3 x [4 x i16]]]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1113 </td>
1114 <td class="left">
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1115 3x4 array of 32-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1116 12x10 array of single precision floating point values.<br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1117 2x3x4 array of 16-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1118 </td>
1119 </tr>
1120</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1121
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1122<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1123length array. Normally, accesses past the end of an array are undefined in
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1124LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1125As a special case, however, zero length arrays are recognized to be variable
1126length. This allows implementation of 'pascal style arrays' with the LLVM
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1127type "{ i32, [0 x float]}", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1128
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1129</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1130
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1131<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1132<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1133<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1134<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1135<p>The function type can be thought of as a function signature. It
1136consists of a return type and a list of formal parameter types.
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]1137Function types are usually used to build virtual function tables
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1138(which are structures of pointers to functions), for indirect function
1139calls, and when defining a function.</p>
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]1140<p>
1141The return type of a function type cannot be an aggregate type.
1142</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1143<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1144<pre> &lt;returntype&gt; (&lt;parameter list&gt;)<br></pre>
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1145<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]1146specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1147which indicates that the function takes a variable number of arguments.
1148Variable argument functions can access their arguments with the <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1149 href="#int_varargs">variable argument handling intrinsic</a> functions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1150<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1151<table class="layout">
1152 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1153 <td class="left"><tt>i32 (i32)</tt></td>
1154 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1155 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1156 </tr><tr class="layout">
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]1157 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1158 </tt></td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1159 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1160 an <tt>i16</tt> that should be sign extended and a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1161 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1162 <tt>float</tt>.
1163 </td>
1164 </tr><tr class="layout">
1165 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1166 <td class="left">A vararg function that takes at least one
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1167 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1168 which returns an integer. This is the signature for <tt>printf</tt> in
1169 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1170 </td>
1171 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1172</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1173
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1174</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1175<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1176<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1177<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1178<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1179<p>The structure type is used to represent a collection of data members
1180together in memory. The packing of the field types is defined to match
1181the ABI of the underlying processor. The elements of a structure may
1182be any type that has a size.</p>
1183<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1184and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1185field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1186instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1187<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1188<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1189<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1190<table class="layout">
1191 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1192 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1193 <td class="left">A triple of three <tt>i32</tt> values</td>
1194 </tr><tr class="layout">
1195 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1196 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1197 second element is a <a href="#t_pointer">pointer</a> to a
1198 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1199 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1200 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1201</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1202</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1203
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1204<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1205<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1206</div>
1207<div class="doc_text">
1208<h5>Overview:</h5>
1209<p>The packed structure type is used to represent a collection of data members
1210together in memory. There is no padding between fields. Further, the alignment
1211of a packed structure is 1 byte. The elements of a packed structure may
1212be any type that has a size.</p>
1213<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1214and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1215field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1216instruction.</p>
1217<h5>Syntax:</h5>
1218<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1219<h5>Examples:</h5>
1220<table class="layout">
1221 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1222 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1223 <td class="left">A triple of three <tt>i32</tt> values</td>
1224 </tr><tr class="layout">
1225 <td class="left"><tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}&nbsp;&gt;</tt></td>
1226 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1227 second element is a <a href="#t_pointer">pointer</a> to a
1228 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1229 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1230 </tr>
1231</table>
1232</div>
1233
1234<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1235<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1236<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1237<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1238<p>As in many languages, the pointer type represents a pointer or
1239reference to another object, which must live in memory.</p>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1240<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1241<pre> &lt;type&gt; *<br></pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1242<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1243<table class="layout">
1244 <tr class="layout">
1245 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1246 <tt>[4x i32]*</tt><br/>
1247 <tt>i32 (i32 *) *</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1248 </td>
1249 <td class="left">
1250 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]1251 four <tt>i32</tt> values<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1252 A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1253 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
1254 <tt>i32</tt>.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1255 </td>
1256 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1257</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1258</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1259
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1260<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1261<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1262<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1263
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1264<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1265
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1266<p>A vector type is a simple derived type that represents a vector
1267of elements. Vector types are used when multiple primitive data
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1268are operated in parallel using a single instruction (SIMD).
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1269A vector type requires a size (number of
Chris Lattnerb8d172f2005-11-10 01:44:22 +0000[diff] [blame]1270elements) and an underlying primitive data type. Vectors must have a power
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1271of two length (1, 2, 4, 8, 16 ...). Vector types are
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1272considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1273
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1274<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1275
1276<pre>
1277 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1278</pre>
1279
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1280<p>The number of elements is a constant integer value; elementtype may
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]1281be any integer or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1282
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1283<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1284
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1285<table class="layout">
1286 <tr class="layout">
1287 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1288 <tt>&lt;4 x i32&gt;</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1289 <tt>&lt;8 x float&gt;</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1290 <tt>&lt;2 x i64&gt;</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1291 </td>
1292 <td class="left">
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1293 Vector of 4 32-bit integer values.<br/>
1294 Vector of 8 floating-point values.<br/>
1295 Vector of 2 64-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1296 </td>
1297 </tr>
1298</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1299</div>
1300
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1301<!-- _______________________________________________________________________ -->
1302<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1303<div class="doc_text">
1304
1305<h5>Overview:</h5>
1306
1307<p>Opaque types are used to represent unknown types in the system. This
1308corresponds (for example) to the C notion of a foward declared structure type.
1309In LLVM, opaque types can eventually be resolved to any type (not just a
1310structure type).</p>
1311
1312<h5>Syntax:</h5>
1313
1314<pre>
1315 opaque
1316</pre>
1317
1318<h5>Examples:</h5>
1319
1320<table class="layout">
1321 <tr class="layout">
1322 <td class="left">
1323 <tt>opaque</tt>
1324 </td>
1325 <td class="left">
1326 An opaque type.<br/>
1327 </td>
1328 </tr>
1329</table>
1330</div>
1331
1332
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1333<!-- *********************************************************************** -->
1334<div class="doc_section"> <a name="constants">Constants</a> </div>
1335<!-- *********************************************************************** -->
1336
1337<div class="doc_text">
1338
1339<p>LLVM has several different basic types of constants. This section describes
1340them all and their syntax.</p>
1341
1342</div>
1343
1344<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1345<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1346
1347<div class="doc_text">
1348
1349<dl>
1350 <dt><b>Boolean constants</b></dt>
1351
1352 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1353 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1354 </dd>
1355
1356 <dt><b>Integer constants</b></dt>
1357
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1358 <dd>Standard integers (such as '4') are constants of the <a
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1359 href="#t_integer">integer</a> type. Negative numbers may be used with
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1360 integer types.
1361 </dd>
1362
1363 <dt><b>Floating point constants</b></dt>
1364
1365 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1366 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1367 notation (see below). Floating point constants must have a <a
1368 href="#t_floating">floating point</a> type. </dd>
1369
1370 <dt><b>Null pointer constants</b></dt>
1371
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1372 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1373 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1374
1375</dl>
1376
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1377<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1378of floating point constants. For example, the form '<tt>double
13790x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
13804.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1381(and the only time that they are generated by the disassembler) is when a
1382floating point constant must be emitted but it cannot be represented as a
1383decimal floating point number. For example, NaN's, infinities, and other
1384special values are represented in their IEEE hexadecimal format so that
1385assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1386
1387</div>
1388
1389<!-- ======================================================================= -->
1390<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1391</div>
1392
1393<div class="doc_text">
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1394<p>Aggregate constants arise from aggregation of simple constants
1395and smaller aggregate constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1396
1397<dl>
1398 <dt><b>Structure constants</b></dt>
1399
1400 <dd>Structure constants are represented with notation similar to structure
1401 type definitions (a comma separated list of elements, surrounded by braces
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1402 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* %G }</tt>",
Chris Lattner3e63a9d2007-07-13 20:01:46 +0000[diff] [blame]1403 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]1404 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1405 types of elements must match those specified by the type.
1406 </dd>
1407
1408 <dt><b>Array constants</b></dt>
1409
1410 <dd>Array constants are represented with notation similar to array type
1411 definitions (a comma separated list of elements, surrounded by square brackets
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1412 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1413 constants must have <a href="#t_array">array type</a>, and the number and
1414 types of elements must match those specified by the type.
1415 </dd>
1416
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1417 <dt><b>Vector constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1418
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1419 <dd>Vector constants are represented with notation similar to vector type
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1420 definitions (a comma separated list of elements, surrounded by
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1421 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]1422 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1423 href="#t_vector">vector type</a>, and the number and types of elements must
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1424 match those specified by the type.
1425 </dd>
1426
1427 <dt><b>Zero initialization</b></dt>
1428
1429 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1430 value to zero of <em>any</em> type, including scalar and aggregate types.
1431 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]1432 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1433 initializers.
1434 </dd>
1435</dl>
1436
1437</div>
1438
1439<!-- ======================================================================= -->
1440<div class="doc_subsection">
1441 <a name="globalconstants">Global Variable and Function Addresses</a>
1442</div>
1443
1444<div class="doc_text">
1445
1446<p>The addresses of <a href="#globalvars">global variables</a> and <a
1447href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1448constants. These constants are explicitly referenced when the <a
1449href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1450href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1451file:</p>
1452
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1453<div class="doc_code">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1454<pre>
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]1455@X = global i32 17
1456@Y = global i32 42
1457@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1458</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1459</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1460
1461</div>
1462
1463<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1464<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1465<div class="doc_text">
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1466 <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]1467 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1468 a constant is permitted.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1469
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1470 <p>Undefined values indicate to the compiler that the program is well defined
1471 no matter what value is used, giving the compiler more freedom to optimize.
1472 </p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1473</div>
1474
1475<!-- ======================================================================= -->
1476<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1477</div>
1478
1479<div class="doc_text">
1480
1481<p>Constant expressions are used to allow expressions involving other constants
1482to be used as constants. Constant expressions may be of any <a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1483href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1484that does not have side effects (e.g. load and call are not supported). The
1485following is the syntax for constant expressions:</p>
1486
1487<dl>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1488 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1489 <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]1490 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1491
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1492 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1493 <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]1494 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]1495
1496 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1497 <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]1498 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]1499
1500 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1501 <dd>Truncate a floating point constant to another floating point type. The
1502 size of CST must be larger than the size of TYPE. Both types must be
1503 floating point.</dd>
1504
1505 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1506 <dd>Floating point extend a constant to another type. The size of CST must be
1507 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1508
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]1509 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1510 <dd>Convert a floating point constant to the corresponding unsigned integer
1511 constant. TYPE must be an integer type. CST must be floating point. If the
1512 value won't fit in the integer type, the results are undefined.</dd>
1513
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1514 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1515 <dd>Convert a floating point constant to the corresponding signed integer
1516 constant. TYPE must be an integer type. CST must be floating point. If the
1517 value won't fit in the integer type, the results are undefined.</dd>
1518
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1519 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1520 <dd>Convert an unsigned integer constant to the corresponding floating point
1521 constant. TYPE must be floating point. CST must be of integer type. If the
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]1522 value won't fit in the floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1523
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1524 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1525 <dd>Convert a signed integer constant to the corresponding floating point
1526 constant. TYPE must be floating point. CST must be of integer type. If the
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]1527 value won't fit in the floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1528
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]1529 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1530 <dd>Convert a pointer typed constant to the corresponding integer constant
1531 TYPE must be an integer type. CST must be of pointer type. The CST value is
1532 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1533
1534 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1535 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1536 pointer type. CST must be of integer type. The CST value is zero extended,
1537 truncated, or unchanged to make it fit in a pointer size. This one is
1538 <i>really</i> dangerous!</dd>
1539
1540 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1541 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1542 identical (same number of bits). The conversion is done as if the CST value
1543 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]1544 with this operator, just the type. This can be used for conversion of
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1545 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]1546 pointers it is only valid to cast to another pointer type.
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1547 </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1548
1549 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1550
1551 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1552 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1553 instruction, the index list may have zero or more indexes, which are required
1554 to make sense for the type of "CSTPTR".</dd>
1555
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1556 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1557
1558 <dd>Perform the <a href="#i_select">select operation</a> on
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1559 constants.</dd>
1560
1561 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1562 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1563
1564 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1565 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1566
1567 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1568
1569 <dd>Perform the <a href="#i_extractelement">extractelement
1570 operation</a> on constants.
1571
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1572 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1573
1574 <dd>Perform the <a href="#i_insertelement">insertelement
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1575 operation</a> on constants.</dd>
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1576
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1577
1578 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1579
1580 <dd>Perform the <a href="#i_shufflevector">shufflevector
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1581 operation</a> on constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1582
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1583 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1584
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1585 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1586 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1587 binary</a> operations. The constraints on operands are the same as those for
1588 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1589 values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1590</dl>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1591</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]1592
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1593<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1594<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1595<!-- *********************************************************************** -->
1596
1597<!-- ======================================================================= -->
1598<div class="doc_subsection">
1599<a name="inlineasm">Inline Assembler Expressions</a>
1600</div>
1601
1602<div class="doc_text">
1603
1604<p>
1605LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1606Module-Level Inline Assembly</a>) through the use of a special value. This
1607value represents the inline assembler as a string (containing the instructions
1608to emit), a list of operand constraints (stored as a string), and a flag that
1609indicates whether or not the inline asm expression has side effects. An example
1610inline assembler expression is:
1611</p>
1612
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1613<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1614<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1615i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1616</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1617</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1618
1619<p>
1620Inline assembler expressions may <b>only</b> be used as the callee operand of
1621a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1622</p>
1623
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1624<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1625<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1626%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]1627</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1628</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1629
1630<p>
1631Inline asms with side effects not visible in the constraint list must be marked
1632as having side effects. This is done through the use of the
1633'<tt>sideeffect</tt>' keyword, like so:
1634</p>
1635
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1636<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1637<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1638call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1639</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1640</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1641
1642<p>TODO: The format of the asm and constraints string still need to be
1643documented here. Constraints on what can be done (e.g. duplication, moving, etc
1644need to be documented).
1645</p>
1646
1647</div>
1648
1649<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1650<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1651<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1652
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1653<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1654
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1655<p>The LLVM instruction set consists of several different
1656classifications of instructions: <a href="#terminators">terminator
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1657instructions</a>, <a href="#binaryops">binary instructions</a>,
1658<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1659 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1660instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1661
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1662</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1663
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1664<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1665<div class="doc_subsection"> <a name="terminators">Terminator
1666Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1667
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1668<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1669
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1670<p>As mentioned <a href="#functionstructure">previously</a>, every
1671basic block in a program ends with a "Terminator" instruction, which
1672indicates which block should be executed after the current block is
1673finished. These terminator instructions typically yield a '<tt>void</tt>'
1674value: they produce control flow, not values (the one exception being
1675the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1676<p>There are six different terminator instructions: the '<a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1677 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1678instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1679the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1680 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1681 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1682
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1683</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1684
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1685<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1686<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1687Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1688<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1689<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1690<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]1691 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1692</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1693<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1694<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1695value) from a function back to the caller.</p>
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]1696<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1697returns a value and then causes control flow, and one that just causes
1698control flow to occur.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1699<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1700<p>The '<tt>ret</tt>' instruction may return any '<a
1701 href="#t_firstclass">first class</a>' type. Notice that a function is
1702not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
1703instruction inside of the function that returns a value that does not
1704match the return type of the function.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1705<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1706<p>When the '<tt>ret</tt>' instruction is executed, control flow
1707returns back to the calling function's context. If the caller is a "<a
John Criswellfa081872004-06-25 15:16:57 +0000[diff] [blame]1708 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1709the instruction after the call. If the caller was an "<a
1710 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1711at the beginning of the "normal" destination block. If the instruction
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1712returns a value, that value shall set the call or invoke instruction's
1713return value.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1714<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1715<pre> ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1716 ret void <i>; Return from a void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1717</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1718</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1719<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1720<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1721<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1722<h5>Syntax:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1723<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]1724</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1725<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1726<p>The '<tt>br</tt>' instruction is used to cause control flow to
1727transfer to a different basic block in the current function. There are
1728two forms of this instruction, corresponding to a conditional branch
1729and an unconditional branch.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1730<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1731<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1732single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1733unconditional form of the '<tt>br</tt>' instruction takes a single
1734'<tt>label</tt>' value as a target.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1735<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1736<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1737argument is evaluated. If the value is <tt>true</tt>, control flows
1738to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1739control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1740<h5>Example:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1741<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]1742 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]1743</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1744<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1745<div class="doc_subsubsection">
1746 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1747</div>
1748
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1749<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1750<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1751
1752<pre>
1753 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1754</pre>
1755
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1756<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1757
1758<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1759several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1760instruction, allowing a branch to occur to one of many possible
1761destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1762
1763
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1764<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1765
1766<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1767comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1768an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1769table is not allowed to contain duplicate constant entries.</p>
1770
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1771<h5>Semantics:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1772
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1773<p>The <tt>switch</tt> instruction specifies a table of values and
1774destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1775table is searched for the given value. If the value is found, control flow is
1776transfered to the corresponding destination; otherwise, control flow is
1777transfered to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1778
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1779<h5>Implementation:</h5>
1780
1781<p>Depending on properties of the target machine and the particular
1782<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1783ways. For example, it could be generated as a series of chained conditional
1784branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1785
1786<h5>Example:</h5>
1787
1788<pre>
1789 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1790 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1791 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1792
1793 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1794 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1795
1796 <i>; Implement a jump table:</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1797 switch i32 %val, label %otherwise [ i32 0, label %onzero
1798 i32 1, label %onone
1799 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1800</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1801</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1802
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1803<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1804<div class="doc_subsubsection">
1805 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1806</div>
1807
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1808<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1809
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1810<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1811
1812<pre>
1813 &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]1814 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1815</pre>
1816
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1817<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1818
1819<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1820function, with the possibility of control flow transfer to either the
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1821'<tt>normal</tt>' label or the
1822'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1823"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1824"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1825href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
1826continued at the dynamically nearest "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1827
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1828<h5>Arguments:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1829
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1830<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1831
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1832<ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1833 <li>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]1834 The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1835 convention</a> the call should use. If none is specified, the call defaults
1836 to using C calling conventions.
1837 </li>
1838 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1839 function value being invoked. In most cases, this is a direct function
1840 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1841 an arbitrary pointer to function value.
1842 </li>
1843
1844 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1845 function to be invoked. </li>
1846
1847 <li>'<tt>function args</tt>': argument list whose types match the function
1848 signature argument types. If the function signature indicates the function
1849 accepts a variable number of arguments, the extra arguments can be
1850 specified. </li>
1851
1852 <li>'<tt>normal label</tt>': the label reached when the called function
1853 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1854
1855 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1856 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1857
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1858</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1859
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1860<h5>Semantics:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1861
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1862<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1863href="#i_call">call</a></tt>' instruction in most regards. The primary
1864difference is that it establishes an association with a label, which is used by
1865the runtime library to unwind the stack.</p>
1866
1867<p>This instruction is used in languages with destructors to ensure that proper
1868cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1869exception. Additionally, this is important for implementation of
1870'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1871
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1872<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1873<pre>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1874 %retval = invoke i32 %Test(i32 15) to label %Continue
1875 unwind label %TestCleanup <i>; {i32}:retval set</i>
1876 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Test(i32 15) to label %Continue
1877 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1878</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1879</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1880
1881
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1882<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1883
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1884<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1885Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1886
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1887<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1888
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1889<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1890<pre>
1891 unwind
1892</pre>
1893
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1894<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1895
1896<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
1897at the first callee in the dynamic call stack which used an <a
1898href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
1899primarily used to implement exception handling.</p>
1900
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1901<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1902
1903<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
1904immediately halt. The dynamic call stack is then searched for the first <a
1905href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
1906execution continues at the "exceptional" destination block specified by the
1907<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
1908dynamic call chain, undefined behavior results.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1909</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1910
1911<!-- _______________________________________________________________________ -->
1912
1913<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
1914Instruction</a> </div>
1915
1916<div class="doc_text">
1917
1918<h5>Syntax:</h5>
1919<pre>
1920 unreachable
1921</pre>
1922
1923<h5>Overview:</h5>
1924
1925<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
1926instruction is used to inform the optimizer that a particular portion of the
1927code is not reachable. This can be used to indicate that the code after a
1928no-return function cannot be reached, and other facts.</p>
1929
1930<h5>Semantics:</h5>
1931
1932<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
1933</div>
1934
1935
1936
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1937<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1938<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1939<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1940<p>Binary operators are used to do most of the computation in a
1941program. They require two operands, execute an operation on them, and
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1942produce a single value. The operands might represent
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1943multiple 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]1944The result value of a binary operator is not
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1945necessarily the same type as its operands.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1946<p>There are several different binary operators:</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1947</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1948<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1949<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
1950Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1951<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1952<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1953<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]1954</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1955<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1956<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1957<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1958<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1959 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1960 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]1961Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1962<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1963<p>The value produced is the integer or floating point sum of the two
1964operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1965<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1966<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]1967</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1968</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1969<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1970<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
1971Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1972<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1973<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1974<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]1975</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1976<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1977<p>The '<tt>sub</tt>' instruction returns the difference of its two
1978operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1979<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
1980instruction present in most other intermediate representations.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1981<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1982<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1983 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1984values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1985This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1986Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1987<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1988<p>The value produced is the integer or floating point difference of
1989the two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1990<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]1991<pre>
1992 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1993 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1994</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1995</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1996<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1997<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
1998Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1999<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2000<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2001<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]2002</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2003<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2004<p>The '<tt>mul</tt>' instruction returns the product of its two
2005operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2006<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2007<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2008 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2009values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2010This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2011Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2012<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2013<p>The value produced is the integer or floating point product of the
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2014two operands.</p>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]2015<p>Because the operands are the same width, the result of an integer
2016multiplication is the same whether the operands should be deemed unsigned or
2017signed.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2018<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2019<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]2020</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2021</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2022<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2023<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2024</a></div>
2025<div class="doc_text">
2026<h5>Syntax:</h5>
2027<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2028</pre>
2029<h5>Overview:</h5>
2030<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2031operands.</p>
2032<h5>Arguments:</h5>
2033<p>The two arguments to the '<tt>udiv</tt>' instruction must be
2034<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2035types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2036of the values in which case the elements must be integers.</p>
2037<h5>Semantics:</h5>
2038<p>The value produced is the unsigned integer quotient of the two operands. This
2039instruction always performs an unsigned division operation, regardless of
2040whether the arguments are unsigned or not.</p>
2041<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2042<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]2043</pre>
2044</div>
2045<!-- _______________________________________________________________________ -->
2046<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2047</a> </div>
2048<div class="doc_text">
2049<h5>Syntax:</h5>
2050<pre> &lt;result&gt; = sdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2051</pre>
2052<h5>Overview:</h5>
2053<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2054operands.</p>
2055<h5>Arguments:</h5>
2056<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2057<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2058types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2059of the values in which case the elements must be integers.</p>
2060<h5>Semantics:</h5>
2061<p>The value produced is the signed integer quotient of the two operands. This
2062instruction always performs a signed division operation, regardless of whether
2063the arguments are signed or not.</p>
2064<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2065<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]2066</pre>
2067</div>
2068<!-- _______________________________________________________________________ -->
2069<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2070Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2071<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2072<h5>Syntax:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2073<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]2074</pre>
2075<h5>Overview:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2076<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2077operands.</p>
2078<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2079<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2080<a href="#t_floating">floating point</a> values. Both arguments must have
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2081identical types. This instruction can also take <a href="#t_vector">vector</a>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2082versions of floating point values.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2083<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2084<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2085<h5>Example:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2086<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]2087</pre>
2088</div>
2089<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2090<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2091</div>
2092<div class="doc_text">
2093<h5>Syntax:</h5>
2094<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2095</pre>
2096<h5>Overview:</h5>
2097<p>The '<tt>urem</tt>' instruction returns the remainder from the
2098unsigned division of its two arguments.</p>
2099<h5>Arguments:</h5>
2100<p>The two arguments to the '<tt>urem</tt>' instruction must be
2101<a href="#t_integer">integer</a> values. Both arguments must have identical
2102types.</p>
2103<h5>Semantics:</h5>
2104<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
2105This instruction always performs an unsigned division to get the remainder,
2106regardless of whether the arguments are unsigned or not.</p>
2107<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2108<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]2109</pre>
2110
2111</div>
2112<!-- _______________________________________________________________________ -->
2113<div class="doc_subsubsection"> <a name="i_srem">'<tt>srem</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2114Instruction</a> </div>
2115<div class="doc_text">
2116<h5>Syntax:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2117<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]2118</pre>
2119<h5>Overview:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2120<p>The '<tt>srem</tt>' instruction returns the remainder from the
2121signed division of its two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2122<h5>Arguments:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2123<p>The two arguments to the '<tt>srem</tt>' instruction must be
2124<a href="#t_integer">integer</a> values. Both arguments must have identical
2125types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2126<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2127<p>This instruction returns the <i>remainder</i> of a division (where the result
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2128has the same sign as the dividend, <tt>var1</tt>), not the <i>modulo</i>
2129operator (where the result has the same sign as the divisor, <tt>var2</tt>) of
2130a value. For more information about the difference, see <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2131 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2132Math Forum</a>. For a table of how this is implemented in various languages,
Reid Spencer64f5c6c2007-03-24 22:40:44 +0000[diff] [blame]2133please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2134Wikipedia: modulo operation</a>.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2135<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2136<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]2137</pre>
2138
2139</div>
2140<!-- _______________________________________________________________________ -->
2141<div class="doc_subsubsection"> <a name="i_frem">'<tt>frem</tt>'
2142Instruction</a> </div>
2143<div class="doc_text">
2144<h5>Syntax:</h5>
2145<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2146</pre>
2147<h5>Overview:</h5>
2148<p>The '<tt>frem</tt>' instruction returns the remainder from the
2149division of its two operands.</p>
2150<h5>Arguments:</h5>
2151<p>The two arguments to the '<tt>frem</tt>' instruction must be
2152<a href="#t_floating">floating point</a> values. Both arguments must have
2153identical types.</p>
2154<h5>Semantics:</h5>
2155<p>This instruction returns the <i>remainder</i> of a division.</p>
2156<h5>Example:</h5>
2157<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]2158</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2159</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]2160
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]2161<!-- ======================================================================= -->
2162<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2163Operations</a> </div>
2164<div class="doc_text">
2165<p>Bitwise binary operators are used to do various forms of
2166bit-twiddling in a program. They are generally very efficient
2167instructions and can commonly be strength reduced from other
2168instructions. They require two operands, execute an operation on them,
2169and produce a single value. The resulting value of the bitwise binary
2170operators is always the same type as its first operand.</p>
2171</div>
2172
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2173<!-- _______________________________________________________________________ -->
2174<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2175Instruction</a> </div>
2176<div class="doc_text">
2177<h5>Syntax:</h5>
2178<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2179</pre>
2180<h5>Overview:</h5>
2181<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2182the left a specified number of bits.</p>
2183<h5>Arguments:</h5>
2184<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
2185 href="#t_integer">integer</a> type.</p>
2186<h5>Semantics:</h5>
2187<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>.</p>
2188<h5>Example:</h5><pre>
2189 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2190 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2191 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
2192</pre>
2193</div>
2194<!-- _______________________________________________________________________ -->
2195<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2196Instruction</a> </div>
2197<div class="doc_text">
2198<h5>Syntax:</h5>
2199<pre> &lt;result&gt; = lshr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2200</pre>
2201
2202<h5>Overview:</h5>
2203<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2204operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2205
2206<h5>Arguments:</h5>
2207<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
2208<a href="#t_integer">integer</a> type.</p>
2209
2210<h5>Semantics:</h5>
2211<p>This instruction always performs a logical shift right operation. The most
2212significant bits of the result will be filled with zero bits after the
2213shift.</p>
2214
2215<h5>Example:</h5>
2216<pre>
2217 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2218 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2219 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2220 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
2221</pre>
2222</div>
2223
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]2224<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2225<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2226Instruction</a> </div>
2227<div class="doc_text">
2228
2229<h5>Syntax:</h5>
2230<pre> &lt;result&gt; = ashr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2231</pre>
2232
2233<h5>Overview:</h5>
2234<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2235operand shifted to the right a specified number of bits with sign extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2236
2237<h5>Arguments:</h5>
2238<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
2239<a href="#t_integer">integer</a> type.</p>
2240
2241<h5>Semantics:</h5>
2242<p>This instruction always performs an arithmetic shift right operation,
2243The most significant bits of the result will be filled with the sign bit
2244of <tt>var1</tt>.</p>
2245
2246<h5>Example:</h5>
2247<pre>
2248 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2249 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2250 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2251 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
2252</pre>
2253</div>
2254
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2255<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2256<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2257Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2258<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2259<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2260<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]2261</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2262<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2263<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2264its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2265<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2266<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2267 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2268identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2269<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2270<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2271<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2272<div style="align: center">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2273<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2274 <tbody>
2275 <tr>
2276 <td>In0</td>
2277 <td>In1</td>
2278 <td>Out</td>
2279 </tr>
2280 <tr>
2281 <td>0</td>
2282 <td>0</td>
2283 <td>0</td>
2284 </tr>
2285 <tr>
2286 <td>0</td>
2287 <td>1</td>
2288 <td>0</td>
2289 </tr>
2290 <tr>
2291 <td>1</td>
2292 <td>0</td>
2293 <td>0</td>
2294 </tr>
2295 <tr>
2296 <td>1</td>
2297 <td>1</td>
2298 <td>1</td>
2299 </tr>
2300 </tbody>
2301</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2302</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2303<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2304<pre> &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
2305 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2306 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2307</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2308</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2309<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2310<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2311<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2312<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2313<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]2314</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2315<h5>Overview:</h5>
2316<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2317or of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2318<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2319<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2320 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2321identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2322<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2323<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2324<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2325<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2326<table border="1" cellspacing="0" cellpadding="4">
2327 <tbody>
2328 <tr>
2329 <td>In0</td>
2330 <td>In1</td>
2331 <td>Out</td>
2332 </tr>
2333 <tr>
2334 <td>0</td>
2335 <td>0</td>
2336 <td>0</td>
2337 </tr>
2338 <tr>
2339 <td>0</td>
2340 <td>1</td>
2341 <td>1</td>
2342 </tr>
2343 <tr>
2344 <td>1</td>
2345 <td>0</td>
2346 <td>1</td>
2347 </tr>
2348 <tr>
2349 <td>1</td>
2350 <td>1</td>
2351 <td>1</td>
2352 </tr>
2353 </tbody>
2354</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2355</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2356<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2357<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2358 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2359 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2360</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2361</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2362<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2363<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2364Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2365<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2366<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2367<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]2368</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2369<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2370<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2371or of its two operands. The <tt>xor</tt> is used to implement the
2372"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2373<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2374<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2375 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2376identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2377<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2378<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2379<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2380<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2381<table border="1" cellspacing="0" cellpadding="4">
2382 <tbody>
2383 <tr>
2384 <td>In0</td>
2385 <td>In1</td>
2386 <td>Out</td>
2387 </tr>
2388 <tr>
2389 <td>0</td>
2390 <td>0</td>
2391 <td>0</td>
2392 </tr>
2393 <tr>
2394 <td>0</td>
2395 <td>1</td>
2396 <td>1</td>
2397 </tr>
2398 <tr>
2399 <td>1</td>
2400 <td>0</td>
2401 <td>1</td>
2402 </tr>
2403 <tr>
2404 <td>1</td>
2405 <td>1</td>
2406 <td>0</td>
2407 </tr>
2408 </tbody>
2409</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2410</div>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2411<p> </p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2412<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2413<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2414 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2415 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2416 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2417</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2418</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2419
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2420<!-- ======================================================================= -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2421<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2422 <a name="vectorops">Vector Operations</a>
2423</div>
2424
2425<div class="doc_text">
2426
2427<p>LLVM supports several instructions to represent vector operations in a
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2428target-independent manner. These instructions cover the element-access and
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2429vector-specific operations needed to process vectors effectively. While LLVM
2430does directly support these vector operations, many sophisticated algorithms
2431will want to use target-specific intrinsics to take full advantage of a specific
2432target.</p>
2433
2434</div>
2435
2436<!-- _______________________________________________________________________ -->
2437<div class="doc_subsubsection">
2438 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2439</div>
2440
2441<div class="doc_text">
2442
2443<h5>Syntax:</h5>
2444
2445<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2446 &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]2447</pre>
2448
2449<h5>Overview:</h5>
2450
2451<p>
2452The '<tt>extractelement</tt>' instruction extracts a single scalar
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2453element from a vector at a specified index.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2454</p>
2455
2456
2457<h5>Arguments:</h5>
2458
2459<p>
2460The first operand of an '<tt>extractelement</tt>' instruction is a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2461value of <a href="#t_vector">vector</a> type. The second operand is
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2462an index indicating the position from which to extract the element.
2463The index may be a variable.</p>
2464
2465<h5>Semantics:</h5>
2466
2467<p>
2468The result is a scalar of the same type as the element type of
2469<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2470<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2471results are undefined.
2472</p>
2473
2474<h5>Example:</h5>
2475
2476<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2477 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2478</pre>
2479</div>
2480
2481
2482<!-- _______________________________________________________________________ -->
2483<div class="doc_subsubsection">
2484 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2485</div>
2486
2487<div class="doc_text">
2488
2489<h5>Syntax:</h5>
2490
2491<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2492 &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]2493</pre>
2494
2495<h5>Overview:</h5>
2496
2497<p>
2498The '<tt>insertelement</tt>' instruction inserts a scalar
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2499element into a vector at a specified index.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2500</p>
2501
2502
2503<h5>Arguments:</h5>
2504
2505<p>
2506The first operand of an '<tt>insertelement</tt>' instruction is a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2507value of <a href="#t_vector">vector</a> type. The second operand is a
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2508scalar value whose type must equal the element type of the first
2509operand. The third operand is an index indicating the position at
2510which to insert the value. The index may be a variable.</p>
2511
2512<h5>Semantics:</h5>
2513
2514<p>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2515The result is a vector of the same type as <tt>val</tt>. Its
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2516element values are those of <tt>val</tt> except at position
2517<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2518exceeds the length of <tt>val</tt>, the results are undefined.
2519</p>
2520
2521<h5>Example:</h5>
2522
2523<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2524 %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]2525</pre>
2526</div>
2527
2528<!-- _______________________________________________________________________ -->
2529<div class="doc_subsubsection">
2530 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2531</div>
2532
2533<div class="doc_text">
2534
2535<h5>Syntax:</h5>
2536
2537<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2538 &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]2539</pre>
2540
2541<h5>Overview:</h5>
2542
2543<p>
2544The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2545from two input vectors, returning a vector of the same type.
2546</p>
2547
2548<h5>Arguments:</h5>
2549
2550<p>
2551The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2552with types that match each other and types that match the result of the
2553instruction. The third argument is a shuffle mask, which has the same number
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2554of elements as the other vector type, but whose element type is always 'i32'.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2555</p>
2556
2557<p>
2558The shuffle mask operand is required to be a constant vector with either
2559constant integer or undef values.
2560</p>
2561
2562<h5>Semantics:</h5>
2563
2564<p>
2565The elements of the two input vectors are numbered from left to right across
2566both of the vectors. The shuffle mask operand specifies, for each element of
2567the result vector, which element of the two input registers the result element
2568gets. The element selector may be undef (meaning "don't care") and the second
2569operand may be undef if performing a shuffle from only one vector.
2570</p>
2571
2572<h5>Example:</h5>
2573
2574<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2575 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2576 &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]2577 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2578 &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]2579</pre>
2580</div>
2581
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]2582
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2583<!-- ======================================================================= -->
2584<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2585 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2586</div>
2587
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2588<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2589
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2590<p>A key design point of an SSA-based representation is how it
2591represents memory. In LLVM, no memory locations are in SSA form, which
2592makes things very simple. This section describes how to read, write,
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2593allocate, and free memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2594
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2595</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2596
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2597<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2598<div class="doc_subsubsection">
2599 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2600</div>
2601
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2602<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2603
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2604<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2605
2606<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2607 &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]2608</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2609
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2610<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2611
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2612<p>The '<tt>malloc</tt>' instruction allocates memory from the system
2613heap and returns a pointer to it.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2614
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2615<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2616
2617<p>The '<tt>malloc</tt>' instruction allocates
2618<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswell6e4ca612004-02-24 16:13:56 +0000[diff] [blame]2619bytes of memory from the operating system and returns a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2620appropriate type to the program. If "NumElements" is specified, it is the
2621number of elements allocated. If an alignment is specified, the value result
2622of the allocation is guaranteed to be aligned to at least that boundary. If
2623not specified, or if zero, the target can choose to align the allocation on any
2624convenient boundary.</p>
2625
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2626<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2627
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2628<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2629
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2630<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
2631a pointer is returned.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2632
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2633<h5>Example:</h5>
2634
2635<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2636 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2637
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]2638 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
2639 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
2640 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
2641 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
2642 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2643</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2644</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2645
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2646<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2647<div class="doc_subsubsection">
2648 <a name="i_free">'<tt>free</tt>' Instruction</a>
2649</div>
2650
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2651<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2652
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2653<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2654
2655<pre>
2656 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2657</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2658
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2659<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2660
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2661<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2662memory heap to be reallocated in the future.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2663
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2664<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2665
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2666<p>'<tt>value</tt>' shall be a pointer value that points to a value
2667that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
2668instruction.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2669
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2670<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2671
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2672<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2673after this instruction executes.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2674
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2675<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2676
2677<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2678 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
2679 free [4 x i8]* %array
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2680</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2681</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2682
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2683<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2684<div class="doc_subsubsection">
2685 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
2686</div>
2687
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2688<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2689
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2690<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2691
2692<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2693 &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]2694</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2695
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2696<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2697
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2698<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
2699currently executing function, to be automatically released when this function
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2700returns to its caller.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2701
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2702<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2703
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2704<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2705bytes of memory on the runtime stack, returning a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2706appropriate type to the program. If "NumElements" is specified, it is the
2707number of elements allocated. If an alignment is specified, the value result
2708of the allocation is guaranteed to be aligned to at least that boundary. If
2709not specified, or if zero, the target can choose to align the allocation on any
2710convenient boundary.</p>
2711
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2712<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2713
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2714<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2715
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2716<p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2717memory is automatically released when the function returns. The '<tt>alloca</tt>'
2718instruction is commonly used to represent automatic variables that must
2719have an address available. When the function returns (either with the <tt><a
John Criswelldae2e932005-05-12 16:55:34 +0000[diff] [blame]2720 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]2721instructions), the memory is reclaimed.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2722
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2723<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2724
2725<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2726 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2727 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
2728 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2729 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2730</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2731</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2732
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2733<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2734<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
2735Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2736<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2737<h5>Syntax:</h5>
Christopher Lamb2330e4d2007-04-21 08:16:25 +0000[diff] [blame]2738<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]2739<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2740<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2741<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2742<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2743address from which to load. The pointer must point to a <a
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]2744 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2745marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2746the number or order of execution of this <tt>load</tt> with other
2747volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
2748instructions. </p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2749<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2750<p>The location of memory pointed to is loaded.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2751<h5>Examples:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2752<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2753 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2754 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2755 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2756</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2757</div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2758<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2759<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
2760Instruction</a> </div>
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]2761<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2762<h5>Syntax:</h5>
Christopher Lamb2330e4d2007-04-21 08:16:25 +0000[diff] [blame]2763<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
2764 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]2765</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2766<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2767<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2768<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2769<p>There are two arguments to the '<tt>store</tt>' instruction: a value
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2770to 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]2771operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2772operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2773optimizer is not allowed to modify the number or order of execution of
2774this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
2775 href="#i_store">store</a></tt> instructions.</p>
2776<h5>Semantics:</h5>
2777<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
2778at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2779<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2780<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2781 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2782 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2783 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2784</pre>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2785</div>
2786
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2787<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2788<div class="doc_subsubsection">
2789 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
2790</div>
2791
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2792<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2793<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2794<pre>
2795 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
2796</pre>
2797
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2798<h5>Overview:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2799
2800<p>
2801The '<tt>getelementptr</tt>' instruction is used to get the address of a
2802subelement of an aggregate data structure.</p>
2803
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2804<h5>Arguments:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2805
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2806<p>This instruction takes a list of integer operands that indicate what
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2807elements of the aggregate object to index to. The actual types of the arguments
2808provided depend on the type of the first pointer argument. The
2809'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2810levels 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]2811structure, only <tt>i32</tt> integer constants are allowed. When indexing
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2812into an array or pointer, only integers of 32 or 64 bits are allowed, and will
2813be sign extended to 64-bit values.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2814
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2815<p>For example, let's consider a C code fragment and how it gets
2816compiled to LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2817
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2818<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2819<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2820struct RT {
2821 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]2822 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2823 char C;
2824};
2825struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]2826 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2827 double Y;
2828 struct RT Z;
2829};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2830
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]2831int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2832 return &amp;s[1].Z.B[5][13];
2833}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2834</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2835</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2836
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2837<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2838
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2839<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2840<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2841%RT = type { i8 , [10 x [20 x i32]], i8 }
2842%ST = type { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2843
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2844define i32* %foo(%ST* %s) {
2845entry:
2846 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
2847 ret i32* %reg
2848}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2849</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2850</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2851
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2852<h5>Semantics:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2853
2854<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2855on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2856and <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]2857<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]2858to 64-bits. <a href="#t_struct">Structure</a> types require <tt>i32</tt>
Reid Spencer42ddd842006-12-03 16:53:48 +0000[diff] [blame]2859<b>constants</b>.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2860
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2861<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]2862type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2863}</tt>' type, a structure. The second index indexes into the third element of
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2864the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
2865i8 }</tt>' type, another structure. The third index indexes into the second
2866element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2867array. The two dimensions of the array are subscripted into, yielding an
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2868'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
2869to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2870
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2871<p>Note that it is perfectly legal to index partially through a
2872structure, returning a pointer to an inner element. Because of this,
2873the LLVM code for the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2874
2875<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2876 define i32* %foo(%ST* %s) {
2877 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2878 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
2879 %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]2880 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
2881 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
2882 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2883 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2884</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2885
2886<p>Note that it is undefined to access an array out of bounds: array and
2887pointer indexes must always be within the defined bounds of the array type.
2888The one exception for this rules is zero length arrays. These arrays are
2889defined to be accessible as variable length arrays, which requires access
2890beyond the zero'th element.</p>
2891
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2892<p>The getelementptr instruction is often confusing. For some more insight
2893into how it works, see <a href="GetElementPtr.html">the getelementptr
2894FAQ</a>.</p>
2895
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2896<h5>Example:</h5>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2897
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2898<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2899 <i>; yields [12 x i8]*:aptr</i>
2900 %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2901</pre>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2902</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2903
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2904<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]2905<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2906</div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2907<div class="doc_text">
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]2908<p>The instructions in this category are the conversion instructions (casting)
2909which all take a single operand and a type. They perform various bit conversions
2910on the operand.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2911</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2912
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2913<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2914<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2915 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
2916</div>
2917<div class="doc_text">
2918
2919<h5>Syntax:</h5>
2920<pre>
2921 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2922</pre>
2923
2924<h5>Overview:</h5>
2925<p>
2926The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
2927</p>
2928
2929<h5>Arguments:</h5>
2930<p>
2931The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
2932be 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]2933and type of the result, which must be an <a href="#t_integer">integer</a>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2934type. The bit size of <tt>value</tt> must be larger than the bit size of
2935<tt>ty2</tt>. Equal sized types are not allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2936
2937<h5>Semantics:</h5>
2938<p>
2939The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2940and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
2941larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
2942It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2943
2944<h5>Example:</h5>
2945<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2946 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2947 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
2948 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2949</pre>
2950</div>
2951
2952<!-- _______________________________________________________________________ -->
2953<div class="doc_subsubsection">
2954 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
2955</div>
2956<div class="doc_text">
2957
2958<h5>Syntax:</h5>
2959<pre>
2960 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2961</pre>
2962
2963<h5>Overview:</h5>
2964<p>The '<tt>zext</tt>' instruction zero extends its operand to type
2965<tt>ty2</tt>.</p>
2966
2967
2968<h5>Arguments:</h5>
2969<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]2970<a href="#t_integer">integer</a> type, and a type to cast it to, which must
2971also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2972<tt>value</tt> must be smaller than the bit size of the destination type,
2973<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2974
2975<h5>Semantics:</h5>
2976<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]2977bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2978
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]2979<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]2980
2981<h5>Example:</h5>
2982<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2983 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2984 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2985</pre>
2986</div>
2987
2988<!-- _______________________________________________________________________ -->
2989<div class="doc_subsubsection">
2990 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
2991</div>
2992<div class="doc_text">
2993
2994<h5>Syntax:</h5>
2995<pre>
2996 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2997</pre>
2998
2999<h5>Overview:</h5>
3000<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
3001
3002<h5>Arguments:</h5>
3003<p>
3004The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3005<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3006also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3007<tt>value</tt> must be smaller than the bit size of the destination type,
3008<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3009
3010<h5>Semantics:</h5>
3011<p>
3012The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3013bit (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]3014the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3015
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3016<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]3017
3018<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3019<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3020 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3021 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3022</pre>
3023</div>
3024
3025<!-- _______________________________________________________________________ -->
3026<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]3027 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3028</div>
3029
3030<div class="doc_text">
3031
3032<h5>Syntax:</h5>
3033
3034<pre>
3035 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3036</pre>
3037
3038<h5>Overview:</h5>
3039<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3040<tt>ty2</tt>.</p>
3041
3042
3043<h5>Arguments:</h5>
3044<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
3045 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
3046cast it to. The size of <tt>value</tt> must be larger than the size of
3047<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
3048<i>no-op cast</i>.</p>
3049
3050<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3051<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
3052<a href="#t_floating">floating point</a> type to a smaller
3053<a href="#t_floating">floating point</a> type. If the value cannot fit within
3054the destination type, <tt>ty2</tt>, then the results are undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]3055
3056<h5>Example:</h5>
3057<pre>
3058 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
3059 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
3060</pre>
3061</div>
3062
3063<!-- _______________________________________________________________________ -->
3064<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3065 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3066</div>
3067<div class="doc_text">
3068
3069<h5>Syntax:</h5>
3070<pre>
3071 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3072</pre>
3073
3074<h5>Overview:</h5>
3075<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3076floating point value.</p>
3077
3078<h5>Arguments:</h5>
3079<p>The '<tt>fpext</tt>' instruction takes a
3080<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3081and a <a href="#t_floating">floating point</a> type to cast it to. The source
3082type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3083
3084<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3085<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3086<a href="#t_floating">floating point</a> type to a larger
3087<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3088used to make a <i>no-op cast</i> because it always changes bits. Use
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3089<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]3090
3091<h5>Example:</h5>
3092<pre>
3093 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3094 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3095</pre>
3096</div>
3097
3098<!-- _______________________________________________________________________ -->
3099<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]3100 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3101</div>
3102<div class="doc_text">
3103
3104<h5>Syntax:</h5>
3105<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3106 &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]3107</pre>
3108
3109<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3110<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3111unsigned integer equivalent of type <tt>ty2</tt>.
3112</p>
3113
3114<h5>Arguments:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3115<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]3116<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]3117must be an <a href="#t_integer">integer</a> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3118
3119<h5>Semantics:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3120<p> The '<tt>fptoui</tt>' instruction converts its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3121<a href="#t_floating">floating point</a> operand into the nearest (rounding
3122towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3123the results are undefined.</p>
3124
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3125<h5>Example:</h5>
3126<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3127 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]3128 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3129 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3130</pre>
3131</div>
3132
3133<!-- _______________________________________________________________________ -->
3134<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3135 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3136</div>
3137<div class="doc_text">
3138
3139<h5>Syntax:</h5>
3140<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3141 &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]3142</pre>
3143
3144<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3145<p>The '<tt>fptosi</tt>' instruction converts
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3146<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]3147</p>
3148
3149
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3150<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3151<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]3152<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]3153must also be an <a href="#t_integer">integer</a> type.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3154
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3155<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3156<p>The '<tt>fptosi</tt>' instruction converts its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3157<a href="#t_floating">floating point</a> operand into the nearest (rounding
3158towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3159the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3160
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3161<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3162<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3163 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]3164 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3165 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3166</pre>
3167</div>
3168
3169<!-- _______________________________________________________________________ -->
3170<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3171 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3172</div>
3173<div class="doc_text">
3174
3175<h5>Syntax:</h5>
3176<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3177 &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]3178</pre>
3179
3180<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3181<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3182integer and converts that value to the <tt>ty2</tt> type.</p>
3183
3184
3185<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3186<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]3187<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]3188be a <a href="#t_floating">floating point</a> type.</p>
3189
3190<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3191<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3192integer quantity and converts it to the corresponding floating point value. If
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]3193the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3194
3195
3196<h5>Example:</h5>
3197<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3198 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3199 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3200</pre>
3201</div>
3202
3203<!-- _______________________________________________________________________ -->
3204<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3205 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3206</div>
3207<div class="doc_text">
3208
3209<h5>Syntax:</h5>
3210<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3211 &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]3212</pre>
3213
3214<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3215<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3216integer and converts that value to the <tt>ty2</tt> type.</p>
3217
3218<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3219<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]3220<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]3221a <a href="#t_floating">floating point</a> type.</p>
3222
3223<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3224<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3225integer quantity and converts it to the corresponding floating point value. If
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]3226the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3227
3228<h5>Example:</h5>
3229<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3230 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3231 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3232</pre>
3233</div>
3234
3235<!-- _______________________________________________________________________ -->
3236<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3237 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3238</div>
3239<div class="doc_text">
3240
3241<h5>Syntax:</h5>
3242<pre>
3243 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3244</pre>
3245
3246<h5>Overview:</h5>
3247<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3248the integer type <tt>ty2</tt>.</p>
3249
3250<h5>Arguments:</h5>
3251<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3252must 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]3253<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
3254
3255<h5>Semantics:</h5>
3256<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3257<tt>ty2</tt> by interpreting the pointer value as an integer and either
3258truncating or zero extending that value to the size of the integer type. If
3259<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3260<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]3261are the same size, then nothing is done (<i>no-op cast</i>) other than a type
3262change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3263
3264<h5>Example:</h5>
3265<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3266 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
3267 %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]3268</pre>
3269</div>
3270
3271<!-- _______________________________________________________________________ -->
3272<div class="doc_subsubsection">
3273 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3274</div>
3275<div class="doc_text">
3276
3277<h5>Syntax:</h5>
3278<pre>
3279 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3280</pre>
3281
3282<h5>Overview:</h5>
3283<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3284a pointer type, <tt>ty2</tt>.</p>
3285
3286<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3287<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3288value to cast, and a type to cast it to, which must be a
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]3289<a href="#t_pointer">pointer</a> type.
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3290
3291<h5>Semantics:</h5>
3292<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3293<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3294the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3295size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3296the size of a pointer then a zero extension is done. If they are the same size,
3297nothing is done (<i>no-op cast</i>).</p>
3298
3299<h5>Example:</h5>
3300<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3301 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
3302 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
3303 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3304</pre>
3305</div>
3306
3307<!-- _______________________________________________________________________ -->
3308<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3309 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3310</div>
3311<div class="doc_text">
3312
3313<h5>Syntax:</h5>
3314<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3315 &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]3316</pre>
3317
3318<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3319<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3320<tt>ty2</tt> without changing any bits.</p>
3321
3322<h5>Arguments:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3323<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3324a first class value, and a type to cast it to, which must also be a <a
3325 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
Reid Spencer19b569f2007-01-09 20:08:58 +0000[diff] [blame]3326and the destination type, <tt>ty2</tt>, must be identical. If the source
3327type is a pointer, the destination type must also be a pointer.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3328
3329<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3330<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3331<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3332this conversion. The conversion is done as if the <tt>value</tt> had been
3333stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3334converted to other pointer types with this instruction. To convert pointers to
3335other types, use the <a href="#i_inttoptr">inttoptr</a> or
3336<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3337
3338<h5>Example:</h5>
3339<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3340 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3341 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
3342 %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3343</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3344</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3345
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3346<!-- ======================================================================= -->
3347<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3348<div class="doc_text">
3349<p>The instructions in this category are the "miscellaneous"
3350instructions, which defy better classification.</p>
3351</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3352
3353<!-- _______________________________________________________________________ -->
3354<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3355</div>
3356<div class="doc_text">
3357<h5>Syntax:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3358<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]3359</pre>
3360<h5>Overview:</h5>
3361<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
3362of its two integer operands.</p>
3363<h5>Arguments:</h5>
3364<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3365the condition code indicating the kind of comparison to perform. It is not
3366a value, just a keyword. The possible condition code are:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3367<ol>
3368 <li><tt>eq</tt>: equal</li>
3369 <li><tt>ne</tt>: not equal </li>
3370 <li><tt>ugt</tt>: unsigned greater than</li>
3371 <li><tt>uge</tt>: unsigned greater or equal</li>
3372 <li><tt>ult</tt>: unsigned less than</li>
3373 <li><tt>ule</tt>: unsigned less or equal</li>
3374 <li><tt>sgt</tt>: signed greater than</li>
3375 <li><tt>sge</tt>: signed greater or equal</li>
3376 <li><tt>slt</tt>: signed less than</li>
3377 <li><tt>sle</tt>: signed less or equal</li>
3378</ol>
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3379<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3380<a href="#t_pointer">pointer</a> typed. They must also be identical types.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3381<h5>Semantics:</h5>
3382<p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3383the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3384yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3385<ol>
3386 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3387 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3388 </li>
3389 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3390 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3391 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3392 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3393 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3394 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3395 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3396 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3397 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3398 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3399 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3400 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3401 <li><tt>sge</tt>: interprets the operands as signed values and yields
3402 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3403 <li><tt>slt</tt>: interprets the operands as signed values and yields
3404 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3405 <li><tt>sle</tt>: interprets the operands as signed values and yields
3406 <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]3407</ol>
3408<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3409values are compared as if they were integers.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3410
3411<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3412<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3413 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3414 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3415 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3416 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3417 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3418</pre>
3419</div>
3420
3421<!-- _______________________________________________________________________ -->
3422<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3423</div>
3424<div class="doc_text">
3425<h5>Syntax:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3426<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]3427</pre>
3428<h5>Overview:</h5>
3429<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3430of its floating point operands.</p>
3431<h5>Arguments:</h5>
3432<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3433the condition code indicating the kind of comparison to perform. It is not
3434a value, just a keyword. The possible condition code are:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3435<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3436 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3437 <li><tt>oeq</tt>: ordered and equal</li>
3438 <li><tt>ogt</tt>: ordered and greater than </li>
3439 <li><tt>oge</tt>: ordered and greater than or equal</li>
3440 <li><tt>olt</tt>: ordered and less than </li>
3441 <li><tt>ole</tt>: ordered and less than or equal</li>
3442 <li><tt>one</tt>: ordered and not equal</li>
3443 <li><tt>ord</tt>: ordered (no nans)</li>
3444 <li><tt>ueq</tt>: unordered or equal</li>
3445 <li><tt>ugt</tt>: unordered or greater than </li>
3446 <li><tt>uge</tt>: unordered or greater than or equal</li>
3447 <li><tt>ult</tt>: unordered or less than </li>
3448 <li><tt>ule</tt>: unordered or less than or equal</li>
3449 <li><tt>une</tt>: unordered or not equal</li>
3450 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3451 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3452</ol>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3453<p><i>Ordered</i> means that neither operand is a QNAN while
Reid Spencer93a49852006-12-06 07:08:07 +0000[diff] [blame]3454<i>unordered</i> means that either operand may be a QNAN.</p>
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3455<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be
3456<a href="#t_floating">floating point</a> typed. They must have identical
3457types.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3458<h5>Semantics:</h5>
3459<p>The '<tt>fcmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3460the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3461yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3462<ol>
3463 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3464 <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]3465 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3466 <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]3467 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3468 <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]3469 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3470 <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]3471 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3472 <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]3473 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3474 <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]3475 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3476 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3477 <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]3478 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3479 <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]3480 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3481 <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]3482 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3483 <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]3484 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3485 <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]3486 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3487 <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]3488 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3489 <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]3490 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3491</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3492
3493<h5>Example:</h5>
3494<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3495 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3496 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3497 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3498</pre>
3499</div>
3500
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3501<!-- _______________________________________________________________________ -->
3502<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
3503Instruction</a> </div>
3504<div class="doc_text">
3505<h5>Syntax:</h5>
3506<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
3507<h5>Overview:</h5>
3508<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
3509the SSA graph representing the function.</p>
3510<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3511<p>The type of the incoming values is specified with the first type
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3512field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
3513as arguments, with one pair for each predecessor basic block of the
3514current block. Only values of <a href="#t_firstclass">first class</a>
3515type may be used as the value arguments to the PHI node. Only labels
3516may be used as the label arguments.</p>
3517<p>There must be no non-phi instructions between the start of a basic
3518block and the PHI instructions: i.e. PHI instructions must be first in
3519a basic block.</p>
3520<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3521<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
3522specified by the pair corresponding to the predecessor basic block that executed
3523just prior to the current block.</p>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3524<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3525<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]3526</div>
3527
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3528<!-- _______________________________________________________________________ -->
3529<div class="doc_subsubsection">
3530 <a name="i_select">'<tt>select</tt>' Instruction</a>
3531</div>
3532
3533<div class="doc_text">
3534
3535<h5>Syntax:</h5>
3536
3537<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3538 &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]3539</pre>
3540
3541<h5>Overview:</h5>
3542
3543<p>
3544The '<tt>select</tt>' instruction is used to choose one value based on a
3545condition, without branching.
3546</p>
3547
3548
3549<h5>Arguments:</h5>
3550
3551<p>
3552The '<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.
3553</p>
3554
3555<h5>Semantics:</h5>
3556
3557<p>
3558If the boolean condition evaluates to true, the instruction returns the first
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3559value argument; otherwise, it returns the second value argument.
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3560</p>
3561
3562<h5>Example:</h5>
3563
3564<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3565 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3566</pre>
3567</div>
3568
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]3569
3570<!-- _______________________________________________________________________ -->
3571<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3572 <a name="i_call">'<tt>call</tt>' Instruction</a>
3573</div>
3574
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3575<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3576
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3577<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3578<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]3579 &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]3580</pre>
3581
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3582<h5>Overview:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3583
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3584<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3585
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3586<h5>Arguments:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3587
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3588<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3589
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3590<ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3591 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3592 <p>The optional "tail" marker indicates whether the callee function accesses
3593 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3594 function call is eligible for tail call optimization. Note that calls may
3595 be marked "tail" even if they do not occur before a <a
3596 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3597 </li>
3598 <li>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3599 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3600 convention</a> the call should use. If none is specified, the call defaults
3601 to using C calling conventions.
3602 </li>
3603 <li>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]3604 <p>'<tt>ty</tt>': the type of the call instruction itself which is also
3605 the type of the return value. Functions that return no value are marked
3606 <tt><a href="#t_void">void</a></tt>.</p>
3607 </li>
3608 <li>
3609 <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
3610 value being invoked. The argument types must match the types implied by
3611 this signature. This type can be omitted if the function is not varargs
3612 and if the function type does not return a pointer to a function.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3613 </li>
3614 <li>
3615 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
3616 be invoked. In most cases, this is a direct function invocation, but
3617 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3618 to function value.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3619 </li>
3620 <li>
3621 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencera7e302a2005-05-01 22:22:57 +0000[diff] [blame]3622 function signature argument types. All arguments must be of
3623 <a href="#t_firstclass">first class</a> type. If the function signature
3624 indicates the function accepts a variable number of arguments, the extra
3625 arguments can be specified.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3626 </li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3627</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3628
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3629<h5>Semantics:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3630
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3631<p>The '<tt>call</tt>' instruction is used to cause control flow to
3632transfer to a specified function, with its incoming arguments bound to
3633the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
3634instruction in the called function, control flow continues with the
3635instruction after the function call, and the return value of the
3636function is bound to the result argument. This is a simpler case of
3637the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3638
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3639<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3640
3641<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]3642 %retval = call i32 @test(i32 %argc)
3643 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42);
3644 %X = tail call i32 @foo()
3645 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo()
3646 %Z = call void %foo(i8 97 signext)
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3647</pre>
3648
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3649</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3650
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3651<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3652<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3653 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3654</div>
3655
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3656<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3657
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3658<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3659
3660<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3661 &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]3662</pre>
3663
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3664<h5>Overview:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3665
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3666<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3667the "variable argument" area of a function call. It is used to implement the
3668<tt>va_arg</tt> macro in C.</p>
3669
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3670<h5>Arguments:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3671
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3672<p>This instruction takes a <tt>va_list*</tt> value and the type of
3673the argument. It returns a value of the specified argument type and
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3674increments the <tt>va_list</tt> to point to the next argument. The
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3675actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3676
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3677<h5>Semantics:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3678
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3679<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
3680type from the specified <tt>va_list</tt> and causes the
3681<tt>va_list</tt> to point to the next argument. For more information,
3682see the variable argument handling <a href="#int_varargs">Intrinsic
3683Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3684
3685<p>It is legal for this instruction to be called in a function which does not
3686take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3687function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3688
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3689<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3690href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3691argument.</p>
3692
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3693<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3694
3695<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
3696
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3697</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3698
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3699<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3700<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
3701<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3702
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3703<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3704
3705<p>LLVM supports the notion of an "intrinsic function". These functions have
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]3706well known names and semantics and are required to follow certain restrictions.
3707Overall, these intrinsics represent an extension mechanism for the LLVM
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3708language that does not require changing all of the transformations in LLVM when
Gabor Greif04367bf2007-07-06 22:07:22 +0000[diff] [blame]3709adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3710
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3711<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3712prefix is reserved in LLVM for intrinsic names; thus, function names may not
3713begin with this prefix. Intrinsic functions must always be external functions:
3714you cannot define the body of intrinsic functions. Intrinsic functions may
3715only be used in call or invoke instructions: it is illegal to take the address
3716of an intrinsic function. Additionally, because intrinsic functions are part
3717of the LLVM language, it is required if any are added that they be documented
3718here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3719
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]3720<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
3721a family of functions that perform the same operation but on different data
3722types. Because LLVM can represent over 8 million different integer types,
3723overloading is used commonly to allow an intrinsic function to operate on any
3724integer type. One or more of the argument types or the result type can be
3725overloaded to accept any integer type. Argument types may also be defined as
3726exactly matching a previous argument's type or the result type. This allows an
3727intrinsic function which accepts multiple arguments, but needs all of them to
3728be of the same type, to only be overloaded with respect to a single argument or
3729the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3730
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]3731<p>Overloaded intrinsics will have the names of its overloaded argument types
3732encoded into its function name, each preceded by a period. Only those types
3733which are overloaded result in a name suffix. Arguments whose type is matched
3734against another type do not. For example, the <tt>llvm.ctpop</tt> function can
3735take an integer of any width and returns an integer of exactly the same integer
3736width. This leads to a family of functions such as
3737<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
3738Only one type, the return type, is overloaded, and only one type suffix is
3739required. Because the argument's type is matched against the return type, it
3740does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]3741
3742<p>To learn how to add an intrinsic function, please see the
3743<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3744</p>
3745
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3746</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3747
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3748<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3749<div class="doc_subsection">
3750 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
3751</div>
3752
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3753<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3754
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3755<p>Variable argument support is defined in LLVM with the <a
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3756 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3757intrinsic functions. These functions are related to the similarly
3758named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3759
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3760<p>All of these functions operate on arguments that use a
3761target-specific value type "<tt>va_list</tt>". The LLVM assembly
3762language reference manual does not define what this type is, so all
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3763transformations should be prepared to handle these functions regardless of
3764the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3765
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]3766<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]3767instruction and the variable argument handling intrinsic functions are
3768used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3769
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3770<div class="doc_code">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3771<pre>
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3772define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3773 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3774 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3775 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3776 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3777
3778 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3779 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3780
3781 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3782 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3783 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3784 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3785 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3786
3787 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3788 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3789 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3790}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3791
3792declare void @llvm.va_start(i8*)
3793declare void @llvm.va_copy(i8*, i8*)
3794declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3795</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3796</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3797
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3798</div>
3799
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3800<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3801<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3802 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3803</div>
3804
3805
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3806<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3807<h5>Syntax:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3808<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3809<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3810<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
3811<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
3812href="#i_va_arg">va_arg</a></tt>.</p>
3813
3814<h5>Arguments:</h5>
3815
3816<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
3817
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3818<h5>Semantics:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3819
3820<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
3821macro available in C. In a target-dependent way, it initializes the
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3822<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]3823<tt>va_arg</tt> will produce the first variable argument passed to the function.
3824Unlike 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]3825last argument of the function as the compiler can figure that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3826
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3827</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3828
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3829<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3830<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3831 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3832</div>
3833
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3834<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3835<h5>Syntax:</h5>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3836<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3837<h5>Overview:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3838
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3839<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3840which 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]3841or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3842
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3843<h5>Arguments:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3844
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3845<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]3846
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3847<h5>Semantics:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3848
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3849<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]3850macro available in C. In a target-dependent way, it destroys the
3851<tt>va_list</tt> element to which the argument points. Calls to <a
3852href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
3853<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
3854<tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3855
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3856</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3857
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3858<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3859<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3860 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3861</div>
3862
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3863<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3864
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3865<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3866
3867<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3868 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3869</pre>
3870
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3871<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3872
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3873<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
3874from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3875
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3876<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3877
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3878<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]3879The 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]3880
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3881
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3882<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3883
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3884<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
3885macro available in C. In a target-dependent way, it copies the source
3886<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
3887intrinsic is necessary because the <tt><a href="#int_va_start">
3888llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
3889example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3890
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3891</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3892
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3893<!-- ======================================================================= -->
3894<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3895 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
3896</div>
3897
3898<div class="doc_text">
3899
3900<p>
3901LLVM support for <a href="GarbageCollection.html">Accurate Garbage
3902Collection</a> requires the implementation and generation of these intrinsics.
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3903These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3904stack</a>, as well as garbage collector implementations that require <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3905href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3906Front-ends for type-safe garbage collected languages should generate these
3907intrinsics to make use of the LLVM garbage collectors. For more details, see <a
3908href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
3909</p>
3910</div>
3911
3912<!-- _______________________________________________________________________ -->
3913<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3914 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3915</div>
3916
3917<div class="doc_text">
3918
3919<h5>Syntax:</h5>
3920
3921<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]3922 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3923</pre>
3924
3925<h5>Overview:</h5>
3926
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]3927<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]3928the code generator, and allows some metadata to be associated with it.</p>
3929
3930<h5>Arguments:</h5>
3931
3932<p>The first argument specifies the address of a stack object that contains the
3933root pointer. The second pointer (which must be either a constant or a global
3934value address) contains the meta-data to be associated with the root.</p>
3935
3936<h5>Semantics:</h5>
3937
3938<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
3939location. At compile-time, the code generator generates information to allow
3940the runtime to find the pointer at GC safe points.
3941</p>
3942
3943</div>
3944
3945
3946<!-- _______________________________________________________________________ -->
3947<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3948 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3949</div>
3950
3951<div class="doc_text">
3952
3953<h5>Syntax:</h5>
3954
3955<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]3956 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3957</pre>
3958
3959<h5>Overview:</h5>
3960
3961<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
3962locations, allowing garbage collector implementations that require read
3963barriers.</p>
3964
3965<h5>Arguments:</h5>
3966
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3967<p>The second argument is the address to read from, which should be an address
3968allocated from the garbage collector. The first object is a pointer to the
3969start of the referenced object, if needed by the language runtime (otherwise
3970null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3971
3972<h5>Semantics:</h5>
3973
3974<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
3975instruction, but may be replaced with substantially more complex code by the
3976garbage collector runtime, as needed.</p>
3977
3978</div>
3979
3980
3981<!-- _______________________________________________________________________ -->
3982<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3983 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3984</div>
3985
3986<div class="doc_text">
3987
3988<h5>Syntax:</h5>
3989
3990<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]3991 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3992</pre>
3993
3994<h5>Overview:</h5>
3995
3996<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
3997locations, allowing garbage collector implementations that require write
3998barriers (such as generational or reference counting collectors).</p>
3999
4000<h5>Arguments:</h5>
4001
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]4002<p>The first argument is the reference to store, the second is the start of the
4003object to store it to, and the third is the address of the field of Obj to
4004store to. If the runtime does not require a pointer to the object, Obj may be
4005null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4006
4007<h5>Semantics:</h5>
4008
4009<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
4010instruction, but may be replaced with substantially more complex code by the
4011garbage collector runtime, as needed.</p>
4012
4013</div>
4014
4015
4016
4017<!-- ======================================================================= -->
4018<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4019 <a name="int_codegen">Code Generator Intrinsics</a>
4020</div>
4021
4022<div class="doc_text">
4023<p>
4024These intrinsics are provided by LLVM to expose special features that may only
4025be implemented with code generator support.
4026</p>
4027
4028</div>
4029
4030<!-- _______________________________________________________________________ -->
4031<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4032 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4033</div>
4034
4035<div class="doc_text">
4036
4037<h5>Syntax:</h5>
4038<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4039 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4040</pre>
4041
4042<h5>Overview:</h5>
4043
4044<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]4045The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
4046target-specific value indicating the return address of the current function
4047or one of its callers.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4048</p>
4049
4050<h5>Arguments:</h5>
4051
4052<p>
4053The argument to this intrinsic indicates which function to return the address
4054for. Zero indicates the calling function, one indicates its caller, etc. The
4055argument is <b>required</b> to be a constant integer value.
4056</p>
4057
4058<h5>Semantics:</h5>
4059
4060<p>
4061The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
4062the return address of the specified call frame, or zero if it cannot be
4063identified. The value returned by this intrinsic is likely to be incorrect or 0
4064for arguments other than zero, so it should only be used for debugging purposes.
4065</p>
4066
4067<p>
4068Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]4069aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4070source-language caller.
4071</p>
4072</div>
4073
4074
4075<!-- _______________________________________________________________________ -->
4076<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4077 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4078</div>
4079
4080<div class="doc_text">
4081
4082<h5>Syntax:</h5>
4083<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4084 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4085</pre>
4086
4087<h5>Overview:</h5>
4088
4089<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]4090The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
4091target-specific frame pointer value for the specified stack frame.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4092</p>
4093
4094<h5>Arguments:</h5>
4095
4096<p>
4097The argument to this intrinsic indicates which function to return the frame
4098pointer for. Zero indicates the calling function, one indicates its caller,
4099etc. The argument is <b>required</b> to be a constant integer value.
4100</p>
4101
4102<h5>Semantics:</h5>
4103
4104<p>
4105The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
4106the frame address of the specified call frame, or zero if it cannot be
4107identified. The value returned by this intrinsic is likely to be incorrect or 0
4108for arguments other than zero, so it should only be used for debugging purposes.
4109</p>
4110
4111<p>
4112Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]4113aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4114source-language caller.
4115</p>
4116</div>
4117
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4118<!-- _______________________________________________________________________ -->
4119<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4120 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4121</div>
4122
4123<div class="doc_text">
4124
4125<h5>Syntax:</h5>
4126<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4127 declare i8 *@llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4128</pre>
4129
4130<h5>Overview:</h5>
4131
4132<p>
4133The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4134the function stack, for use with <a href="#int_stackrestore">
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4135<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
4136features like scoped automatic variable sized arrays in C99.
4137</p>
4138
4139<h5>Semantics:</h5>
4140
4141<p>
4142This intrinsic returns a opaque pointer value that can be passed to <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4143href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4144<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
4145<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
4146state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
4147practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
4148that were allocated after the <tt>llvm.stacksave</tt> was executed.
4149</p>
4150
4151</div>
4152
4153<!-- _______________________________________________________________________ -->
4154<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4155 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4156</div>
4157
4158<div class="doc_text">
4159
4160<h5>Syntax:</h5>
4161<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4162 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4163</pre>
4164
4165<h5>Overview:</h5>
4166
4167<p>
4168The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
4169the function stack to the state it was in when the corresponding <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4170href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4171useful for implementing language features like scoped automatic variable sized
4172arrays in C99.
4173</p>
4174
4175<h5>Semantics:</h5>
4176
4177<p>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4178See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4179</p>
4180
4181</div>
4182
4183
4184<!-- _______________________________________________________________________ -->
4185<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4186 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4187</div>
4188
4189<div class="doc_text">
4190
4191<h5>Syntax:</h5>
4192<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4193 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]4194</pre>
4195
4196<h5>Overview:</h5>
4197
4198
4199<p>
4200The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4201a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
4202no
4203effect on the behavior of the program but can change its performance
Chris Lattner2a615362005-02-28 19:47:14 +0000[diff] [blame]4204characteristics.
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4205</p>
4206
4207<h5>Arguments:</h5>
4208
4209<p>
4210<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
4211determining if the fetch should be for a read (0) or write (1), and
4212<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattneraeffb4a2005-03-07 20:31:38 +0000[diff] [blame]4213locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4214<tt>locality</tt> arguments must be constant integers.
4215</p>
4216
4217<h5>Semantics:</h5>
4218
4219<p>
4220This intrinsic does not modify the behavior of the program. In particular,
4221prefetches cannot trap and do not produce a value. On targets that support this
4222intrinsic, the prefetch can provide hints to the processor cache for better
4223performance.
4224</p>
4225
4226</div>
4227
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4228<!-- _______________________________________________________________________ -->
4229<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4230 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4231</div>
4232
4233<div class="doc_text">
4234
4235<h5>Syntax:</h5>
4236<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4237 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4238</pre>
4239
4240<h5>Overview:</h5>
4241
4242
4243<p>
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4244The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
4245(PC) in a region of
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4246code to simulators and other tools. The method is target specific, but it is
4247expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]4248The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnerd07c3f42005-11-15 06:07:55 +0000[diff] [blame]4249after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb3e7afd2006-03-24 07:16:10 +0000[diff] [blame]4250optimizations. The intended use is to be inserted after optimizations to allow
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4251correlations of simulation runs.
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4252</p>
4253
4254<h5>Arguments:</h5>
4255
4256<p>
4257<tt>id</tt> is a numerical id identifying the marker.
4258</p>
4259
4260<h5>Semantics:</h5>
4261
4262<p>
4263This intrinsic does not modify the behavior of the program. Backends that do not
4264support this intrinisic may ignore it.
4265</p>
4266
4267</div>
4268
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4269<!-- _______________________________________________________________________ -->
4270<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4271 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4272</div>
4273
4274<div class="doc_text">
4275
4276<h5>Syntax:</h5>
4277<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4278 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4279</pre>
4280
4281<h5>Overview:</h5>
4282
4283
4284<p>
4285The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
4286counter register (or similar low latency, high accuracy clocks) on those targets
4287that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
4288As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
4289should only be used for small timings.
4290</p>
4291
4292<h5>Semantics:</h5>
4293
4294<p>
4295When directly supported, reading the cycle counter should not modify any memory.
4296Implementations are allowed to either return a application specific value or a
4297system wide value. On backends without support, this is lowered to a constant 0.
4298</p>
4299
4300</div>
4301
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4302<!-- ======================================================================= -->
4303<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4304 <a name="int_libc">Standard C Library Intrinsics</a>
4305</div>
4306
4307<div class="doc_text">
4308<p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4309LLVM provides intrinsics for a few important standard C library functions.
4310These intrinsics allow source-language front-ends to pass information about the
4311alignment of the pointer arguments to the code generator, providing opportunity
4312for more efficient code generation.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4313</p>
4314
4315</div>
4316
4317<!-- _______________________________________________________________________ -->
4318<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4319 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4320</div>
4321
4322<div class="doc_text">
4323
4324<h5>Syntax:</h5>
4325<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4326 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4327 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4328 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4329 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4330</pre>
4331
4332<h5>Overview:</h5>
4333
4334<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4335The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4336location to the destination location.
4337</p>
4338
4339<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4340Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4341intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4342</p>
4343
4344<h5>Arguments:</h5>
4345
4346<p>
4347The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4348the source. The third argument is an integer argument
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4349specifying the number of bytes to copy, and the fourth argument is the alignment
4350of the source and destination locations.
4351</p>
4352
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4353<p>
4354If 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]4355the caller guarantees that both the source and destination pointers are aligned
4356to that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4357</p>
4358
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4359<h5>Semantics:</h5>
4360
4361<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4362The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4363location to the destination location, which are not allowed to overlap. It
4364copies "len" bytes of memory over. If the argument is known to be aligned to
4365some boundary, this can be specified as the fourth argument, otherwise it should
4366be set to 0 or 1.
4367</p>
4368</div>
4369
4370
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4371<!-- _______________________________________________________________________ -->
4372<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4373 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4374</div>
4375
4376<div class="doc_text">
4377
4378<h5>Syntax:</h5>
4379<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4380 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4381 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4382 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4383 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4384</pre>
4385
4386<h5>Overview:</h5>
4387
4388<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4389The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
4390location to the destination location. It is similar to the
4391'<tt>llvm.memcmp</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4392</p>
4393
4394<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4395Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
4396intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4397</p>
4398
4399<h5>Arguments:</h5>
4400
4401<p>
4402The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4403the source. The third argument is an integer argument
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4404specifying the number of bytes to copy, and the fourth argument is the alignment
4405of the source and destination locations.
4406</p>
4407
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4408<p>
4409If 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]4410the caller guarantees that the source and destination pointers are aligned to
4411that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4412</p>
4413
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4414<h5>Semantics:</h5>
4415
4416<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4417The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4418location to the destination location, which may overlap. It
4419copies "len" bytes of memory over. If the argument is known to be aligned to
4420some boundary, this can be specified as the fourth argument, otherwise it should
4421be set to 0 or 1.
4422</p>
4423</div>
4424
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4425
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4426<!-- _______________________________________________________________________ -->
4427<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4428 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4429</div>
4430
4431<div class="doc_text">
4432
4433<h5>Syntax:</h5>
4434<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4435 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4436 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4437 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4438 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4439</pre>
4440
4441<h5>Overview:</h5>
4442
4443<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4444The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4445byte value.
4446</p>
4447
4448<p>
4449Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
4450does not return a value, and takes an extra alignment argument.
4451</p>
4452
4453<h5>Arguments:</h5>
4454
4455<p>
4456The first argument is a pointer to the destination to fill, the second is the
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4457byte value to fill it with, the third argument is an integer
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4458argument specifying the number of bytes to fill, and the fourth argument is the
4459known alignment of destination location.
4460</p>
4461
4462<p>
4463If 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]4464the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4465</p>
4466
4467<h5>Semantics:</h5>
4468
4469<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4470The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
4471the
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4472destination location. If the argument is known to be aligned to some boundary,
4473this can be specified as the fourth argument, otherwise it should be set to 0 or
44741.
4475</p>
4476</div>
4477
4478
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4479<!-- _______________________________________________________________________ -->
4480<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4481 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4482</div>
4483
4484<div class="doc_text">
4485
4486<h5>Syntax:</h5>
4487<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4488 declare float @llvm.sqrt.f32(float %Val)
4489 declare double @llvm.sqrt.f64(double %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4490</pre>
4491
4492<h5>Overview:</h5>
4493
4494<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4495The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4496returning the same value as the libm '<tt>sqrt</tt>' function would. Unlike
4497<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
4498negative numbers (which allows for better optimization).
4499</p>
4500
4501<h5>Arguments:</h5>
4502
4503<p>
4504The argument and return value are floating point numbers of the same type.
4505</p>
4506
4507<h5>Semantics:</h5>
4508
4509<p>
Dan Gohmand6257fe2007-07-16 14:37:41 +0000[diff] [blame]4510This function returns the sqrt of the specified operand if it is a nonnegative
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4511floating point number.
4512</p>
4513</div>
4514
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4515<!-- _______________________________________________________________________ -->
4516<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4517 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4518</div>
4519
4520<div class="doc_text">
4521
4522<h5>Syntax:</h5>
4523<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4524 declare float @llvm.powi.f32(float %Val, i32 %power)
4525 declare double @llvm.powi.f64(double %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4526</pre>
4527
4528<h5>Overview:</h5>
4529
4530<p>
4531The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
4532specified (positive or negative) power. The order of evaluation of
4533multiplications is not defined.
4534</p>
4535
4536<h5>Arguments:</h5>
4537
4538<p>
4539The second argument is an integer power, and the first is a value to raise to
4540that power.
4541</p>
4542
4543<h5>Semantics:</h5>
4544
4545<p>
4546This function returns the first value raised to the second power with an
4547unspecified sequence of rounding operations.</p>
4548</div>
4549
4550
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4551<!-- ======================================================================= -->
4552<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4553 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4554</div>
4555
4556<div class="doc_text">
4557<p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4558LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4559These allow efficient code generation for some algorithms.
4560</p>
4561
4562</div>
4563
4564<!-- _______________________________________________________________________ -->
4565<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4566 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4567</div>
4568
4569<div class="doc_text">
4570
4571<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4572<p>This is an overloaded intrinsic function. You can use bswap on any integer
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4573type that is an even number of bytes (i.e. BitWidth % 16 == 0).
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4574<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4575 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
4576 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
4577 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4578</pre>
4579
4580<h5>Overview:</h5>
4581
4582<p>
Reid Spencer338ea092007-04-02 02:25:19 +0000[diff] [blame]4583The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4584values with an even number of bytes (positive multiple of 16 bits). These are
4585useful for performing operations on data that is not in the target's native
4586byte order.
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4587</p>
4588
4589<h5>Semantics:</h5>
4590
4591<p>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4592The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4593and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
4594intrinsic returns an i32 value that has the four bytes of the input i32
4595swapped, 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]4596i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
4597<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4598additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4599</p>
4600
4601</div>
4602
4603<!-- _______________________________________________________________________ -->
4604<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4605 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4606</div>
4607
4608<div class="doc_text">
4609
4610<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4611<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
4612width. Not all targets support all bit widths however.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4613<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4614 declare i8 @llvm.ctpop.i8 (i8 &lt;src&gt;)
4615 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4616 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4617 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
4618 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4619</pre>
4620
4621<h5>Overview:</h5>
4622
4623<p>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4624The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
4625value.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4626</p>
4627
4628<h5>Arguments:</h5>
4629
4630<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]4631The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4632integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4633</p>
4634
4635<h5>Semantics:</h5>
4636
4637<p>
4638The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
4639</p>
4640</div>
4641
4642<!-- _______________________________________________________________________ -->
4643<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]4644 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4645</div>
4646
4647<div class="doc_text">
4648
4649<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4650<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
4651integer bit width. Not all targets support all bit widths however.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4652<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4653 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
4654 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4655 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4656 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
4657 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4658</pre>
4659
4660<h5>Overview:</h5>
4661
4662<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4663The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
4664leading zeros in a variable.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4665</p>
4666
4667<h5>Arguments:</h5>
4668
4669<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]4670The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4671integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4672</p>
4673
4674<h5>Semantics:</h5>
4675
4676<p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4677The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
4678in 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]4679of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4680</p>
4681</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4682
4683
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4684
4685<!-- _______________________________________________________________________ -->
4686<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]4687 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4688</div>
4689
4690<div class="doc_text">
4691
4692<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4693<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
4694integer bit width. Not all targets support all bit widths however.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4695<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4696 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
4697 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4698 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4699 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
4700 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4701</pre>
4702
4703<h5>Overview:</h5>
4704
4705<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4706The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
4707trailing zeros.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4708</p>
4709
4710<h5>Arguments:</h5>
4711
4712<p>
4713The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4714integer type. The return type must match the argument type.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4715</p>
4716
4717<h5>Semantics:</h5>
4718
4719<p>
4720The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
4721in a variable. If the src == 0 then the result is the size in bits of the type
4722of src. For example, <tt>llvm.cttz(2) = 1</tt>.
4723</p>
4724</div>
4725
Reid Spencer497d93e2007-04-01 08:27:01 +0000[diff] [blame]4726<!-- _______________________________________________________________________ -->
4727<div class="doc_subsubsection">
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]4728 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4729</div>
4730
4731<div class="doc_text">
4732
4733<h5>Syntax:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]4734<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4735on any integer bit width.
4736<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4737 declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
4738 declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4739</pre>
4740
4741<h5>Overview:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]4742<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4743range of bits from an integer value and returns them in the same bit width as
4744the original value.</p>
4745
4746<h5>Arguments:</h5>
4747<p>The first argument, <tt>%val</tt> and the result may be integer types of
4748any bit width but they must have the same bit width. The second and third
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4749arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4750
4751<h5>Semantics:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]4752<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4753of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
4754<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
4755operates in forward mode.</p>
4756<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
4757right by <tt>%loBit</tt> bits and then ANDing it with a mask with
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4758only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
4759<ol>
4760 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
4761 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
4762 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
4763 to determine the number of bits to retain.</li>
4764 <li>A mask of the retained bits is created by shifting a -1 value.</li>
4765 <li>The mask is ANDed with <tt>%val</tt> to produce the result.
4766</ol>
Reid Spencerd6a85b52007-05-14 16:14:57 +0000[diff] [blame]4767<p>In reverse mode, a similar computation is made except that the bits are
4768returned in the reverse order. So, for example, if <tt>X</tt> has the value
4769<tt>i16 0x0ACF (101011001111)</tt> and we apply
4770<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
4771<tt>i16 0x0026 (000000100110)</tt>.</p>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4772</div>
4773
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]4774<div class="doc_subsubsection">
4775 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
4776</div>
4777
4778<div class="doc_text">
4779
4780<h5>Syntax:</h5>
4781<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
4782on any integer bit width.
4783<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4784 declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
4785 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]4786</pre>
4787
4788<h5>Overview:</h5>
4789<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
4790of bits in an integer value with another integer value. It returns the integer
4791with the replaced bits.</p>
4792
4793<h5>Arguments:</h5>
4794<p>The first argument, <tt>%val</tt> and the result may be integer types of
4795any bit width but they must have the same bit width. <tt>%val</tt> is the value
4796whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
4797integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
4798type since they specify only a bit index.</p>
4799
4800<h5>Semantics:</h5>
4801<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
4802of operation: forwards and reverse. If <tt>%lo</tt> is greater than
4803<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
4804operates in forward mode.</p>
4805<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
4806truncating it down to the size of the replacement area or zero extending it
4807up to that size.</p>
4808<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
4809are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
4810in <tt>%repl</tt> replaces the <tt>%lo</tt>th bit in <tt>%val</tt> and etc. up
4811to the <tt>%hi</tt>th bit.
Reid Spencerc6749c42007-05-14 16:50:20 +0000[diff] [blame]4812<p>In reverse mode, a similar computation is made except that the bits are
4813reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
4814<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]4815<h5>Examples:</h5>
4816<pre>
Reid Spencerf0dbf642007-04-12 01:03:03 +0000[diff] [blame]4817 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
Reid Spencerc6749c42007-05-14 16:50:20 +0000[diff] [blame]4818 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
4819 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
4820 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
Reid Spencerf0dbf642007-04-12 01:03:03 +0000[diff] [blame]4821 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]4822</pre>
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]4823</div>
4824
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4825<!-- ======================================================================= -->
4826<div class="doc_subsection">
4827 <a name="int_debugger">Debugger Intrinsics</a>
4828</div>
4829
4830<div class="doc_text">
4831<p>
4832The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
4833are described in the <a
4834href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
4835Debugging</a> document.
4836</p>
4837</div>
4838
4839
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]4840<!-- ======================================================================= -->
4841<div class="doc_subsection">
4842 <a name="int_eh">Exception Handling Intrinsics</a>
4843</div>
4844
4845<div class="doc_text">
4846<p> The LLVM exception handling intrinsics (which all start with
4847<tt>llvm.eh.</tt> prefix), are described in the <a
4848href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
4849Handling</a> document. </p>
4850</div>
4851
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]4852<!-- ======================================================================= -->
4853<div class="doc_subsection">
Chandler Carruth2eb93b32007-07-20 19:34:37 +0000[diff] [blame]4854 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
4855</div>
4856
4857<div class="doc_text">
4858<p>
4859 These intrinsic functions expand the "universal IR" of LLVM to represent
4860 hardware constructs for atomic operations and memory synchronization. This
4861 provides an interface to the hardware, not an interface to the programmer. It
4862 is aimed at a low enough level to allow any programming models or APIs which
4863 need atomic behaviors to map cleanly onto it. It is also modeled primarily on
Chandler Carruth6813c152007-07-20 20:14:52 +0000[diff] [blame]4864 hardware behavior. Just as hardware provides a "universal IR" for source
Chandler Carruth2eb93b32007-07-20 19:34:37 +0000[diff] [blame]4865 languages, it also provides a starting point for developing a "universal"
4866 atomic operation and synchronization IR.
4867</p>
4868<p>
4869 These do <em>not</em> form an API such as high-level threading libraries,
4870 software transaction memory systems, atomic primitives, and intrinsic
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]4871 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
Chandler Carruth2eb93b32007-07-20 19:34:37 +0000[diff] [blame]4872 application libraries. The hardware interface provided by LLVM should allow
4873 a clean implementation of all of these APIs and parallel programming models.
4874 No one model or paradigm should be selected above others unless the hardware
4875 itself ubiquitously does so.
4876</p>
4877</div>
4878
4879<!-- _______________________________________________________________________ -->
4880<div class="doc_subsubsection">
4881 <a name="int_lcs">'<tt>llvm.atomic.lcs.*</tt>' Intrinsic</a>
4882</div>
4883<div class="doc_text">
4884<h5>Syntax:</h5>
4885<p>
4886 This is an overloaded intrinsic. You can use <tt>llvm.atomic.lcs</tt> on any
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]4887 integer bit width. Not all targets support all bit widths however.</p>
Chandler Carruth2eb93b32007-07-20 19:34:37 +0000[diff] [blame]4888<pre>
4889declare i8 @llvm.atomic.lcs.i8.i8p.i8.i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
4890declare i16 @llvm.atomic.lcs.i16.i16p.i16.i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
4891declare i32 @llvm.atomic.lcs.i32.i32p.i32.i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
4892declare i64 @llvm.atomic.lcs.i64.i64p.i64.i64( i64* &lt;ptr&gt;, i64 &lt;cmp&gt;, i64 &lt;val&gt; )
4893</pre>
Chandler Carruth2eb93b32007-07-20 19:34:37 +0000[diff] [blame]4894<h5>Overview:</h5>
4895<p>
Chandler Carruth6813c152007-07-20 20:14:52 +0000[diff] [blame]4896 This loads a value in memory and compares it to a given value. If they are
4897 equal, it stores a new value into the memory.
Chandler Carruth2eb93b32007-07-20 19:34:37 +0000[diff] [blame]4898</p>
4899<h5>Arguments:</h5>
4900<p>
4901 The <tt>llvm.atomic.lcs</tt> intrinsic takes three arguments. The result as
4902 well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
4903 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
4904 this integer type. While any bit width integer may be used, targets may only
4905 lower representations they support in hardware.
4906</p>
4907<h5>Semantics:</h5>
4908<p>
4909 This entire intrinsic must be executed atomically. It first loads the value
Chandler Carruth6813c152007-07-20 20:14:52 +0000[diff] [blame]4910 in memory pointed to by <tt>ptr</tt> and compares it with the value
4911 <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
4912 loaded value is yielded in all cases. This provides the equivalent of an
4913 atomic compare-and-swap operation within the SSA framework.
Chandler Carruth2eb93b32007-07-20 19:34:37 +0000[diff] [blame]4914</p>
4915<h5>Examples:</h5>
4916<pre>
4917%ptr = malloc i32
4918 store i32 4, %ptr
4919
4920%val1 = add i32 4, 4
4921%result1 = call i32 @llvm.atomic.lcs( i32* %ptr, i32 4, %val1 )
4922 <i>; yields {i32}:result1 = 4</i>
4923%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
4924%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
4925
4926%val2 = add i32 1, 1
4927%result2 = call i32 @llvm.atomic.lcs( i32* %ptr, i32 5, %val2 )
4928 <i>; yields {i32}:result2 = 8</i>
4929%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
4930%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
4931</pre>
4932</div>
4933
4934<!-- _______________________________________________________________________ -->
4935<div class="doc_subsubsection">
4936 <a name="int_ls">'<tt>llvm.atomic.ls.*</tt>' Intrinsic</a>
4937</div>
4938<div class="doc_text">
4939<h5>Syntax:</h5>
4940<p>
4941 This is an overloaded intrinsic. You can use <tt>llvm.atomic.ls</tt> on any
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]4942 integer bit width. Not all targets support all bit widths however.</p>
Chandler Carruth2eb93b32007-07-20 19:34:37 +0000[diff] [blame]4943<pre>
4944declare i8 @llvm.atomic.ls.i8.i8p.i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
4945declare i16 @llvm.atomic.ls.i16.i16p.i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
4946declare i32 @llvm.atomic.ls.i32.i32p.i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
4947declare i64 @llvm.atomic.ls.i64.i64p.i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
4948</pre>
Chandler Carruth2eb93b32007-07-20 19:34:37 +0000[diff] [blame]4949<h5>Overview:</h5>
4950<p>
Chandler Carruth6813c152007-07-20 20:14:52 +0000[diff] [blame]4951 This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
4952 the value from memory. It then stores the value in <tt>val</tt> in the memory
4953 at <tt>ptr</tt>.
Chandler Carruth2eb93b32007-07-20 19:34:37 +0000[diff] [blame]4954</p>
4955<h5>Arguments:</h5>
4956<p>
4957 The <tt>llvm.atomic.ls</tt> intrinsic takes two arguments. Both the
4958 <tt>val</tt> argument and the result must be integers of the same bit width.
4959 The first argument, <tt>ptr</tt>, must be a pointer to a value of this
4960 integer type. The targets may only lower integer representations they
4961 support.
4962</p>
4963<h5>Semantics:</h5>
4964<p>
4965 This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
4966 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
4967 equivalent of an atomic swap operation within the SSA framework.
4968</p>
4969<h5>Examples:</h5>
4970<pre>
4971%ptr = malloc i32
4972 store i32 4, %ptr
4973
4974%val1 = add i32 4, 4
4975%result1 = call i32 @llvm.atomic.ls( i32* %ptr, i32 %val1 )
4976 <i>; yields {i32}:result1 = 4</i>
4977%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
4978%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
4979
4980%val2 = add i32 1, 1
4981%result2 = call i32 @llvm.atomic.ls( i32* %ptr, i32 %val2 )
4982 <i>; yields {i32}:result2 = 8</i>
4983%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
4984%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
4985</pre>
4986 </div>
4987
4988<!-- _______________________________________________________________________ -->
4989<div class="doc_subsubsection">
4990 <a name="int_las">'<tt>llvm.atomic.las.*</tt>' Intrinsic</a>
4991</div>
4992<div class="doc_text">
4993<h5>Syntax:</h5>
4994<p>
4995 This is an overloaded intrinsic. You can use <tt>llvm.atomic.las</tt> on any
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]4996 integer bit width. Not all targets support all bit widths however.</p>
Chandler Carruth2eb93b32007-07-20 19:34:37 +0000[diff] [blame]4997<pre>
4998declare i8 @llvm.atomic.las.i8.i8p.i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
4999declare i16 @llvm.atomic.las.i16.i16p.i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
5000declare i32 @llvm.atomic.las.i32.i32p.i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
5001declare i64 @llvm.atomic.las.i64.i64p.i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
5002</pre>
Chandler Carruth2eb93b32007-07-20 19:34:37 +0000[diff] [blame]5003<h5>Overview:</h5>
5004<p>
Chandler Carruth6813c152007-07-20 20:14:52 +0000[diff] [blame]5005 This intrinsic adds <tt>delta</tt> to the value stored in memory at
Chandler Carruth2eb93b32007-07-20 19:34:37 +0000[diff] [blame]5006 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
5007</p>
5008<h5>Arguments:</h5>
5009<p>
5010 The intrinsic takes two arguments, the first a pointer to an integer value
5011 and the second an integer value. The result is also an integer value. These
5012 integer types can have any bit width, but they must all have the same bit
5013 width. The targets may only lower integer representations they support.
5014</p>
5015<h5>Semantics:</h5>
5016<p>
5017 This intrinsic does a series of operations atomically. It first loads the
5018 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
5019 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
5020</p>
5021<h5>Examples:</h5>
5022<pre>
5023%ptr = malloc i32
5024 store i32 4, %ptr
5025%result1 = call i32 @llvm.atomic.las( i32* %ptr, i32 4 )
5026 <i>; yields {i32}:result1 = 4</i>
5027%result2 = call i32 @llvm.atomic.las( i32* %ptr, i32 2 )
5028 <i>; yields {i32}:result2 = 8</i>
5029%result3 = call i32 @llvm.atomic.las( i32* %ptr, i32 5 )
5030 <i>; yields {i32}:result3 = 10</i>
5031%memval = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
5032</pre>
5033</div>
5034
5035<!-- _______________________________________________________________________ -->
5036<div class="doc_subsubsection">
5037 <a name="int_lss">'<tt>llvm.atomic.lss.*</tt>' Intrinsic</a>
5038</div>
5039<div class="doc_text">
5040<h5>Syntax:</h5>
5041<p>
5042 This is an overloaded intrinsic. You can use <tt>llvm.atomic.lss</tt> on any
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]5043 integer bit width. Not all targets support all bit widths however.</p>
Chandler Carruth2eb93b32007-07-20 19:34:37 +0000[diff] [blame]5044<pre>
5045declare i8 @llvm.atomic.lss.i8.i8.i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
5046declare i16 @llvm.atomic.lss.i16.i16.i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
5047declare i32 @llvm.atomic.lss.i32.i32.i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
5048declare i64 @llvm.atomic.lss.i64.i64.i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
5049</pre>
Chandler Carruth2eb93b32007-07-20 19:34:37 +0000[diff] [blame]5050<h5>Overview:</h5>
5051<p>
Chandler Carruth6813c152007-07-20 20:14:52 +0000[diff] [blame]5052 This intrinsic subtracts <tt>delta</tt> from the value stored in memory at
5053 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
Chandler Carruth2eb93b32007-07-20 19:34:37 +0000[diff] [blame]5054</p>
5055<h5>Arguments:</h5>
5056<p>
5057 The intrinsic takes two arguments, the first a pointer to an integer value
5058 and the second an integer value. The result is also an integer value. These
5059 integer types can have any bit width, but they must all have the same bit
5060 width. The targets may only lower integer representations they support.
5061</p>
5062<h5>Semantics:</h5>
5063<p>
5064 This intrinsic does a series of operations atomically. It first loads the
5065 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>,
5066 stores the result to <tt>ptr</tt>. It yields the original value stored
5067 at <tt>ptr</tt>.
5068</p>
5069<h5>Examples:</h5>
5070<pre>
5071%ptr = malloc i32
5072 store i32 32, %ptr
5073%result1 = call i32 @llvm.atomic.lss( i32* %ptr, i32 4 )
5074 <i>; yields {i32}:result1 = 32</i>
5075%result2 = call i32 @llvm.atomic.lss( i32* %ptr, i32 2 )
5076 <i>; yields {i32}:result2 = 28</i>
5077%result3 = call i32 @llvm.atomic.lss( i32* %ptr, i32 5 )
5078 <i>; yields {i32}:result3 = 26</i>
5079%memval = load i32* %ptr <i>; yields {i32}:memval1 = 21</i>
5080</pre>
5081</div>
5082
5083<!-- _______________________________________________________________________ -->
5084<div class="doc_subsubsection">
5085 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
5086</div>
5087<div class="doc_text">
5088<h5>Syntax:</h5>
Chandler Carruth2eb93b32007-07-20 19:34:37 +0000[diff] [blame]5089<pre>
5090declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt; )
5091</pre>
Chandler Carruth2eb93b32007-07-20 19:34:37 +0000[diff] [blame]5092<h5>Overview:</h5>
5093<p>
5094 The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
5095 specific pairs of memory access types.
5096</p>
5097<h5>Arguments:</h5>
5098<p>
5099 The <tt>llvm.memory.barrier</tt> intrinsic requires four boolean arguments.
5100 Each argument enables a specific barrier as listed below.
Reid Spencer1cff4082007-07-20 20:03:33 +0000[diff] [blame]5101</p>
Chandler Carruth2eb93b32007-07-20 19:34:37 +0000[diff] [blame]5102 <ul>
5103 <li><tt>ll</tt>: load-load barrier</li>
5104 <li><tt>ls</tt>: load-store barrier</li>
5105 <li><tt>sl</tt>: store-load barrier</li>
5106 <li><tt>ss</tt>: store-store barrier</li>
5107 </ul>
Chandler Carruth2eb93b32007-07-20 19:34:37 +0000[diff] [blame]5108<h5>Semantics:</h5>
5109<p>
5110 This intrinsic causes the system to enforce some ordering constraints upon
5111 the loads and stores of the program. This barrier does not indicate
5112 <em>when</em> any events will occur, it only enforces an <em>order</em> in
5113 which they occur. For any of the specified pairs of load and store operations
5114 (f.ex. load-load, or store-load), all of the first operations preceding the
5115 barrier will complete before any of the second operations succeeding the
5116 barrier begin. Specifically the semantics for each pairing is as follows:
Reid Spencer1cff4082007-07-20 20:03:33 +0000[diff] [blame]5117</p>
Chandler Carruth2eb93b32007-07-20 19:34:37 +0000[diff] [blame]5118 <ul>
5119 <li><tt>ll</tt>: All loads before the barrier must complete before any load
5120 after the barrier begins.</li>
5121 <li><tt>ls</tt>: All loads before the barrier must complete before any
5122 store after the barrier begins.</li>
5123 <li><tt>ss</tt>: All stores before the barrier must complete before any
5124 store after the barrier begins.</li>
5125 <li><tt>sl</tt>: All stores before the barrier must complete before any
5126 load after the barrier begins.</li>
5127 </ul>
Reid Spencer1cff4082007-07-20 20:03:33 +0000[diff] [blame]5128<p>
Chandler Carruth2eb93b32007-07-20 19:34:37 +0000[diff] [blame]5129 These semantics are applied with a logical "and" behavior when more than one
5130 is enabled in a single memory barrier intrinsic.
5131</p>
5132<h5>Example:</h5>
5133<pre>
5134%ptr = malloc i32
5135 store i32 4, %ptr
5136
5137%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
5138 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
5139 <i>; guarantee the above finishes</i>
5140 store i32 8, %ptr <i>; before this begins</i>
5141</pre>
5142</div>
5143
5144<!-- ======================================================================= -->
5145<div class="doc_subsection">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5146 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5147</div>
5148
5149<div class="doc_text">
5150<p>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5151 This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5152 the <tt>nest</tt> attribute, from a function. The result is a callable
5153 function pointer lacking the nest parameter - the caller does not need
5154 to provide a value for it. Instead, the value to use is stored in
5155 advance in a "trampoline", a block of memory usually allocated
5156 on the stack, which also contains code to splice the nest value into the
5157 argument list. This is used to implement the GCC nested function address
5158 extension.
5159</p>
5160<p>
5161 For example, if the function is
5162 <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^]5163 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]5164<pre>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5165 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
5166 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
5167 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
5168 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5169</pre>
Bill Wendling03295ca2007-09-22 09:23:55 +0000[diff] [blame^]5170 <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
5171 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5172</div>
5173
5174<!-- _______________________________________________________________________ -->
5175<div class="doc_subsubsection">
5176 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
5177</div>
5178<div class="doc_text">
5179<h5>Syntax:</h5>
5180<pre>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5181declare 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]5182</pre>
5183<h5>Overview:</h5>
5184<p>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5185 This fills the memory pointed to by <tt>tramp</tt> with code
5186 and returns a function pointer suitable for executing it.
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5187</p>
5188<h5>Arguments:</h5>
5189<p>
5190 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
5191 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
5192 and sufficiently aligned block of memory; this memory is written to by the
Duncan Sandsc00c2ba2007-08-22 23:39:54 +0000[diff] [blame]5193 intrinsic. Note that the size and the alignment are target-specific - LLVM
5194 currently provides no portable way of determining them, so a front-end that
5195 generates this intrinsic needs to have some target-specific knowledge.
5196 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]5197</p>
5198<h5>Semantics:</h5>
5199<p>
5200 The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5201 dependent code, turning it into a function. A pointer to this function is
5202 returned, but needs to be bitcast to an
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5203 <a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5204 before being called. The new function's signature is the same as that of
5205 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
5206 removed. At most one such <tt>nest</tt> argument is allowed, and it must be
5207 of pointer type. Calling the new function is equivalent to calling
5208 <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
5209 missing <tt>nest</tt> argument. If, after calling
5210 <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
5211 modified, then the effect of any later call to the returned function pointer is
5212 undefined.
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5213</p>
5214</div>
5215
5216<!-- ======================================================================= -->
5217<div class="doc_subsection">
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5218 <a name="int_general">General Intrinsics</a>
5219</div>
5220
5221<div class="doc_text">
5222<p> This class of intrinsics is designed to be generic and has
5223no specific purpose. </p>
5224</div>
5225
5226<!-- _______________________________________________________________________ -->
5227<div class="doc_subsubsection">
5228 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
5229</div>
5230
5231<div class="doc_text">
5232
5233<h5>Syntax:</h5>
5234<pre>
Tanya Lattnerd2e84422007-06-18 23:42:37 +0000[diff] [blame]5235 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]5236</pre>
5237
5238<h5>Overview:</h5>
5239
5240<p>
5241The '<tt>llvm.var.annotation</tt>' intrinsic
5242</p>
5243
5244<h5>Arguments:</h5>
5245
5246<p>
Tanya Lattnerd2e84422007-06-18 23:42:37 +0000[diff] [blame]5247The first argument is a pointer to a value, the second is a pointer to a
5248global string, the third is a pointer to a global string which is the source
5249file name, and the last argument is the line number.
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5250</p>
5251
5252<h5>Semantics:</h5>
5253
5254<p>
5255This intrinsic allows annotation of local variables with arbitrary strings.
5256This can be useful for special purpose optimizations that want to look for these
5257 annotations. These have no other defined use, they are ignored by code
5258 generation and optimization.
5259</div>
5260
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5261<!-- _______________________________________________________________________ -->
5262<div class="doc_subsubsection">
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]5263 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5264</div>
5265
5266<div class="doc_text">
5267
5268<h5>Syntax:</h5>
Tanya Lattner39cfba62007-09-21 23:56:27 +0000[diff] [blame]5269<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
5270any integer bit width.
5271</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5272<pre>
Tanya Lattnerd3989a82007-09-22 00:03:01 +0000[diff] [blame]5273 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5274 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5275 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5276 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5277 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]5278</pre>
5279
5280<h5>Overview:</h5>
Tanya Lattner39cfba62007-09-21 23:56:27 +0000[diff] [blame]5281
5282<p>
5283The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5284</p>
5285
5286<h5>Arguments:</h5>
5287
5288<p>
5289The first argument is an integer value (result of some expression),
5290the second is a pointer to a global string, the third is a pointer to a global
5291string which is the source file name, and the last argument is the line number.
Tanya Lattner39cfba62007-09-21 23:56:27 +0000[diff] [blame]5292It returns the value of the first argument.
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5293</p>
5294
5295<h5>Semantics:</h5>
5296
5297<p>
5298This intrinsic allows annotations to be put on arbitrary expressions
5299with arbitrary strings. This can be useful for special purpose optimizations
5300that want to look for these annotations. These have no other defined use, they
5301are ignored by code generation and optimization.
5302</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]5303
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5304<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5305<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]5306<address>
5307 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
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5310 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!" /></a>
5311
5312 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]5313 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]5314 Last modified: $Date$
5315</address>
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5317</html>