Gitiles
Code Review Sign In
gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / b158692a10262233677057d7dd8f3044e93ee3ee / . / docs / LangRef.html
blob: 7cfa05205cead0d9264a0acfdabdf00c95d263c7 [file] [log] [blame]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
2 "http://www.w3.org/TR/html4/strict.dtd">
3<html>
4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]8 <meta name="description"
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]9 content="LLVM Assembly Language Reference Manual.">
10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
12
13<body>
14
15<div class="doc_title"> LLVM Language Reference Manual </div>
16<ol>
17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendlinge2753242009-07-20 02:41:50 +0000[diff] [blame]25 <li><a href="#linkage_private">'<tt>private</tt>' Linkage</a></li>
26 <li><a href="#linkage_linker_private">'<tt>linker_private</tt>' Linkage</a></li>
27 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
28 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
29 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
30 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
31 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
32 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
33 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
Chris Lattner0fee5c22009-10-10 18:26:06 +0000[diff] [blame]34 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendlinge2753242009-07-20 02:41:50 +0000[diff] [blame]35 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
36 <li><a href="#linkage_external">'<tt>externally visible</tt>' Linkage</a></li>
37 <li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
38 <li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]39 </ol>
40 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]41 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]42 <li><a href="#namedtypes">Named Types</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]43 <li><a href="#globalvars">Global Variables</a></li>
44 <li><a href="#functionstructure">Functions</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]45 <li><a href="#aliasstructure">Aliases</a></li>
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]46 <li><a href="#namedmetadatastructure">Named Metadata</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]47 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]48 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]49 <li><a href="#gc">Garbage Collector Names</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]50 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
51 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]52 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]53 </ol>
54 </li>
55 <li><a href="#typesystem">Type System</a>
56 <ol>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]57 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]58 <li><a href="#t_primitive">Primitive Types</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]59 <ol>
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]60 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]61 <li><a href="#t_floating">Floating Point Types</a></li>
62 <li><a href="#t_void">Void Type</a></li>
63 <li><a href="#t_label">Label Type</a></li>
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]64 <li><a href="#t_metadata">Metadata Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]65 </ol>
66 </li>
67 <li><a href="#t_derived">Derived Types</a>
68 <ol>
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]69 <li><a href="#t_aggregate">Aggregate Types</a>
70 <ol>
71 <li><a href="#t_array">Array Type</a></li>
72 <li><a href="#t_struct">Structure Type</a></li>
73 <li><a href="#t_pstruct">Packed Structure Type</a></li>
74 <li><a href="#t_union">Union Type</a></li>
75 <li><a href="#t_vector">Vector Type</a></li>
76 </ol>
77 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]78 <li><a href="#t_function">Function Type</a></li>
79 <li><a href="#t_pointer">Pointer Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]80 <li><a href="#t_opaque">Opaque Type</a></li>
81 </ol>
82 </li>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]83 <li><a href="#t_uprefs">Type Up-references</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]84 </ol>
85 </li>
86 <li><a href="#constants">Constants</a>
87 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]88 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]89 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]90 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
91 <li><a href="#undefvalues">Undefined Values</a></li>
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]92 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]93 <li><a href="#constantexprs">Constant Expressions</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]94 </ol>
95 </li>
96 <li><a href="#othervalues">Other Values</a>
97 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]98 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]99 <li><a href="#metadata">Metadata Nodes and Metadata Strings</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]100 </ol>
101 </li>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]102 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
103 <ol>
104 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]105 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
106 Global Variable</a></li>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]107 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
108 Global Variable</a></li>
109 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
110 Global Variable</a></li>
111 </ol>
112 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]113 <li><a href="#instref">Instruction Reference</a>
114 <ol>
115 <li><a href="#terminators">Terminator Instructions</a>
116 <ol>
117 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
118 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
119 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]120 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]121 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
122 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
123 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
124 </ol>
125 </li>
126 <li><a href="#binaryops">Binary Operations</a>
127 <ol>
128 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]129 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]130 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]131 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]132 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]133 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]134 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
135 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
136 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
137 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
138 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
139 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
140 </ol>
141 </li>
142 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
143 <ol>
144 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
145 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
146 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
147 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
148 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
149 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
150 </ol>
151 </li>
152 <li><a href="#vectorops">Vector Operations</a>
153 <ol>
154 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
155 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
156 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
157 </ol>
158 </li>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]159 <li><a href="#aggregateops">Aggregate Operations</a>
160 <ol>
161 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
162 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
163 </ol>
164 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]165 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
166 <ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]167 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
168 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
169 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
170 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
171 </ol>
172 </li>
173 <li><a href="#convertops">Conversion Operations</a>
174 <ol>
175 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
176 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
177 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
178 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
179 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
180 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
181 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
182 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
183 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
184 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
185 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
186 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
187 </ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]188 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]189 <li><a href="#otherops">Other Operations</a>
190 <ol>
191 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
192 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
193 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
194 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
195 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
196 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
197 </ol>
198 </li>
199 </ol>
200 </li>
201 <li><a href="#intrinsics">Intrinsic Functions</a>
202 <ol>
203 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
204 <ol>
205 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
206 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
207 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
208 </ol>
209 </li>
210 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
211 <ol>
212 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
213 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
214 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
215 </ol>
216 </li>
217 <li><a href="#int_codegen">Code Generator Intrinsics</a>
218 <ol>
219 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
220 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
221 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
222 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
223 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
224 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
225 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
226 </ol>
227 </li>
228 <li><a href="#int_libc">Standard C Library Intrinsics</a>
229 <ol>
230 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
231 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
232 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
233 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
234 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]235 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
236 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
237 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]238 </ol>
239 </li>
240 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
241 <ol>
242 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
243 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
244 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
245 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]246 </ol>
247 </li>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]248 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
249 <ol>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]250 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
251 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
252 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
253 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
254 <li><a href="#int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]255 <li><a href="#int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]256 </ol>
257 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]258 <li><a href="#int_debugger">Debugger intrinsics</a></li>
259 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]260 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]261 <ol>
262 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]263 </ol>
264 </li>
Bill Wendling9127adb2008-11-18 22:10:53 +0000[diff] [blame]265 <li><a href="#int_atomics">Atomic intrinsics</a>
266 <ol>
267 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
268 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
269 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
270 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
271 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
272 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
273 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
274 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
275 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
276 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
277 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
278 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
279 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
280 </ol>
281 </li>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]282 <li><a href="#int_memorymarkers">Memory Use Markers</a>
283 <ol>
284 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
285 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
286 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
287 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
288 </ol>
289 </li>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]290 <li><a href="#int_general">General intrinsics</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]291 <ol>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]292 <li><a href="#int_var_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]293 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]294 <li><a href="#int_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]295 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]296 <li><a href="#int_trap">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]297 '<tt>llvm.trap</tt>' Intrinsic</a></li>
298 <li><a href="#int_stackprotector">
299 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]300 <li><a href="#int_objectsize">
301 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]302 </ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]303 </li>
304 </ol>
305 </li>
306</ol>
307
308<div class="doc_author">
309 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
310 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
311</div>
312
313<!-- *********************************************************************** -->
314<div class="doc_section"> <a name="abstract">Abstract </a></div>
315<!-- *********************************************************************** -->
316
317<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]318
319<p>This document is a reference manual for the LLVM assembly language. LLVM is
320 a Static Single Assignment (SSA) based representation that provides type
321 safety, low-level operations, flexibility, and the capability of representing
322 'all' high-level languages cleanly. It is the common code representation
323 used throughout all phases of the LLVM compilation strategy.</p>
324
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]325</div>
326
327<!-- *********************************************************************** -->
328<div class="doc_section"> <a name="introduction">Introduction</a> </div>
329<!-- *********************************************************************** -->
330
331<div class="doc_text">
332
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]333<p>The LLVM code representation is designed to be used in three different forms:
334 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
335 for fast loading by a Just-In-Time compiler), and as a human readable
336 assembly language representation. This allows LLVM to provide a powerful
337 intermediate representation for efficient compiler transformations and
338 analysis, while providing a natural means to debug and visualize the
339 transformations. The three different forms of LLVM are all equivalent. This
340 document describes the human readable representation and notation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]341
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]342<p>The LLVM representation aims to be light-weight and low-level while being
343 expressive, typed, and extensible at the same time. It aims to be a
344 "universal IR" of sorts, by being at a low enough level that high-level ideas
345 may be cleanly mapped to it (similar to how microprocessors are "universal
346 IR's", allowing many source languages to be mapped to them). By providing
347 type information, LLVM can be used as the target of optimizations: for
348 example, through pointer analysis, it can be proven that a C automatic
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]349 variable is never accessed outside of the current function, allowing it to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]350 be promoted to a simple SSA value instead of a memory location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]351
352</div>
353
354<!-- _______________________________________________________________________ -->
355<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
356
357<div class="doc_text">
358
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]359<p>It is important to note that this document describes 'well formed' LLVM
360 assembly language. There is a difference between what the parser accepts and
361 what is considered 'well formed'. For example, the following instruction is
362 syntactically okay, but not well formed:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]363
364<div class="doc_code">
365<pre>
366%x = <a href="#i_add">add</a> i32 1, %x
367</pre>
368</div>
369
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]370<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
371 LLVM infrastructure provides a verification pass that may be used to verify
372 that an LLVM module is well formed. This pass is automatically run by the
373 parser after parsing input assembly and by the optimizer before it outputs
374 bitcode. The violations pointed out by the verifier pass indicate bugs in
375 transformation passes or input to the parser.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]376
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]377</div>
378
Chris Lattnera83fdc02007-10-03 17:34:29 +0000[diff] [blame]379<!-- Describe the typesetting conventions here. -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]380
381<!-- *********************************************************************** -->
382<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
383<!-- *********************************************************************** -->
384
385<div class="doc_text">
386
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]387<p>LLVM identifiers come in two basic types: global and local. Global
388 identifiers (functions, global variables) begin with the <tt>'@'</tt>
389 character. Local identifiers (register names, types) begin with
390 the <tt>'%'</tt> character. Additionally, there are three different formats
391 for identifiers, for different purposes:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]392
393<ol>
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]394 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]395 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
396 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
397 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
398 other characters in their names can be surrounded with quotes. Special
399 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
400 ASCII code for the character in hexadecimal. In this way, any character
401 can be used in a name value, even quotes themselves.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]402
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]403 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]404 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]405
406 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]407 constants</a>, below.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]408</ol>
409
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]410<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]411 don't need to worry about name clashes with reserved words, and the set of
412 reserved words may be expanded in the future without penalty. Additionally,
413 unnamed identifiers allow a compiler to quickly come up with a temporary
414 variable without having to avoid symbol table conflicts.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]415
416<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]417 languages. There are keywords for different opcodes
418 ('<tt><a href="#i_add">add</a></tt>',
419 '<tt><a href="#i_bitcast">bitcast</a></tt>',
420 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
421 ('<tt><a href="#t_void">void</a></tt>',
422 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
423 reserved words cannot conflict with variable names, because none of them
424 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]425
426<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]427 '<tt>%X</tt>' by 8:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]428
429<p>The easy way:</p>
430
431<div class="doc_code">
432<pre>
433%result = <a href="#i_mul">mul</a> i32 %X, 8
434</pre>
435</div>
436
437<p>After strength reduction:</p>
438
439<div class="doc_code">
440<pre>
441%result = <a href="#i_shl">shl</a> i32 %X, i8 3
442</pre>
443</div>
444
445<p>And the hard way:</p>
446
447<div class="doc_code">
448<pre>
Gabor Greifc0ea7672009-10-28 13:05:07 +0000[diff] [blame]449%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
450%1 = <a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]451%result = <a href="#i_add">add</a> i32 %1, %1
452</pre>
453</div>
454
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]455<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
456 lexical features of LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]457
458<ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]459 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]460 line.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]461
462 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]463 assigned to a named value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]464
465 <li>Unnamed temporaries are numbered sequentially</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]466</ol>
467
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]468<p>It also shows a convention that we follow in this document. When
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]469 demonstrating instructions, we will follow an instruction with a comment that
470 defines the type and name of value produced. Comments are shown in italic
471 text.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]472
473</div>
474
475<!-- *********************************************************************** -->
476<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
477<!-- *********************************************************************** -->
478
479<!-- ======================================================================= -->
480<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
481</div>
482
483<div class="doc_text">
484
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]485<p>LLVM programs are composed of "Module"s, each of which is a translation unit
486 of the input programs. Each module consists of functions, global variables,
487 and symbol table entries. Modules may be combined together with the LLVM
488 linker, which merges function (and global variable) definitions, resolves
489 forward declarations, and merges symbol table entries. Here is an example of
490 the "hello world" module:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]491
492<div class="doc_code">
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]493<pre>
494<i>; Declare the string constant as a global constant.</i>
495<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]496
497<i>; External declaration of the puts function</i>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]498<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]499
500<i>; Definition of main function</i>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]501define i32 @main() { <i>; i32()* </i>
502 <i>; Convert [13 x i8]* to i8 *...</i>
503 %cast210 = <a href="#i_getelementptr">getelementptr</a> [13 x i8]* @.LC0, i64 0, i64 0 <i>; i8 *</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]504
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]505 <i>; Call puts function to write out the string to stdout.</i>
506 <a href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]507 <a href="#i_ret">ret</a> i32 0<br>}
508
509<i>; Named metadata</i>
510!1 = metadata !{i32 41}
511!foo = !{!1, null}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]512</pre>
513</div>
514
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]515<p>This example is made up of a <a href="#globalvars">global variable</a> named
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]516 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]517 a <a href="#functionstructure">function definition</a> for
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]518 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
519 "<tt>foo"</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]520
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]521<p>In general, a module is made up of a list of global values, where both
522 functions and global variables are global values. Global values are
523 represented by a pointer to a memory location (in this case, a pointer to an
524 array of char, and a pointer to a function), and have one of the
525 following <a href="#linkage">linkage types</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]526
527</div>
528
529<!-- ======================================================================= -->
530<div class="doc_subsection">
531 <a name="linkage">Linkage Types</a>
532</div>
533
534<div class="doc_text">
535
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]536<p>All Global Variables and Functions have one of the following types of
537 linkage:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]538
539<dl>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]540 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]541 <dd>Global values with private linkage are only directly accessible by objects
542 in the current module. In particular, linking code into a module with an
543 private global value may cause the private to be renamed as necessary to
544 avoid collisions. Because the symbol is private to the module, all
545 references can be updated. This doesn't show up in any symbol table in the
546 object file.</dd>
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000[diff] [blame]547
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]548 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]549 <dd>Similar to private, but the symbol is passed through the assembler and
Chris Lattner06c1ecc2009-08-24 04:32:16 +0000[diff] [blame]550 removed by the linker after evaluation. Note that (unlike private
551 symbols) linker_private symbols are subject to coalescing by the linker:
552 weak symbols get merged and redefinitions are rejected. However, unlike
553 normal strong symbols, they are removed by the linker from the final
554 linked image (executable or dynamic library).</dd>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]555
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]556 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]557 <dd>Similar to private, but the value shows as a local symbol
558 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
559 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]560
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]561 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]562 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]563 into the object file corresponding to the LLVM module. They exist to
564 allow inlining and other optimizations to take place given knowledge of
565 the definition of the global, which is known to be somewhere outside the
566 module. Globals with <tt>available_externally</tt> linkage are allowed to
567 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
568 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]569
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]570 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]571 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattnerd16c5512010-01-09 19:15:14 +0000[diff] [blame]572 the same name when linkage occurs. This can be used to implement
573 some forms of inline functions, templates, or other code which must be
574 generated in each translation unit that uses it, but where the body may
575 be overridden with a more definitive definition later. Unreferenced
576 <tt>linkonce</tt> globals are allowed to be discarded. Note that
577 <tt>linkonce</tt> linkage does not actually allow the optimizer to
578 inline the body of this function into callers because it doesn't know if
579 this definition of the function is the definitive definition within the
580 program or whether it will be overridden by a stronger definition.
581 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
582 linkage.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]583
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]584 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]585 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
586 <tt>linkonce</tt> linkage, except that unreferenced globals with
587 <tt>weak</tt> linkage may not be discarded. This is used for globals that
588 are declared "weak" in C source code.</dd>
589
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]590 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]591 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
592 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
593 global scope.
594 Symbols with "<tt>common</tt>" linkage are merged in the same way as
595 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattner83c4a712009-08-05 05:41:44 +0000[diff] [blame]596 <tt>common</tt> symbols may not have an explicit section,
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]597 must have a zero initializer, and may not be marked '<a
Chris Lattner83c4a712009-08-05 05:41:44 +0000[diff] [blame]598 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
599 have common linkage.</dd>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]600
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]601
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]602 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]603 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]604 pointer to array type. When two global variables with appending linkage
605 are linked together, the two global arrays are appended together. This is
606 the LLVM, typesafe, equivalent of having the system linker append together
607 "sections" with identical names when .o files are linked.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]608
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]609 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]610 <dd>The semantics of this linkage follow the ELF object file model: the symbol
611 is weak until linked, if not linked, the symbol becomes null instead of
612 being an undefined reference.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]613
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]614 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
615 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]616 <dd>Some languages allow differing globals to be merged, such as two functions
617 with different semantics. Other languages, such as <tt>C++</tt>, ensure
618 that only equivalent globals are ever merged (the "one definition rule" -
619 "ODR"). Such languages can use the <tt>linkonce_odr</tt>
620 and <tt>weak_odr</tt> linkage types to indicate that the global will only
621 be merged with equivalent globals. These linkage types are otherwise the
622 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]623
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]624 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]625 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]626 visible, meaning that it participates in linkage and can be used to
627 resolve external symbol references.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]628</dl>
629
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]630<p>The next two types of linkage are targeted for Microsoft Windows platform
631 only. They are designed to support importing (exporting) symbols from (to)
632 DLLs (Dynamic Link Libraries).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]633
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]634<dl>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]635 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]636 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]637 or variable via a global pointer to a pointer that is set up by the DLL
638 exporting the symbol. On Microsoft Windows targets, the pointer name is
639 formed by combining <code>__imp_</code> and the function or variable
640 name.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]641
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]642 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]643 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]644 pointer to a pointer in a DLL, so that it can be referenced with the
645 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
646 name is formed by combining <code>__imp_</code> and the function or
647 variable name.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]648</dl>
649
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]650<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
651 another module defined a "<tt>.LC0</tt>" variable and was linked with this
652 one, one of the two would be renamed, preventing a collision. Since
653 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
654 declarations), they are accessible outside of the current module.</p>
655
656<p>It is illegal for a function <i>declaration</i> to have any linkage type
657 other than "externally visible", <tt>dllimport</tt>
658 or <tt>extern_weak</tt>.</p>
659
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]660<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]661 or <tt>weak_odr</tt> linkages.</p>
662
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]663</div>
664
665<!-- ======================================================================= -->
666<div class="doc_subsection">
667 <a name="callingconv">Calling Conventions</a>
668</div>
669
670<div class="doc_text">
671
672<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]673 and <a href="#i_invoke">invokes</a> can all have an optional calling
674 convention specified for the call. The calling convention of any pair of
675 dynamic caller/callee must match, or the behavior of the program is
676 undefined. The following calling conventions are supported by LLVM, and more
677 may be added in the future:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]678
679<dl>
680 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]681 <dd>This calling convention (the default if no other calling convention is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]682 specified) matches the target C calling conventions. This calling
683 convention supports varargs function calls and tolerates some mismatch in
684 the declared prototype and implemented declaration of the function (as
685 does normal C).</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]686
687 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]688 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]689 (e.g. by passing things in registers). This calling convention allows the
690 target to use whatever tricks it wants to produce fast code for the
691 target, without having to conform to an externally specified ABI
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]692 (Application Binary Interface).
693 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
694 when this convention is used.</a> This calling convention does not
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]695 support varargs and requires the prototype of all callees to exactly match
696 the prototype of the function definition.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]697
698 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]699 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]700 as possible under the assumption that the call is not commonly executed.
701 As such, these calls often preserve all registers so that the call does
702 not break any live ranges in the caller side. This calling convention
703 does not support varargs and requires the prototype of all callees to
704 exactly match the prototype of the function definition.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]705
706 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]707 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]708 target-specific calling conventions to be used. Target specific calling
709 conventions start at 64.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]710</dl>
711
712<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]713 support Pascal conventions or any other well-known target-independent
714 convention.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]715
716</div>
717
718<!-- ======================================================================= -->
719<div class="doc_subsection">
720 <a name="visibility">Visibility Styles</a>
721</div>
722
723<div class="doc_text">
724
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]725<p>All Global Variables and Functions have one of the following visibility
726 styles:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]727
728<dl>
729 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]730 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]731 that the declaration is visible to other modules and, in shared libraries,
732 means that the declared entity may be overridden. On Darwin, default
733 visibility means that the declaration is visible to other modules. Default
734 visibility corresponds to "external linkage" in the language.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]735
736 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]737 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]738 object if they are in the same shared object. Usually, hidden visibility
739 indicates that the symbol will not be placed into the dynamic symbol
740 table, so no other module (executable or shared library) can reference it
741 directly.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]742
743 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]744 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]745 the dynamic symbol table, but that references within the defining module
746 will bind to the local symbol. That is, the symbol cannot be overridden by
747 another module.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]748</dl>
749
750</div>
751
752<!-- ======================================================================= -->
753<div class="doc_subsection">
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]754 <a name="namedtypes">Named Types</a>
755</div>
756
757<div class="doc_text">
758
759<p>LLVM IR allows you to specify name aliases for certain types. This can make
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]760 it easier to read the IR and make the IR more condensed (particularly when
761 recursive types are involved). An example of a name specification is:</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]762
763<div class="doc_code">
764<pre>
765%mytype = type { %mytype*, i32 }
766</pre>
767</div>
768
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]769<p>You may give a name to any <a href="#typesystem">type</a> except
770 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
771 is expected with the syntax "%mytype".</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]772
773<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]774 and that you can therefore specify multiple names for the same type. This
775 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
776 uses structural typing, the name is not part of the type. When printing out
777 LLVM IR, the printer will pick <em>one name</em> to render all types of a
778 particular shape. This means that if you have code where two different
779 source types end up having the same LLVM type, that the dumper will sometimes
780 print the "wrong" or unexpected type. This is an important design point and
781 isn't going to change.</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]782
783</div>
784
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]785<!-- ======================================================================= -->
786<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]787 <a name="globalvars">Global Variables</a>
788</div>
789
790<div class="doc_text">
791
792<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]793 instead of run-time. Global variables may optionally be initialized, may
794 have an explicit section to be placed in, and may have an optional explicit
795 alignment specified. A variable may be defined as "thread_local", which
796 means that it will not be shared by threads (each thread will have a
797 separated copy of the variable). A variable may be defined as a global
798 "constant," which indicates that the contents of the variable
799 will <b>never</b> be modified (enabling better optimization, allowing the
800 global data to be placed in the read-only section of an executable, etc).
801 Note that variables that need runtime initialization cannot be marked
802 "constant" as there is a store to the variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]803
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]804<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
805 constant, even if the final definition of the global is not. This capability
806 can be used to enable slightly better optimization of the program, but
807 requires the language definition to guarantee that optimizations based on the
808 'constantness' are valid for the translation units that do not include the
809 definition.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]810
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]811<p>As SSA values, global variables define pointer values that are in scope
812 (i.e. they dominate) all basic blocks in the program. Global variables
813 always define a pointer to their "content" type because they describe a
814 region of memory, and all memory objects in LLVM are accessed through
815 pointers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]816
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]817<p>A global variable may be declared to reside in a target-specific numbered
818 address space. For targets that support them, address spaces may affect how
819 optimizations are performed and/or what target instructions are used to
820 access the variable. The default address space is zero. The address space
821 qualifier must precede any other attributes.</p>
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]822
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]823<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]824 supports it, it will emit globals to the section specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]825
826<p>An explicit alignment may be specified for a global. If not present, or if
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]827 the alignment is set to zero, the alignment of the global is set by the
828 target to whatever it feels convenient. If an explicit alignment is
829 specified, the global is forced to have at least that much alignment. All
830 alignments must be a power of 2.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]831
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]832<p>For example, the following defines a global in a numbered address space with
833 an initializer, section, and alignment:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]834
835<div class="doc_code">
836<pre>
Dan Gohman21ef02c2009-01-11 00:40:00 +0000[diff] [blame]837@G = addrspace(5) constant float 1.0, section "foo", align 4
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]838</pre>
839</div>
840
841</div>
842
843
844<!-- ======================================================================= -->
845<div class="doc_subsection">
846 <a name="functionstructure">Functions</a>
847</div>
848
849<div class="doc_text">
850
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]851<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]852 optional <a href="#linkage">linkage type</a>, an optional
853 <a href="#visibility">visibility style</a>, an optional
854 <a href="#callingconv">calling convention</a>, a return type, an optional
855 <a href="#paramattrs">parameter attribute</a> for the return type, a function
856 name, a (possibly empty) argument list (each with optional
857 <a href="#paramattrs">parameter attributes</a>), optional
858 <a href="#fnattrs">function attributes</a>, an optional section, an optional
859 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
860 curly brace, a list of basic blocks, and a closing curly brace.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]861
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]862<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
863 optional <a href="#linkage">linkage type</a>, an optional
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]864 <a href="#visibility">visibility style</a>, an optional
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]865 <a href="#callingconv">calling convention</a>, a return type, an optional
866 <a href="#paramattrs">parameter attribute</a> for the return type, a function
867 name, a possibly empty list of arguments, an optional alignment, and an
868 optional <a href="#gc">garbage collector name</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]869
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]870<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]871 (Control Flow Graph) for the function. Each basic block may optionally start
872 with a label (giving the basic block a symbol table entry), contains a list
873 of instructions, and ends with a <a href="#terminators">terminator</a>
874 instruction (such as a branch or function return).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]875
876<p>The first basic block in a function is special in two ways: it is immediately
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]877 executed on entrance to the function, and it is not allowed to have
878 predecessor basic blocks (i.e. there can not be any branches to the entry
879 block of a function). Because the block can have no predecessors, it also
880 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]881
882<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]883 supports it, it will emit functions to the section specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]884
885<p>An explicit alignment may be specified for a function. If not present, or if
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]886 the alignment is set to zero, the alignment of the function is set by the
887 target to whatever it feels convenient. If an explicit alignment is
888 specified, the function is forced to have at least that much alignment. All
889 alignments must be a power of 2.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]890
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]891<h5>Syntax:</h5>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]892<div class="doc_code">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]893<pre>
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]894define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]895 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
896 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
897 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
898 [<a href="#gc">gc</a>] { ... }
899</pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]900</div>
901
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]902</div>
903
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]904<!-- ======================================================================= -->
905<div class="doc_subsection">
906 <a name="aliasstructure">Aliases</a>
907</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]908
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]909<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]910
911<p>Aliases act as "second name" for the aliasee value (which can be either
912 function, global variable, another alias or bitcast of global value). Aliases
913 may have an optional <a href="#linkage">linkage type</a>, and an
914 optional <a href="#visibility">visibility style</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]915
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]916<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]917<div class="doc_code">
918<pre>
Duncan Sandsd7bfabf2008-09-12 20:48:21 +0000[diff] [blame]919@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]920</pre>
921</div>
922
923</div>
924
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]925<!-- ======================================================================= -->
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]926<div class="doc_subsection">
927 <a name="namedmetadatastructure">Named Metadata</a>
928</div>
929
930<div class="doc_text">
931
Chris Lattnerd0d96292010-01-15 21:50:19 +0000[diff] [blame]932<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
933 nodes</a> (but not metadata strings) and null are the only valid operands for
934 a named metadata.</p>
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]935
936<h5>Syntax:</h5>
937<div class="doc_code">
938<pre>
939!1 = metadata !{metadata !"one"}
940!name = !{null, !1}
941</pre>
942</div>
943
944</div>
945
946<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]947<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]948
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]949<div class="doc_text">
950
951<p>The return type and each parameter of a function type may have a set of
952 <i>parameter attributes</i> associated with them. Parameter attributes are
953 used to communicate additional information about the result or parameters of
954 a function. Parameter attributes are considered to be part of the function,
955 not of the function type, so functions with different parameter attributes
956 can have the same function type.</p>
957
958<p>Parameter attributes are simple keywords that follow the type specified. If
959 multiple parameter attributes are needed, they are space separated. For
960 example:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]961
962<div class="doc_code">
963<pre>
Nick Lewycky3022a742009-02-15 23:06:14 +0000[diff] [blame]964declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]965declare i32 @atoi(i8 zeroext)
966declare signext i8 @returns_signed_char()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]967</pre>
968</div>
969
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]970<p>Note that any attributes for the function result (<tt>nounwind</tt>,
971 <tt>readonly</tt>) come immediately after the argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]972
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]973<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]974
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]975<dl>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]976 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]977 <dd>This indicates to the code generator that the parameter or return value
978 should be zero-extended to a 32-bit value by the caller (for a parameter)
979 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]980
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]981 <dt><tt><b>signext</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]982 <dd>This indicates to the code generator that the parameter or return value
983 should be sign-extended to a 32-bit value by the caller (for a parameter)
984 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]985
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]986 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]987 <dd>This indicates that this parameter or return value should be treated in a
988 special target-dependent fashion during while emitting code for a function
989 call or return (usually, by putting it in a register as opposed to memory,
990 though some targets use it to distinguish between two different kinds of
991 registers). Use of this attribute is target-specific.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]992
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]993 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]994 <dd>This indicates that the pointer parameter should really be passed by value
995 to the function. The attribute implies that a hidden copy of the pointee
996 is made between the caller and the callee, so the callee is unable to
997 modify the value in the callee. This attribute is only valid on LLVM
998 pointer arguments. It is generally used to pass structs and arrays by
999 value, but is also valid on pointers to scalars. The copy is considered
1000 to belong to the caller not the callee (for example,
1001 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1002 <tt>byval</tt> parameters). This is not a valid attribute for return
1003 values. The byval attribute also supports specifying an alignment with
1004 the align attribute. This has a target-specific effect on the code
1005 generator that usually indicates a desired alignment for the synthesized
1006 stack slot.</dd>
1007
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1008 <dt><tt><b>sret</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1009 <dd>This indicates that the pointer parameter specifies the address of a
1010 structure that is the return value of the function in the source program.
1011 This pointer must be guaranteed by the caller to be valid: loads and
1012 stores to the structure may be assumed by the callee to not to trap. This
1013 may only be applied to the first parameter. This is not a valid attribute
1014 for return values. </dd>
1015
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1016 <dt><tt><b>noalias</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1017 <dd>This indicates that the pointer does not alias any global or any other
1018 parameter. The caller is responsible for ensuring that this is the
1019 case. On a function return value, <tt>noalias</tt> additionally indicates
1020 that the pointer does not alias any other pointers visible to the
1021 caller. For further details, please see the discussion of the NoAlias
1022 response in
1023 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
1024 analysis</a>.</dd>
1025
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1026 <dt><tt><b>nocapture</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1027 <dd>This indicates that the callee does not make any copies of the pointer
1028 that outlive the callee itself. This is not a valid attribute for return
1029 values.</dd>
1030
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1031 <dt><tt><b>nest</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1032 <dd>This indicates that the pointer parameter can be excised using the
1033 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1034 attribute for return values.</dd>
1035</dl>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1036
1037</div>
1038
1039<!-- ======================================================================= -->
1040<div class="doc_subsection">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1041 <a name="gc">Garbage Collector Names</a>
1042</div>
1043
1044<div class="doc_text">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1045
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1046<p>Each function may specify a garbage collector name, which is simply a
1047 string:</p>
1048
1049<div class="doc_code">
1050<pre>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1051define void @f() gc "name" { ... }
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1052</pre>
1053</div>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1054
1055<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1056 collector which will cause the compiler to alter its output in order to
1057 support the named garbage collection algorithm.</p>
1058
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1059</div>
1060
1061<!-- ======================================================================= -->
1062<div class="doc_subsection">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1063 <a name="fnattrs">Function Attributes</a>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1064</div>
1065
1066<div class="doc_text">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1067
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1068<p>Function attributes are set to communicate additional information about a
1069 function. Function attributes are considered to be part of the function, not
1070 of the function type, so functions with different parameter attributes can
1071 have the same function type.</p>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1072
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1073<p>Function attributes are simple keywords that follow the type specified. If
1074 multiple attributes are needed, they are space separated. For example:</p>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1075
1076<div class="doc_code">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1077<pre>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1078define void @f() noinline { ... }
1079define void @f() alwaysinline { ... }
1080define void @f() alwaysinline optsize { ... }
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1081define void @f() optsize { ... }
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1082</pre>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1083</div>
1084
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1085<dl>
Charles Davisfaa8f752010-02-12 00:31:15 +0000[diff] [blame]1086 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1087 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1088 the backend should forcibly align the stack pointer. Specify the
1089 desired alignment, which must be a power of two, in parentheses.
1090
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1091 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1092 <dd>This attribute indicates that the inliner should attempt to inline this
1093 function into callers whenever possible, ignoring any active inlining size
1094 threshold for this caller.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1095
Jakob Stoklund Olesen77180732010-02-06 01:16:28 +0000[diff] [blame]1096 <dt><tt><b>inlinehint</b></tt></dt>
1097 <dd>This attribute indicates that the source code contained a hint that inlining
1098 this function is desirable (such as the "inline" keyword in C/C++). It
1099 is just a hint; it imposes no requirements on the inliner.</dd>
1100
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1101 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1102 <dd>This attribute indicates that the inliner should never inline this
1103 function in any situation. This attribute may not be used together with
1104 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1105
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1106 <dt><tt><b>optsize</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1107 <dd>This attribute suggests that optimization passes and code generator passes
1108 make choices that keep the code size of this function low, and otherwise
1109 do optimizations specifically to reduce code size.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1110
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1111 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1112 <dd>This function attribute indicates that the function never returns
1113 normally. This produces undefined behavior at runtime if the function
1114 ever does dynamically return.</dd>
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1115
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1116 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1117 <dd>This function attribute indicates that the function never returns with an
1118 unwind or exceptional control flow. If the function does unwind, its
1119 runtime behavior is undefined.</dd>
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1120
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1121 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1122 <dd>This attribute indicates that the function computes its result (or decides
1123 to unwind an exception) based strictly on its arguments, without
1124 dereferencing any pointer arguments or otherwise accessing any mutable
1125 state (e.g. memory, control registers, etc) visible to caller functions.
1126 It does not write through any pointer arguments
1127 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1128 changes any state visible to callers. This means that it cannot unwind
1129 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1130 could use the <tt>unwind</tt> instruction.</dd>
Devang Patela2f9f412009-06-12 19:45:19 +0000[diff] [blame]1131
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1132 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1133 <dd>This attribute indicates that the function does not write through any
1134 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1135 arguments) or otherwise modify any state (e.g. memory, control registers,
1136 etc) visible to caller functions. It may dereference pointer arguments
1137 and read state that may be set in the caller. A readonly function always
1138 returns the same value (or unwinds an exception identically) when called
1139 with the same set of arguments and global state. It cannot unwind an
1140 exception by calling the <tt>C++</tt> exception throwing methods, but may
1141 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovedd7d112009-07-17 18:07:26 +0000[diff] [blame]1142
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1143 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1144 <dd>This attribute indicates that the function should emit a stack smashing
1145 protector. It is in the form of a "canary"&mdash;a random value placed on
1146 the stack before the local variables that's checked upon return from the
1147 function to see if it has been overwritten. A heuristic is used to
1148 determine if a function needs stack protectors or not.<br>
1149<br>
1150 If a function that has an <tt>ssp</tt> attribute is inlined into a
1151 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1152 function will have an <tt>ssp</tt> attribute.</dd>
1153
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1154 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1155 <dd>This attribute indicates that the function should <em>always</em> emit a
1156 stack smashing protector. This overrides
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1157 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1158<br>
1159 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1160 function that doesn't have an <tt>sspreq</tt> attribute or which has
1161 an <tt>ssp</tt> attribute, then the resulting function will have
1162 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1163
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1164 <dt><tt><b>noredzone</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1165 <dd>This attribute indicates that the code generator should not use a red
1166 zone, even if the target-specific ABI normally permits it.</dd>
1167
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1168 <dt><tt><b>noimplicitfloat</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1169 <dd>This attributes disables implicit floating point instructions.</dd>
1170
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1171 <dt><tt><b>naked</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1172 <dd>This attribute disables prologue / epilogue emission for the function.
1173 This can have very system-specific consequences.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1174</dl>
1175
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1176</div>
1177
1178<!-- ======================================================================= -->
1179<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1180 <a name="moduleasm">Module-Level Inline Assembly</a>
1181</div>
1182
1183<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1184
1185<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1186 the GCC "file scope inline asm" blocks. These blocks are internally
1187 concatenated by LLVM and treated as a single unit, but may be separated in
1188 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1189
1190<div class="doc_code">
1191<pre>
1192module asm "inline asm code goes here"
1193module asm "more can go here"
1194</pre>
1195</div>
1196
1197<p>The strings can contain any character by escaping non-printable characters.
1198 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1199 for the number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1200
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1201<p>The inline asm code is simply printed to the machine code .s file when
1202 assembly code is generated.</p>
1203
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1204</div>
1205
1206<!-- ======================================================================= -->
1207<div class="doc_subsection">
1208 <a name="datalayout">Data Layout</a>
1209</div>
1210
1211<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1212
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1213<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1214 data is to be laid out in memory. The syntax for the data layout is
1215 simply:</p>
1216
1217<div class="doc_code">
1218<pre>
1219target datalayout = "<i>layout specification</i>"
1220</pre>
1221</div>
1222
1223<p>The <i>layout specification</i> consists of a list of specifications
1224 separated by the minus sign character ('-'). Each specification starts with
1225 a letter and may include other information after the letter to define some
1226 aspect of the data layout. The specifications accepted are as follows:</p>
1227
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1228<dl>
1229 <dt><tt>E</tt></dt>
1230 <dd>Specifies that the target lays out data in big-endian form. That is, the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1231 bits with the most significance have the lowest address location.</dd>
1232
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1233 <dt><tt>e</tt></dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1234 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1235 the bits with the least significance have the lowest address
1236 location.</dd>
1237
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1238 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1239 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1240 <i>preferred</i> alignments. All sizes are in bits. Specifying
1241 the <i>pref</i> alignment is optional. If omitted, the
1242 preceding <tt>:</tt> should be omitted too.</dd>
1243
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1244 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1245 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1246 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1247
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1248 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1249 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1250 <i>size</i>.</dd>
1251
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1252 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1253 <dd>This specifies the alignment for a floating point type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1254 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1255 (double).</dd>
1256
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1257 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1258 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1259 <i>size</i>.</dd>
1260
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1261 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1262 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1263 <i>size</i>.</dd>
Chris Lattnerece41802009-11-07 09:35:34 +0000[diff] [blame]1264
1265 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1266 <dd>This specifies a set of native integer widths for the target CPU
1267 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1268 "n32:64" for PowerPC 64, or "n8:16:32:64" for X86-64. Elements of
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1269 this set are considered to support most general arithmetic
Chris Lattnerece41802009-11-07 09:35:34 +0000[diff] [blame]1270 operations efficiently.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1271</dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1272
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1273<p>When constructing the data layout for a given target, LLVM starts with a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1274 default set of specifications which are then (possibly) overriden by the
1275 specifications in the <tt>datalayout</tt> keyword. The default specifications
1276 are given in this list:</p>
1277
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1278<ul>
1279 <li><tt>E</tt> - big endian</li>
Dan Gohmane78194f2010-02-23 02:44:03 +0000[diff] [blame]1280 <li><tt>p:64:64:64</tt> - 64-bit pointers with 64-bit alignment</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1281 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1282 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1283 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1284 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1285 <li><tt>i64:32:64</tt> - i64 has ABI alignment of 32-bits but preferred
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1286 alignment of 64-bits</li>
1287 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1288 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1289 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1290 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1291 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1292 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1293</ul>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1294
1295<p>When LLVM is determining the alignment for a given type, it uses the
1296 following rules:</p>
1297
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1298<ol>
1299 <li>If the type sought is an exact match for one of the specifications, that
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1300 specification is used.</li>
1301
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1302 <li>If no match is found, and the type sought is an integer type, then the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1303 smallest integer type that is larger than the bitwidth of the sought type
1304 is used. If none of the specifications are larger than the bitwidth then
1305 the the largest integer type is used. For example, given the default
1306 specifications above, the i7 type will use the alignment of i8 (next
1307 largest) while both i65 and i256 will use the alignment of i64 (largest
1308 specified).</li>
1309
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1310 <li>If no match is found, and the type sought is a vector type, then the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1311 largest vector type that is smaller than the sought vector type will be
1312 used as a fall back. This happens because &lt;128 x double&gt; can be
1313 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1314</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1315
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1316</div>
1317
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1318<!-- ======================================================================= -->
1319<div class="doc_subsection">
1320 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1321</div>
1322
1323<div class="doc_text">
1324
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1325<p>Any memory access must be done through a pointer value associated
Andreas Bolka23bece42009-07-27 20:37:10 +0000[diff] [blame]1326with an address range of the memory access, otherwise the behavior
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1327is undefined. Pointer values are associated with address ranges
1328according to the following rules:</p>
1329
1330<ul>
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1331 <li>A pointer value formed from a
1332 <tt><a href="#i_getelementptr">getelementptr</a></tt> instruction
1333 is associated with the addresses associated with the first operand
1334 of the <tt>getelementptr</tt>.</li>
1335 <li>An address of a global variable is associated with the address
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1336 range of the variable's storage.</li>
1337 <li>The result value of an allocation instruction is associated with
1338 the address range of the allocated storage.</li>
1339 <li>A null pointer in the default address-space is associated with
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1340 no address.</li>
1341 <li>A pointer value formed by an
1342 <tt><a href="#i_inttoptr">inttoptr</a></tt> is associated with all
1343 address ranges of all pointer values that contribute (directly or
1344 indirectly) to the computation of the pointer's value.</li>
1345 <li>The result value of a
1346 <tt><a href="#i_bitcast">bitcast</a></tt> is associated with all
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1347 addresses associated with the operand of the <tt>bitcast</tt>.</li>
1348 <li>An integer constant other than zero or a pointer value returned
1349 from a function not defined within LLVM may be associated with address
1350 ranges allocated through mechanisms other than those provided by
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1351 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1352 allocated by mechanisms provided by LLVM.</li>
1353 </ul>
1354
1355<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1356<tt><a href="#i_load">load</a></tt> merely indicates the size and
1357alignment of the memory from which to load, as well as the
1358interpretation of the value. The first operand of a
1359<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1360and alignment of the store.</p>
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1361
1362<p>Consequently, type-based alias analysis, aka TBAA, aka
1363<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1364LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1365additional information which specialized optimization passes may use
1366to implement type-based alias analysis.</p>
1367
1368</div>
1369
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1370<!-- *********************************************************************** -->
1371<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1372<!-- *********************************************************************** -->
1373
1374<div class="doc_text">
1375
1376<p>The LLVM type system is one of the most important features of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1377 intermediate representation. Being typed enables a number of optimizations
1378 to be performed on the intermediate representation directly, without having
1379 to do extra analyses on the side before the transformation. A strong type
1380 system makes it easier to read the generated code and enables novel analyses
1381 and transformations that are not feasible to perform on normal three address
1382 code representations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1383
1384</div>
1385
1386<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1387<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1388Classifications</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1389
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1390<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1391
1392<p>The types fall into a few useful classifications:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1393
1394<table border="1" cellspacing="0" cellpadding="4">
1395 <tbody>
1396 <tr><th>Classification</th><th>Types</th></tr>
1397 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1398 <td><a href="#t_integer">integer</a></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1399 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
1400 </tr>
1401 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1402 <td><a href="#t_floating">floating point</a></td>
1403 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1404 </tr>
1405 <tr>
1406 <td><a name="t_firstclass">first class</a></td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1407 <td><a href="#t_integer">integer</a>,
1408 <a href="#t_floating">floating point</a>,
1409 <a href="#t_pointer">pointer</a>,
Dan Gohmanf6237db2008-06-18 18:42:13 +0000[diff] [blame]1410 <a href="#t_vector">vector</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1411 <a href="#t_struct">structure</a>,
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1412 <a href="#t_union">union</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1413 <a href="#t_array">array</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1414 <a href="#t_label">label</a>,
1415 <a href="#t_metadata">metadata</a>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1416 </td>
1417 </tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1418 <tr>
1419 <td><a href="#t_primitive">primitive</a></td>
1420 <td><a href="#t_label">label</a>,
1421 <a href="#t_void">void</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1422 <a href="#t_floating">floating point</a>,
1423 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1424 </tr>
1425 <tr>
1426 <td><a href="#t_derived">derived</a></td>
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1427 <td><a href="#t_array">array</a>,
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1428 <a href="#t_function">function</a>,
1429 <a href="#t_pointer">pointer</a>,
1430 <a href="#t_struct">structure</a>,
1431 <a href="#t_pstruct">packed structure</a>,
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1432 <a href="#t_union">union</a>,
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1433 <a href="#t_vector">vector</a>,
1434 <a href="#t_opaque">opaque</a>.
Dan Gohman032ba852008-10-14 16:32:04 +0000[diff] [blame]1435 </td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1436 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1437 </tbody>
1438</table>
1439
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1440<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1441 important. Values of these types are the only ones which can be produced by
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1442 instructions.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1443
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1444</div>
1445
1446<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1447<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1448
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1449<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1450
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1451<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1452 system.</p>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1453
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1454</div>
1455
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1456<!-- _______________________________________________________________________ -->
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1457<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1458
1459<div class="doc_text">
1460
1461<h5>Overview:</h5>
1462<p>The integer type is a very simple type that simply specifies an arbitrary
1463 bit width for the integer type desired. Any bit width from 1 bit to
1464 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1465
1466<h5>Syntax:</h5>
1467<pre>
1468 iN
1469</pre>
1470
1471<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1472 value.</p>
1473
1474<h5>Examples:</h5>
1475<table class="layout">
1476 <tr class="layout">
1477 <td class="left"><tt>i1</tt></td>
1478 <td class="left">a single-bit integer.</td>
1479 </tr>
1480 <tr class="layout">
1481 <td class="left"><tt>i32</tt></td>
1482 <td class="left">a 32-bit integer.</td>
1483 </tr>
1484 <tr class="layout">
1485 <td class="left"><tt>i1942652</tt></td>
1486 <td class="left">a really big integer of over 1 million bits.</td>
1487 </tr>
1488</table>
1489
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1490</div>
1491
1492<!-- _______________________________________________________________________ -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1493<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1494
1495<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1496
1497<table>
1498 <tbody>
1499 <tr><th>Type</th><th>Description</th></tr>
1500 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1501 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1502 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1503 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1504 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1505 </tbody>
1506</table>
1507
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1508</div>
1509
1510<!-- _______________________________________________________________________ -->
1511<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1512
1513<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1514
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1515<h5>Overview:</h5>
1516<p>The void type does not represent any value and has no size.</p>
1517
1518<h5>Syntax:</h5>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1519<pre>
1520 void
1521</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1522
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1523</div>
1524
1525<!-- _______________________________________________________________________ -->
1526<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1527
1528<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1529
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1530<h5>Overview:</h5>
1531<p>The label type represents code labels.</p>
1532
1533<h5>Syntax:</h5>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1534<pre>
1535 label
1536</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1537
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1538</div>
1539
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1540<!-- _______________________________________________________________________ -->
1541<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1542
1543<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1544
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1545<h5>Overview:</h5>
Nick Lewyckyeb021882009-09-27 23:27:42 +0000[diff] [blame]1546<p>The metadata type represents embedded metadata. No derived types may be
1547 created from metadata except for <a href="#t_function">function</a>
1548 arguments.
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1549
1550<h5>Syntax:</h5>
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1551<pre>
1552 metadata
1553</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1554
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1555</div>
1556
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1557
1558<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1559<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
1560
1561<div class="doc_text">
1562
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1563<p>The real power in LLVM comes from the derived types in the system. This is
1564 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1565 useful types. Each of these types contain one or more element types which
1566 may be a primitive type, or another derived type. For example, it is
1567 possible to have a two dimensional array, using an array as the element type
1568 of another array.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1569
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1570
1571</div>
1572
1573<!-- _______________________________________________________________________ -->
1574<div class="doc_subsubsection"> <a name="t_aggregate">Aggregate Types</a> </div>
1575
1576<div class="doc_text">
1577
1578<p>Aggregate Types are a subset of derived types that can contain multiple
1579 member types. <a href="#t_array">Arrays</a>,
1580 <a href="#t_struct">structs</a>, <a href="#t_vector">vectors</a> and
1581 <a href="#t_union">unions</a> are aggregate types.</p>
1582
1583</div>
1584
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1585</div>
1586
1587<!-- _______________________________________________________________________ -->
1588<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
1589
1590<div class="doc_text">
1591
1592<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1593<p>The array type is a very simple derived type that arranges elements
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1594 sequentially in memory. The array type requires a size (number of elements)
1595 and an underlying data type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1596
1597<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1598<pre>
1599 [&lt;# elements&gt; x &lt;elementtype&gt;]
1600</pre>
1601
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1602<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1603 be any type with a size.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1604
1605<h5>Examples:</h5>
1606<table class="layout">
1607 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1608 <td class="left"><tt>[40 x i32]</tt></td>
1609 <td class="left">Array of 40 32-bit integer values.</td>
1610 </tr>
1611 <tr class="layout">
1612 <td class="left"><tt>[41 x i32]</tt></td>
1613 <td class="left">Array of 41 32-bit integer values.</td>
1614 </tr>
1615 <tr class="layout">
1616 <td class="left"><tt>[4 x i8]</tt></td>
1617 <td class="left">Array of 4 8-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1618 </tr>
1619</table>
1620<p>Here are some examples of multidimensional arrays:</p>
1621<table class="layout">
1622 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1623 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1624 <td class="left">3x4 array of 32-bit integer values.</td>
1625 </tr>
1626 <tr class="layout">
1627 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1628 <td class="left">12x10 array of single precision floating point values.</td>
1629 </tr>
1630 <tr class="layout">
1631 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1632 <td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1633 </tr>
1634</table>
1635
Dan Gohman87ec5ad2009-11-09 19:01:53 +0000[diff] [blame]1636<p>There is no restriction on indexing beyond the end of the array implied by
1637 a static type (though there are restrictions on indexing beyond the bounds
1638 of an allocated object in some cases). This means that single-dimension
1639 'variable sized array' addressing can be implemented in LLVM with a zero
1640 length array type. An implementation of 'pascal style arrays' in LLVM could
1641 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1642
1643</div>
1644
1645<!-- _______________________________________________________________________ -->
1646<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1647
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1648<div class="doc_text">
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1649
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1650<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1651<p>The function type can be thought of as a function signature. It consists of
1652 a return type and a list of formal parameter types. The return type of a
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1653 function type is a scalar type, a void type, a struct type, or a union
1654 type. If the return type is a struct type then all struct elements must be
1655 of first class types, and the struct must have at least one element.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1656
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1657<h5>Syntax:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1658<pre>
Nick Lewycky3b3b54d2009-09-27 07:55:32 +0000[diff] [blame]1659 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1660</pre>
1661
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1662<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1663 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1664 which indicates that the function takes a variable number of arguments.
1665 Variable argument functions can access their arguments with
1666 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner553fb1e2010-03-02 06:36:51 +0000[diff] [blame]1667 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewyckyeb021882009-09-27 23:27:42 +0000[diff] [blame]1668 <a href="#t_label">label</a>.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1669
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1670<h5>Examples:</h5>
1671<table class="layout">
1672 <tr class="layout">
1673 <td class="left"><tt>i32 (i32)</tt></td>
1674 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
1675 </td>
1676 </tr><tr class="layout">
Chris Lattner553fb1e2010-03-02 06:36:51 +0000[diff] [blame]1677 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1678 </tt></td>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1679 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner553fb1e2010-03-02 06:36:51 +0000[diff] [blame]1680 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
1681 returning <tt>float</tt>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1682 </td>
1683 </tr><tr class="layout">
1684 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1685 <td class="left">A vararg function that takes at least one
1686 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1687 which returns an integer. This is the signature for <tt>printf</tt> in
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1688 LLVM.
1689 </td>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1690 </tr><tr class="layout">
1691 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky3b3b54d2009-09-27 07:55:32 +0000[diff] [blame]1692 <td class="left">A function taking an <tt>i32</tt>, returning a
1693 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1694 </td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1695 </tr>
1696</table>
1697
1698</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1699
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1700<!-- _______________________________________________________________________ -->
1701<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1702
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1703<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1704
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1705<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1706<p>The structure type is used to represent a collection of data members together
1707 in memory. The packing of the field types is defined to match the ABI of the
1708 underlying processor. The elements of a structure may be any type that has a
1709 size.</p>
1710
Jeffrey Yasskine05d7732010-01-11 19:19:26 +0000[diff] [blame]1711<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
1712 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
1713 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1714 Structures in registers are accessed using the
1715 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
1716 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1717<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1718<pre>
1719 { &lt;type list&gt; }
1720</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1721
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1722<h5>Examples:</h5>
1723<table class="layout">
1724 <tr class="layout">
1725 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1726 <td class="left">A triple of three <tt>i32</tt> values</td>
1727 </tr><tr class="layout">
1728 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1729 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1730 second element is a <a href="#t_pointer">pointer</a> to a
1731 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1732 an <tt>i32</tt>.</td>
1733 </tr>
1734</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1735
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1736</div>
1737
1738<!-- _______________________________________________________________________ -->
1739<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1740</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1741
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1742<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1743
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1744<h5>Overview:</h5>
1745<p>The packed structure type is used to represent a collection of data members
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1746 together in memory. There is no padding between fields. Further, the
1747 alignment of a packed structure is 1 byte. The elements of a packed
1748 structure may be any type that has a size.</p>
1749
1750<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1751 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1752 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1753
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1754<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1755<pre>
1756 &lt; { &lt;type list&gt; } &gt;
1757</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1758
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1759<h5>Examples:</h5>
1760<table class="layout">
1761 <tr class="layout">
1762 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1763 <td class="left">A triple of three <tt>i32</tt> values</td>
1764 </tr><tr class="layout">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1765 <td class="left">
1766<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1767 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1768 second element is a <a href="#t_pointer">pointer</a> to a
1769 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1770 an <tt>i32</tt>.</td>
1771 </tr>
1772</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1773
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1774</div>
1775
1776<!-- _______________________________________________________________________ -->
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1777<div class="doc_subsubsection"> <a name="t_union">Union Type</a> </div>
1778
1779<div class="doc_text">
1780
1781<h5>Overview:</h5>
1782<p>A union type describes an object with size and alignment suitable for
1783 an object of any one of a given set of types (also known as an "untagged"
1784 union). It is similar in concept and usage to a
1785 <a href="#t_struct">struct</a>, except that all members of the union
1786 have an offset of zero. The elements of a union may be any type that has a
1787 size. Unions must have at least one member - empty unions are not allowed.
1788 </p>
1789
1790<p>The size of the union as a whole will be the size of its largest member,
1791 and the alignment requirements of the union as a whole will be the largest
1792 alignment requirement of any member.</p>
1793
Dan Gohmanef8400c2010-02-25 16:51:31 +0000[diff] [blame]1794<p>Union members are accessed using '<tt><a href="#i_load">load</a></tt> and
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1795 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1796 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1797 Since all members are at offset zero, the getelementptr instruction does
1798 not affect the address, only the type of the resulting pointer.</p>
1799
1800<h5>Syntax:</h5>
1801<pre>
1802 union { &lt;type list&gt; }
1803</pre>
1804
1805<h5>Examples:</h5>
1806<table class="layout">
1807 <tr class="layout">
1808 <td class="left"><tt>union { i32, i32*, float }</tt></td>
1809 <td class="left">A union of three types: an <tt>i32</tt>, a pointer to
1810 an <tt>i32</tt>, and a <tt>float</tt>.</td>
1811 </tr><tr class="layout">
1812 <td class="left">
1813 <tt>union {&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1814 <td class="left">A union, where the first element is a <tt>float</tt> and the
1815 second element is a <a href="#t_pointer">pointer</a> to a
1816 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1817 an <tt>i32</tt>.</td>
1818 </tr>
1819</table>
1820
1821</div>
1822
1823<!-- _______________________________________________________________________ -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1824<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1825
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1826<div class="doc_text">
1827
1828<h5>Overview:</h5>
Dan Gohmanb2f72c82010-02-25 16:50:07 +0000[diff] [blame]1829<p>The pointer type is used to specify memory locations.
1830 Pointers are commonly used to reference objects in memory.</p>
1831
1832<p>Pointer types may have an optional address space attribute defining the
1833 numbered address space where the pointed-to object resides. The default
1834 address space is number zero. The semantics of non-zero address
1835 spaces are target-specific.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1836
1837<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1838 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1839
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1840<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1841<pre>
1842 &lt;type&gt; *
1843</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1844
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1845<h5>Examples:</h5>
1846<table class="layout">
1847 <tr class="layout">
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]1848 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1849 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1850 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1851 </tr>
1852 <tr class="layout">
1853 <td class="left"><tt>i32 (i32 *) *</tt></td>
1854 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1855 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1856 <tt>i32</tt>.</td>
1857 </tr>
1858 <tr class="layout">
1859 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1860 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1861 that resides in address space #5.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1862 </tr>
1863</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1864
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1865</div>
1866
1867<!-- _______________________________________________________________________ -->
1868<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1869
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1870<div class="doc_text">
1871
1872<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1873<p>A vector type is a simple derived type that represents a vector of elements.
1874 Vector types are used when multiple primitive data are operated in parallel
1875 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sands87598b02009-11-27 13:38:03 +0000[diff] [blame]1876 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1877 <a href="#t_firstclass">first class</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1878
1879<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1880<pre>
1881 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1882</pre>
1883
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1884<p>The number of elements is a constant integer value; elementtype may be any
1885 integer or floating point type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1886
1887<h5>Examples:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1888<table class="layout">
1889 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1890 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1891 <td class="left">Vector of 4 32-bit integer values.</td>
1892 </tr>
1893 <tr class="layout">
1894 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1895 <td class="left">Vector of 8 32-bit floating-point values.</td>
1896 </tr>
1897 <tr class="layout">
1898 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1899 <td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1900 </tr>
1901</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1902
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1903</div>
1904
1905<!-- _______________________________________________________________________ -->
1906<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1907<div class="doc_text">
1908
1909<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1910<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1911 corresponds (for example) to the C notion of a forward declared structure
1912 type. In LLVM, opaque types can eventually be resolved to any type (not just
1913 a structure type).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1914
1915<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1916<pre>
1917 opaque
1918</pre>
1919
1920<h5>Examples:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1921<table class="layout">
1922 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1923 <td class="left"><tt>opaque</tt></td>
1924 <td class="left">An opaque type.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1925 </tr>
1926</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1927
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1928</div>
1929
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1930<!-- ======================================================================= -->
1931<div class="doc_subsection">
1932 <a name="t_uprefs">Type Up-references</a>
1933</div>
1934
1935<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1936
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1937<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1938<p>An "up reference" allows you to refer to a lexically enclosing type without
1939 requiring it to have a name. For instance, a structure declaration may
1940 contain a pointer to any of the types it is lexically a member of. Example
1941 of up references (with their equivalent as named type declarations)
1942 include:</p>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1943
1944<pre>
Chris Lattner5ad632d2009-02-09 10:00:56 +0000[diff] [blame]1945 { \2 * } %x = type { %x* }
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1946 { \2 }* %y = type { %y }*
1947 \1* %z = type %z*
1948</pre>
1949
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1950<p>An up reference is needed by the asmprinter for printing out cyclic types
1951 when there is no declared name for a type in the cycle. Because the
1952 asmprinter does not want to print out an infinite type string, it needs a
1953 syntax to handle recursive types that have no names (all names are optional
1954 in llvm IR).</p>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1955
1956<h5>Syntax:</h5>
1957<pre>
1958 \&lt;level&gt;
1959</pre>
1960
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1961<p>The level is the count of the lexical type that is being referred to.</p>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1962
1963<h5>Examples:</h5>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1964<table class="layout">
1965 <tr class="layout">
1966 <td class="left"><tt>\1*</tt></td>
1967 <td class="left">Self-referential pointer.</td>
1968 </tr>
1969 <tr class="layout">
1970 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1971 <td class="left">Recursive structure where the upref refers to the out-most
1972 structure.</td>
1973 </tr>
1974</table>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1975
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1976</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1977
1978<!-- *********************************************************************** -->
1979<div class="doc_section"> <a name="constants">Constants</a> </div>
1980<!-- *********************************************************************** -->
1981
1982<div class="doc_text">
1983
1984<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1985 them all and their syntax.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1986
1987</div>
1988
1989<!-- ======================================================================= -->
1990<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
1991
1992<div class="doc_text">
1993
1994<dl>
1995 <dt><b>Boolean constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1996 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1997 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1998
1999 <dt><b>Integer constants</b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2000 <dd>Standard integers (such as '4') are constants of
2001 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2002 with integer types.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2003
2004 <dt><b>Floating point constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2005 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2006 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2007 notation (see below). The assembler requires the exact decimal value of a
2008 floating-point constant. For example, the assembler accepts 1.25 but
2009 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2010 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2011
2012 <dt><b>Null pointer constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2013 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2014 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2015</dl>
2016
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2017<p>The one non-intuitive notation for constants is the hexadecimal form of
2018 floating point constants. For example, the form '<tt>double
2019 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2020 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2021 constants are required (and the only time that they are generated by the
2022 disassembler) is when a floating point constant must be emitted but it cannot
2023 be represented as a decimal floating point number in a reasonable number of
2024 digits. For example, NaN's, infinities, and other special values are
2025 represented in their IEEE hexadecimal format so that assembly and disassembly
2026 do not cause any bits to change in the constants.</p>
2027
Dale Johannesenf82a52f2009-02-11 22:14:51 +0000[diff] [blame]2028<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2029 represented using the 16-digit form shown above (which matches the IEEE754
2030 representation for double); float values must, however, be exactly
2031 representable as IEE754 single precision. Hexadecimal format is always used
2032 for long double, and there are three forms of long double. The 80-bit format
2033 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2034 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2035 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2036 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2037 currently supported target uses this format. Long doubles will only work if
2038 they match the long double format on your target. All hexadecimal formats
2039 are big-endian (sign bit at the left).</p>
2040
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2041</div>
2042
2043<!-- ======================================================================= -->
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]2044<div class="doc_subsection">
Bill Wendling1a2630a2009-07-20 02:32:41 +0000[diff] [blame]2045<a name="aggregateconstants"></a> <!-- old anchor -->
2046<a name="complexconstants">Complex Constants</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2047</div>
2048
2049<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2050
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]2051<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2052 constants and smaller complex constants.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2053
2054<dl>
2055 <dt><b>Structure constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2056 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2057 type definitions (a comma separated list of elements, surrounded by braces
2058 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2059 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2060 Structure constants must have <a href="#t_struct">structure type</a>, and
2061 the number and types of elements must match those specified by the
2062 type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2063
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]2064 <dt><b>Union constants</b></dt>
2065 <dd>Union constants are represented with notation similar to a structure with
2066 a single element - that is, a single typed element surrounded
2067 by braces (<tt>{}</tt>)). For example: "<tt>{ i32 4 }</tt>". The
2068 <a href="#t_union">union type</a> can be initialized with a single-element
2069 struct as long as the type of the struct element matches the type of
2070 one of the union members.</dd>
2071
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2072 <dt><b>Array constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2073 <dd>Array constants are represented with notation similar to array type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2074 definitions (a comma separated list of elements, surrounded by square
2075 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2076 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2077 the number and types of elements must match those specified by the
2078 type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2079
2080 <dt><b>Vector constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2081 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2082 definitions (a comma separated list of elements, surrounded by
2083 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2084 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2085 have <a href="#t_vector">vector type</a>, and the number and types of
2086 elements must match those specified by the type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2087
2088 <dt><b>Zero initialization</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2089 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]2090 value to zero of <em>any</em> type, including scalar and
2091 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2092 This is often used to avoid having to print large zero initializers
2093 (e.g. for large arrays) and is always exactly equivalent to using explicit
2094 zero initializers.</dd>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2095
2096 <dt><b>Metadata node</b></dt>
Nick Lewyckyf122c7e2009-05-30 16:08:30 +0000[diff] [blame]2097 <dd>A metadata node is a structure-like constant with
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2098 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2099 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2100 be interpreted as part of the instruction stream, metadata is a place to
2101 attach additional information such as debug info.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2102</dl>
2103
2104</div>
2105
2106<!-- ======================================================================= -->
2107<div class="doc_subsection">
2108 <a name="globalconstants">Global Variable and Function Addresses</a>
2109</div>
2110
2111<div class="doc_text">
2112
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2113<p>The addresses of <a href="#globalvars">global variables</a>
2114 and <a href="#functionstructure">functions</a> are always implicitly valid
2115 (link-time) constants. These constants are explicitly referenced when
2116 the <a href="#identifiers">identifier for the global</a> is used and always
2117 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2118 legal LLVM file:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2119
2120<div class="doc_code">
2121<pre>
2122@X = global i32 17
2123@Y = global i32 42
2124@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
2125</pre>
2126</div>
2127
2128</div>
2129
2130<!-- ======================================================================= -->
2131<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
2132<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2133
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2134<p>The string '<tt>undef</tt>' can be used anywhere a constant is expected, and
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2135 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2136 Undefined values may be of any type (other than label or void) and be used
2137 anywhere a constant is permitted.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2138
Chris Lattner9d1e4fa2009-09-11 01:49:31 +0000[diff] [blame]2139<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2140 program is well defined no matter what value is used. This gives the
2141 compiler more freedom to optimize. Here are some examples of (potentially
2142 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2143
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2144
2145<div class="doc_code">
2146<pre>
2147 %A = add %X, undef
2148 %B = sub %X, undef
2149 %C = xor %X, undef
2150Safe:
2151 %A = undef
2152 %B = undef
2153 %C = undef
2154</pre>
2155</div>
2156
2157<p>This is safe because all of the output bits are affected by the undef bits.
2158Any output bit can have a zero or one depending on the input bits.</p>
2159
2160<div class="doc_code">
2161<pre>
2162 %A = or %X, undef
2163 %B = and %X, undef
2164Safe:
2165 %A = -1
2166 %B = 0
2167Unsafe:
2168 %A = undef
2169 %B = undef
2170</pre>
2171</div>
2172
2173<p>These logical operations have bits that are not always affected by the input.
2174For example, if "%X" has a zero bit, then the output of the 'and' operation will
2175always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattner9d1e4fa2009-09-11 01:49:31 +0000[diff] [blame]2176such, it is unsafe to optimize or assume that the result of the and is undef.
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2177However, it is safe to assume that all bits of the undef could be 0, and
2178optimize the and to 0. Likewise, it is safe to assume that all the bits of
2179the undef operand to the or could be set, allowing the or to be folded to
Chris Lattner9d1e4fa2009-09-11 01:49:31 +0000[diff] [blame]2180-1.</p>
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2181
2182<div class="doc_code">
2183<pre>
2184 %A = select undef, %X, %Y
2185 %B = select undef, 42, %Y
2186 %C = select %X, %Y, undef
2187Safe:
2188 %A = %X (or %Y)
2189 %B = 42 (or %Y)
2190 %C = %Y
2191Unsafe:
2192 %A = undef
2193 %B = undef
2194 %C = undef
2195</pre>
2196</div>
2197
2198<p>This set of examples show that undefined select (and conditional branch)
2199conditions can go "either way" but they have to come from one of the two
2200operands. In the %A example, if %X and %Y were both known to have a clear low
2201bit, then %A would have to have a cleared low bit. However, in the %C example,
2202the optimizer is allowed to assume that the undef operand could be the same as
2203%Y, allowing the whole select to be eliminated.</p>
2204
2205
2206<div class="doc_code">
2207<pre>
2208 %A = xor undef, undef
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2209
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2210 %B = undef
2211 %C = xor %B, %B
2212
2213 %D = undef
2214 %E = icmp lt %D, 4
2215 %F = icmp gte %D, 4
2216
2217Safe:
2218 %A = undef
2219 %B = undef
2220 %C = undef
2221 %D = undef
2222 %E = undef
2223 %F = undef
2224</pre>
2225</div>
2226
2227<p>This example points out that two undef operands are not necessarily the same.
2228This can be surprising to people (and also matches C semantics) where they
2229assume that "X^X" is always zero, even if X is undef. This isn't true for a
2230number of reasons, but the short answer is that an undef "variable" can
2231arbitrarily change its value over its "live range". This is true because the
2232"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2233logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2234so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattnerc802e482009-09-08 15:13:16 +0000[diff] [blame]2235to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2236would not hold.</p>
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2237
2238<div class="doc_code">
2239<pre>
2240 %A = fdiv undef, %X
2241 %B = fdiv %X, undef
2242Safe:
2243 %A = undef
2244b: unreachable
2245</pre>
2246</div>
2247
2248<p>These examples show the crucial difference between an <em>undefined
2249value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2250allowed to have an arbitrary bit-pattern. This means that the %A operation
2251can be constant folded to undef because the undef could be an SNaN, and fdiv is
2252not (currently) defined on SNaN's. However, in the second example, we can make
2253a more aggressive assumption: because the undef is allowed to be an arbitrary
2254value, we are allowed to assume that it could be zero. Since a divide by zero
Chris Lattner83d45d72009-09-08 19:45:34 +0000[diff] [blame]2255has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2256does not execute at all. This allows us to delete the divide and all code after
2257it: since the undefined operation "can't happen", the optimizer can assume that
2258it occurs in dead code.
2259</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2260
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2261<div class="doc_code">
2262<pre>
2263a: store undef -> %X
2264b: store %X -> undef
2265Safe:
2266a: &lt;deleted&gt;
2267b: unreachable
2268</pre>
2269</div>
2270
2271<p>These examples reiterate the fdiv example: a store "of" an undefined value
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2272can be assumed to not have any effect: we can assume that the value is
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2273overwritten with bits that happen to match what was already there. However, a
2274store "to" an undefined location could clobber arbitrary memory, therefore, it
2275has undefined behavior.</p>
2276
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2277</div>
2278
2279<!-- ======================================================================= -->
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]2280<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2281 Blocks</a></div>
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2282<div class="doc_text">
2283
Chris Lattner620cead2009-11-01 01:27:45 +0000[diff] [blame]2284<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2285
2286<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner24f2e852009-10-27 21:49:40 +0000[diff] [blame]2287 basic block in the specified function, and always has an i8* type. Taking
Chris Lattner620cead2009-11-01 01:27:45 +0000[diff] [blame]2288 the address of the entry block is illegal.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2289
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2290<p>This value only has defined behavior when used as an operand to the
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2291 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2292 against null. Pointer equality tests between labels addresses is undefined
2293 behavior - though, again, comparison against null is ok, and no label is
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]2294 equal to the null pointer. This may also be passed around as an opaque
2295 pointer sized value as long as the bits are not inspected. This allows
Chris Lattner0bae7b32009-10-27 21:44:20 +0000[diff] [blame]2296 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2297 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2298
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]2299<p>Finally, some targets may provide defined semantics when
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2300 using the value as the operand to an inline assembly, but that is target
2301 specific.
2302 </p>
2303
2304</div>
2305
2306
2307<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2308<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2309</div>
2310
2311<div class="doc_text">
2312
2313<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2314 to be used as constants. Constant expressions may be of
2315 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2316 operation that does not have side effects (e.g. load and call are not
2317 supported). The following is the syntax for constant expressions:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2318
2319<dl>
2320 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2321 <dd>Truncate a constant to another type. The bit size of CST must be larger
2322 than the bit size of TYPE. Both types must be integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2323
2324 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2325 <dd>Zero extend a constant to another type. The bit size of CST must be
2326 smaller or equal to the bit size of TYPE. Both types must be
2327 integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2328
2329 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2330 <dd>Sign extend a constant to another type. The bit size of CST must be
2331 smaller or equal to the bit size of TYPE. Both types must be
2332 integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2333
2334 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2335 <dd>Truncate a floating point constant to another floating point type. The
2336 size of CST must be larger than the size of TYPE. Both types must be
2337 floating point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2338
2339 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2340 <dd>Floating point extend a constant to another type. The size of CST must be
2341 smaller or equal to the size of TYPE. Both types must be floating
2342 point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2343
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]2344 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2345 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2346 constant. TYPE must be a scalar or vector integer type. CST must be of
2347 scalar or vector floating point type. Both CST and TYPE must be scalars,
2348 or vectors of the same number of elements. If the value won't fit in the
2349 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2350
2351 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
2352 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2353 constant. TYPE must be a scalar or vector integer type. CST must be of
2354 scalar or vector floating point type. Both CST and TYPE must be scalars,
2355 or vectors of the same number of elements. If the value won't fit in the
2356 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2357
2358 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
2359 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2360 constant. TYPE must be a scalar or vector floating point type. CST must be
2361 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2362 vectors of the same number of elements. If the value won't fit in the
2363 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2364
2365 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
2366 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2367 constant. TYPE must be a scalar or vector floating point type. CST must be
2368 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2369 vectors of the same number of elements. If the value won't fit in the
2370 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2371
2372 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2373 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2374 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2375 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2376 make it fit in <tt>TYPE</tt>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2377
2378 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2379 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2380 type. CST must be of integer type. The CST value is zero extended,
2381 truncated, or unchanged to make it fit in a pointer size. This one is
2382 <i>really</i> dangerous!</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2383
2384 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner557bc5d2009-02-28 18:27:03 +0000[diff] [blame]2385 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2386 are the same as those for the <a href="#i_bitcast">bitcast
2387 instruction</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2388
2389 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]2390 <dt><b><tt>getelementptr inbounds ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2391 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2392 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2393 instruction, the index list may have zero or more indexes, which are
2394 required to make sense for the type of "CSTPTR".</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2395
2396 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2397 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2398
2399 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2400 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2401
2402 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2403 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
2404
2405 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2406 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2407 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2408
2409 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2410 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2411 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2412
2413 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2414 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2415 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2416
2417 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2418 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2419 be any of the <a href="#binaryops">binary</a>
2420 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2421 on operands are the same as those for the corresponding instruction
2422 (e.g. no bitwise operations on floating point values are allowed).</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2423</dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2424
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2425</div>
2426
2427<!-- *********************************************************************** -->
2428<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2429<!-- *********************************************************************** -->
2430
2431<!-- ======================================================================= -->
2432<div class="doc_subsection">
2433<a name="inlineasm">Inline Assembler Expressions</a>
2434</div>
2435
2436<div class="doc_text">
2437
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2438<p>LLVM supports inline assembler expressions (as opposed
2439 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2440 a special value. This value represents the inline assembler as a string
2441 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2442 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2443 expression has side effects, and a flag indicating whether the function
2444 containing the asm needs to align its stack conservatively. An example
2445 inline assembler expression is:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2446
2447<div class="doc_code">
2448<pre>
2449i32 (i32) asm "bswap $0", "=r,r"
2450</pre>
2451</div>
2452
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2453<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2454 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2455 have:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2456
2457<div class="doc_code">
2458<pre>
2459%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
2460</pre>
2461</div>
2462
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2463<p>Inline asms with side effects not visible in the constraint list must be
2464 marked as having side effects. This is done through the use of the
2465 '<tt>sideeffect</tt>' keyword, like so:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2466
2467<div class="doc_code">
2468<pre>
2469call void asm sideeffect "eieio", ""()
2470</pre>
2471</div>
2472
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2473<p>In some cases inline asms will contain code that will not work unless the
2474 stack is aligned in some way, such as calls or SSE instructions on x86,
2475 yet will not contain code that does that alignment within the asm.
2476 The compiler should make conservative assumptions about what the asm might
2477 contain and should generate its usual stack alignment code in the prologue
2478 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2479
2480<div class="doc_code">
2481<pre>
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2482call void asm alignstack "eieio", ""()
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2483</pre>
2484</div>
2485
2486<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2487 first.</p>
2488
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2489<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2490 documented here. Constraints on what can be done (e.g. duplication, moving,
2491 etc need to be documented). This is probably best done by reference to
2492 another document that covers inline asm from a holistic perspective.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2493
2494</div>
2495
Chris Lattnerd0d96292010-01-15 21:50:19 +0000[diff] [blame]2496<!-- ======================================================================= -->
2497<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
2498 Strings</a>
2499</div>
2500
2501<div class="doc_text">
2502
2503<p>LLVM IR allows metadata to be attached to instructions in the program that
2504 can convey extra information about the code to the optimizers and code
2505 generator. One example application of metadata is source-level debug
2506 information. There are two metadata primitives: strings and nodes. All
2507 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2508 preceding exclamation point ('<tt>!</tt>').</p>
2509
2510<p>A metadata string is a string surrounded by double quotes. It can contain
2511 any character by escaping non-printable characters with "\xx" where "xx" is
2512 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2513
2514<p>Metadata nodes are represented with notation similar to structure constants
2515 (a comma separated list of elements, surrounded by braces and preceded by an
2516 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2517 10}</tt>". Metadata nodes can have any values as their operand.</p>
2518
2519<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2520 metadata nodes, which can be looked up in the module symbol table. For
2521 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2522
Devang Patelb1586922010-03-04 23:44:48 +0000[diff] [blame^]2523<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
2524 function is using two metadata arguments.
2525
2526 <div class="doc_code">
2527 <pre>
2528 call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2529 </pre>
2530 </div></p>
2531
2532<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
2533 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.
2534
2535 <div class="doc_code">
2536 <pre>
2537 %indvar.next = add i64 %indvar, 1, !dbg !21
2538 </pre>
2539 </div></p>
Chris Lattnerd0d96292010-01-15 21:50:19 +0000[diff] [blame]2540</div>
2541
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2542
2543<!-- *********************************************************************** -->
2544<div class="doc_section">
2545 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2546</div>
2547<!-- *********************************************************************** -->
2548
2549<p>LLVM has a number of "magic" global variables that contain data that affect
2550code generation or other IR semantics. These are documented here. All globals
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2551of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2552section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2553by LLVM.</p>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2554
2555<!-- ======================================================================= -->
2556<div class="doc_subsection">
2557<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2558</div>
2559
2560<div class="doc_text">
2561
2562<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2563href="#linkage_appending">appending linkage</a>. This array contains a list of
2564pointers to global variables and functions which may optionally have a pointer
2565cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2566
2567<pre>
2568 @X = global i8 4
2569 @Y = global i32 123
2570
2571 @llvm.used = appending global [2 x i8*] [
2572 i8* @X,
2573 i8* bitcast (i32* @Y to i8*)
2574 ], section "llvm.metadata"
2575</pre>
2576
2577<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2578compiler, assembler, and linker are required to treat the symbol as if there is
2579a reference to the global that it cannot see. For example, if a variable has
2580internal linkage and no references other than that from the <tt>@llvm.used</tt>
2581list, it cannot be deleted. This is commonly used to represent references from
2582inline asms and other things the compiler cannot "see", and corresponds to
2583"attribute((used))" in GNU C.</p>
2584
2585<p>On some targets, the code generator must emit a directive to the assembler or
2586object file to prevent the assembler and linker from molesting the symbol.</p>
2587
2588</div>
2589
2590<!-- ======================================================================= -->
2591<div class="doc_subsection">
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2592<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2593</div>
2594
2595<div class="doc_text">
2596
2597<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2598<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2599touching the symbol. On targets that support it, this allows an intelligent
2600linker to optimize references to the symbol without being impeded as it would be
2601by <tt>@llvm.used</tt>.</p>
2602
2603<p>This is a rare construct that should only be used in rare circumstances, and
2604should not be exposed to source languages.</p>
2605
2606</div>
2607
2608<!-- ======================================================================= -->
2609<div class="doc_subsection">
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2610<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2611</div>
2612
2613<div class="doc_text">
2614
2615<p>TODO: Describe this.</p>
2616
2617</div>
2618
2619<!-- ======================================================================= -->
2620<div class="doc_subsection">
2621<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2622</div>
2623
2624<div class="doc_text">
2625
2626<p>TODO: Describe this.</p>
2627
2628</div>
2629
2630
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2631<!-- *********************************************************************** -->
2632<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2633<!-- *********************************************************************** -->
2634
2635<div class="doc_text">
2636
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2637<p>The LLVM instruction set consists of several different classifications of
2638 instructions: <a href="#terminators">terminator
2639 instructions</a>, <a href="#binaryops">binary instructions</a>,
2640 <a href="#bitwiseops">bitwise binary instructions</a>,
2641 <a href="#memoryops">memory instructions</a>, and
2642 <a href="#otherops">other instructions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2643
2644</div>
2645
2646<!-- ======================================================================= -->
2647<div class="doc_subsection"> <a name="terminators">Terminator
2648Instructions</a> </div>
2649
2650<div class="doc_text">
2651
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2652<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2653 in a program ends with a "Terminator" instruction, which indicates which
2654 block should be executed after the current block is finished. These
2655 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2656 control flow, not values (the one exception being the
2657 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2658
2659<p>There are six different terminator instructions: the
2660 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2661 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2662 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendlingb4ae2292009-11-02 00:25:26 +0000[diff] [blame]2663 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2664 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2665 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2666 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2667
2668</div>
2669
2670<!-- _______________________________________________________________________ -->
2671<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2672Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2673
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2674<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2675
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2676<h5>Syntax:</h5>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2677<pre>
2678 ret &lt;type&gt; &lt;value&gt; <i>; Return a value from a non-void function</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2679 ret void <i>; Return from void function</i>
2680</pre>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2681
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2682<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2683<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2684 a value) from a function back to the caller.</p>
2685
2686<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2687 value and then causes control flow, and one that just causes control flow to
2688 occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2689
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2690<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2691<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2692 return value. The type of the return value must be a
2693 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2694
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2695<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2696 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2697 value or a return value with a type that does not match its type, or if it
2698 has a void return type and contains a '<tt>ret</tt>' instruction with a
2699 return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2700
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2701<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2702<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2703 the calling function's context. If the caller is a
2704 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2705 instruction after the call. If the caller was an
2706 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2707 the beginning of the "normal" destination block. If the instruction returns
2708 a value, that value shall set the call or invoke instruction's return
2709 value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2710
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2711<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2712<pre>
2713 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2714 ret void <i>; Return from a void function</i>
Bill Wendlingd163e2d2009-02-28 22:12:54 +0000[diff] [blame]2715 ret { i32, i8 } { i32 4, i8 2 } <i>; Return a struct of values 4 and 2</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2716</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2717
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2718</div>
2719<!-- _______________________________________________________________________ -->
2720<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2721
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2722<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2723
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2724<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2725<pre>
2726 br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2727</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2728
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2729<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2730<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2731 different basic block in the current function. There are two forms of this
2732 instruction, corresponding to a conditional branch and an unconditional
2733 branch.</p>
2734
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2735<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2736<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2737 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2738 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2739 target.</p>
2740
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2741<h5>Semantics:</h5>
2742<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2743 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2744 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2745 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2746
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2747<h5>Example:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]2748<pre>
2749Test:
2750 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2751 br i1 %cond, label %IfEqual, label %IfUnequal
2752IfEqual:
2753 <a href="#i_ret">ret</a> i32 1
2754IfUnequal:
2755 <a href="#i_ret">ret</a> i32 0
2756</pre>
2757
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2758</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2759
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2760<!-- _______________________________________________________________________ -->
2761<div class="doc_subsubsection">
2762 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2763</div>
2764
2765<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2766
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2767<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2768<pre>
2769 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2770</pre>
2771
2772<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2773<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2774 several different places. It is a generalization of the '<tt>br</tt>'
2775 instruction, allowing a branch to occur to one of many possible
2776 destinations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2777
2778<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2779<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2780 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2781 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2782 The table is not allowed to contain duplicate constant entries.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2783
2784<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2785<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2786 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2787 is searched for the given value. If the value is found, control flow is
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2788 transferred to the corresponding destination; otherwise, control flow is
2789 transferred to the default destination.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2790
2791<h5>Implementation:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2792<p>Depending on properties of the target machine and the particular
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2793 <tt>switch</tt> instruction, this instruction may be code generated in
2794 different ways. For example, it could be generated as a series of chained
2795 conditional branches or with a lookup table.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2796
2797<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2798<pre>
2799 <i>; Emulate a conditional br instruction</i>
2800 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2801 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2802
2803 <i>; Emulate an unconditional br instruction</i>
2804 switch i32 0, label %dest [ ]
2805
2806 <i>; Implement a jump table:</i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2807 switch i32 %val, label %otherwise [ i32 0, label %onzero
2808 i32 1, label %onone
2809 i32 2, label %ontwo ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2810</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2811
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2812</div>
2813
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2814
2815<!-- _______________________________________________________________________ -->
2816<div class="doc_subsubsection">
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2817 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2818</div>
2819
2820<div class="doc_text">
2821
2822<h5>Syntax:</h5>
2823<pre>
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2824 indirectbr &lt;somety&gt;* &lt;address&gt;, [ label &lt;dest1&gt;, label &lt;dest2&gt;, ... ]
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2825</pre>
2826
2827<h5>Overview:</h5>
2828
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2829<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2830 within the current function, whose address is specified by
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2831 "<tt>address</tt>". Address must be derived from a <a
2832 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2833
2834<h5>Arguments:</h5>
2835
2836<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
2837 rest of the arguments indicate the full set of possible destinations that the
2838 address may point to. Blocks are allowed to occur multiple times in the
2839 destination list, though this isn't particularly useful.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2840
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2841<p>This destination list is required so that dataflow analysis has an accurate
2842 understanding of the CFG.</p>
2843
2844<h5>Semantics:</h5>
2845
2846<p>Control transfers to the block specified in the address argument. All
2847 possible destination blocks must be listed in the label list, otherwise this
2848 instruction has undefined behavior. This implies that jumps to labels
2849 defined in other functions have undefined behavior as well.</p>
2850
2851<h5>Implementation:</h5>
2852
2853<p>This is typically implemented with a jump through a register.</p>
2854
2855<h5>Example:</h5>
2856<pre>
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2857 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2858</pre>
2859
2860</div>
2861
2862
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2863<!-- _______________________________________________________________________ -->
2864<div class="doc_subsubsection">
2865 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2866</div>
2867
2868<div class="doc_text">
2869
2870<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2871<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2872 &lt;result&gt; = invoke [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>] &lt;ptr to function ty&gt; &lt;function ptr val&gt;(&lt;function args&gt;) [<a href="#fnattrs">fn attrs</a>]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2873 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
2874</pre>
2875
2876<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2877<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2878 function, with the possibility of control flow transfer to either the
2879 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
2880 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
2881 control flow will return to the "normal" label. If the callee (or any
2882 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
2883 instruction, control is interrupted and continued at the dynamically nearest
2884 "exception" label.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2885
2886<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2887<p>This instruction requires several arguments:</p>
2888
2889<ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2890 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
2891 convention</a> the call should use. If none is specified, the call
2892 defaults to using C calling conventions.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2893
2894 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2895 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
2896 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2897
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2898 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2899 function value being invoked. In most cases, this is a direct function
2900 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
2901 off an arbitrary pointer to function value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2902
2903 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2904 function to be invoked. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2905
2906 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner553fb1e2010-03-02 06:36:51 +0000[diff] [blame]2907 signature argument types and parameter attributes. All arguments must be
2908 of <a href="#t_firstclass">first class</a> type. If the function
2909 signature indicates the function accepts a variable number of arguments,
2910 the extra arguments can be specified.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2911
2912 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2913 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2914
2915 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2916 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2917
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2918 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2919 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2920 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2921</ol>
2922
2923<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2924<p>This instruction is designed to operate as a standard
2925 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
2926 primary difference is that it establishes an association with a label, which
2927 is used by the runtime library to unwind the stack.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2928
2929<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2930 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2931 exception. Additionally, this is important for implementation of
2932 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2933
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2934<p>For the purposes of the SSA form, the definition of the value returned by the
2935 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
2936 block to the "normal" label. If the callee unwinds then no return value is
2937 available.</p>
Dan Gohman140ba5d2009-05-22 21:47:08 +0000[diff] [blame]2938
Chris Lattner4a91ef42010-01-15 18:08:37 +0000[diff] [blame]2939<p>Note that the code generator does not yet completely support unwind, and
2940that the invoke/unwind semantics are likely to change in future versions.</p>
2941
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2942<h5>Example:</h5>
2943<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2944 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2945 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2946 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2947 unwind label %TestCleanup <i>; {i32}:retval set</i>
2948</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2949
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2950</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2951
2952<!-- _______________________________________________________________________ -->
2953
2954<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2955Instruction</a> </div>
2956
2957<div class="doc_text">
2958
2959<h5>Syntax:</h5>
2960<pre>
2961 unwind
2962</pre>
2963
2964<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2965<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2966 at the first callee in the dynamic call stack which used
2967 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
2968 This is primarily used to implement exception handling.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2969
2970<h5>Semantics:</h5>
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]2971<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2972 immediately halt. The dynamic call stack is then searched for the
2973 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
2974 Once found, execution continues at the "exceptional" destination block
2975 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
2976 instruction in the dynamic call chain, undefined behavior results.</p>
2977
Chris Lattner4a91ef42010-01-15 18:08:37 +0000[diff] [blame]2978<p>Note that the code generator does not yet completely support unwind, and
2979that the invoke/unwind semantics are likely to change in future versions.</p>
2980
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2981</div>
2982
2983<!-- _______________________________________________________________________ -->
2984
2985<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2986Instruction</a> </div>
2987
2988<div class="doc_text">
2989
2990<h5>Syntax:</h5>
2991<pre>
2992 unreachable
2993</pre>
2994
2995<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2996<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2997 instruction is used to inform the optimizer that a particular portion of the
2998 code is not reachable. This can be used to indicate that the code after a
2999 no-return function cannot be reached, and other facts.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3000
3001<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3002<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3003
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3004</div>
3005
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3006<!-- ======================================================================= -->
3007<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3008
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3009<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3010
3011<p>Binary operators are used to do most of the computation in a program. They
3012 require two operands of the same type, execute an operation on them, and
3013 produce a single value. The operands might represent multiple data, as is
3014 the case with the <a href="#t_vector">vector</a> data type. The result value
3015 has the same type as its operands.</p>
3016
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3017<p>There are several different binary operators:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3018
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3019</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3020
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3021<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3022<div class="doc_subsubsection">
3023 <a name="i_add">'<tt>add</tt>' Instruction</a>
3024</div>
3025
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3026<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3027
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3028<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3029<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3030 &lt;result&gt; = add &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanb3b03482009-09-02 17:31:42 +0000[diff] [blame]3031 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3032 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3033 &lt;result&gt; = add nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3034</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3035
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3036<h5>Overview:</h5>
3037<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3038
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3039<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3040<p>The two arguments to the '<tt>add</tt>' instruction must
3041 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3042 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3043
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3044<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3045<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3046
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3047<p>If the sum has unsigned overflow, the result returned is the mathematical
3048 result modulo 2<sup>n</sup>, where n is the bit width of the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3049
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3050<p>Because LLVM integers use a two's complement representation, this instruction
3051 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3052
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3053<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3054 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3055 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
3056 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3057
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3058<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3059<pre>
3060 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3061</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3062
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3063</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3064
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3065<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3066<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3067 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
3068</div>
3069
3070<div class="doc_text">
3071
3072<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3073<pre>
3074 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3075</pre>
3076
3077<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3078<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3079
3080<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3081<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3082 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3083 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3084
3085<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3086<p>The value produced is the floating point sum of the two operands.</p>
3087
3088<h5>Example:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3089<pre>
3090 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3091</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3092
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3093</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3094
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3095<!-- _______________________________________________________________________ -->
3096<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3097 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3098</div>
3099
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3100<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3101
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3102<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3103<pre>
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3104 &lt;result&gt; = sub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanb3b03482009-09-02 17:31:42 +0000[diff] [blame]3105 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3106 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3107 &lt;result&gt; = sub nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3108</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3109
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3110<h5>Overview:</h5>
3111<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3112 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3113
3114<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3115 '<tt>neg</tt>' instruction present in most other intermediate
3116 representations.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3117
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3118<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3119<p>The two arguments to the '<tt>sub</tt>' instruction must
3120 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3121 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3122
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3123<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3124<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3125
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3126<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3127 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3128 result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3129
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3130<p>Because LLVM integers use a two's complement representation, this instruction
3131 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3132
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3133<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3134 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3135 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
3136 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3137
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3138<h5>Example:</h5>
3139<pre>
3140 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
3141 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
3142</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3143
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3144</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3145
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3146<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3147<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3148 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3149</div>
3150
3151<div class="doc_text">
3152
3153<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3154<pre>
3155 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3156</pre>
3157
3158<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3159<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3160 operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3161
3162<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3163 '<tt>fneg</tt>' instruction present in most other intermediate
3164 representations.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3165
3166<h5>Arguments:</h5>
Bill Wendling1a2630a2009-07-20 02:32:41 +0000[diff] [blame]3167<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3168 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3169 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3170
3171<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3172<p>The value produced is the floating point difference of the two operands.</p>
3173
3174<h5>Example:</h5>
3175<pre>
3176 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3177 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3178</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3179
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3180</div>
3181
3182<!-- _______________________________________________________________________ -->
3183<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3184 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3185</div>
3186
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3187<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3188
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3189<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3190<pre>
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3191 &lt;result&gt; = mul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanb3b03482009-09-02 17:31:42 +0000[diff] [blame]3192 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3193 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3194 &lt;result&gt; = mul nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3195</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3196
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3197<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3198<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3199
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3200<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3201<p>The two arguments to the '<tt>mul</tt>' instruction must
3202 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3203 integer values. Both arguments must have identical types.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3204
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3205<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3206<p>The value produced is the integer product of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3207
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3208<p>If the result of the multiplication has unsigned overflow, the result
3209 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3210 width of the result.</p>
3211
3212<p>Because LLVM integers use a two's complement representation, and the result
3213 is the same width as the operands, this instruction returns the correct
3214 result for both signed and unsigned integers. If a full product
3215 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3216 be sign-extended or zero-extended as appropriate to the width of the full
3217 product.</p>
3218
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3219<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3220 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3221 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
3222 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3223
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3224<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3225<pre>
3226 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3227</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3228
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3229</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3230
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3231<!-- _______________________________________________________________________ -->
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3232<div class="doc_subsubsection">
3233 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3234</div>
3235
3236<div class="doc_text">
3237
3238<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3239<pre>
3240 &lt;result&gt; = fmul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3241</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3242
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3243<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3244<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3245
3246<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3247<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3248 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3249 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3250
3251<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3252<p>The value produced is the floating point product of the two operands.</p>
3253
3254<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3255<pre>
3256 &lt;result&gt; = fmul float 4.0, %var <i>; yields {float}:result = 4.0 * %var</i>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3257</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3258
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3259</div>
3260
3261<!-- _______________________________________________________________________ -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3262<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3263</a></div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3264
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3265<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3266
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3267<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3268<pre>
3269 &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3270</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3271
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3272<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3273<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3274
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3275<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3276<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3277 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3278 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3279
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3280<h5>Semantics:</h5>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3281<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3282
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3283<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3284 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3285
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3286<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3287
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3288<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3289<pre>
3290 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3291</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3292
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3293</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3294
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3295<!-- _______________________________________________________________________ -->
3296<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3297</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3298
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3299<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3300
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3301<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3302<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3303 &lt;result&gt; = sdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanb3b03482009-09-02 17:31:42 +0000[diff] [blame]3304 &lt;result&gt; = sdiv exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3305</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3306
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3307<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3308<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3309
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3310<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3311<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3312 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3313 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3314
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3315<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3316<p>The value produced is the signed integer quotient of the two operands rounded
3317 towards zero.</p>
3318
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3319<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3320 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3321
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3322<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3323 undefined behavior; this is a rare case, but can occur, for example, by doing
3324 a 32-bit division of -2147483648 by -1.</p>
3325
Dan Gohman67fa48e2009-07-22 00:04:19 +0000[diff] [blame]3326<p>If the <tt>exact</tt> keyword is present, the result value of the
3327 <tt>sdiv</tt> is undefined if the result would be rounded or if overflow
3328 would occur.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3329
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3330<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3331<pre>
3332 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3333</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3334
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3335</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3336
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3337<!-- _______________________________________________________________________ -->
3338<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
3339Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3340
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3341<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3342
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3343<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3344<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3345 &lt;result&gt; = fdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3346</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3347
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3348<h5>Overview:</h5>
3349<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3350
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3351<h5>Arguments:</h5>
3352<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3353 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3354 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3355
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3356<h5>Semantics:</h5>
3357<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3358
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3359<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3360<pre>
3361 &lt;result&gt; = fdiv float 4.0, %var <i>; yields {float}:result = 4.0 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3362</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3363
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3364</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3365
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3366<!-- _______________________________________________________________________ -->
3367<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3368</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3369
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3370<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3371
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3372<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3373<pre>
3374 &lt;result&gt; = urem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3375</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3376
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3377<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3378<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3379 division of its two arguments.</p>
3380
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3381<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3382<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3383 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3384 values. Both arguments must have identical types.</p>
3385
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3386<h5>Semantics:</h5>
3387<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3388 This instruction always performs an unsigned division to get the
3389 remainder.</p>
3390
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3391<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3392 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3393
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3394<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3395
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3396<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3397<pre>
3398 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3399</pre>
3400
3401</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3402
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3403<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3404<div class="doc_subsubsection">
3405 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3406</div>
3407
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3408<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3409
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3410<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3411<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3412 &lt;result&gt; = srem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3413</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3414
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3415<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3416<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3417 division of its two operands. This instruction can also take
3418 <a href="#t_vector">vector</a> versions of the values in which case the
3419 elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]3420
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3421<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3422<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3423 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3424 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3425
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3426<h5>Semantics:</h5>
3427<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3428 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3429 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3430 a value. For more information about the difference,
3431 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3432 Math Forum</a>. For a table of how this is implemented in various languages,
3433 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3434 Wikipedia: modulo operation</a>.</p>
3435
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3436<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3437 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3438
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3439<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3440 Overflow also leads to undefined behavior; this is a rare case, but can
3441 occur, for example, by taking the remainder of a 32-bit division of
3442 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3443 lets srem be implemented using instructions that return both the result of
3444 the division and the remainder.)</p>
3445
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3446<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3447<pre>
3448 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3449</pre>
3450
3451</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3452
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3453<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3454<div class="doc_subsubsection">
3455 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3456
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3457<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3458
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3459<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3460<pre>
3461 &lt;result&gt; = frem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3462</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3463
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3464<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3465<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3466 its two operands.</p>
3467
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3468<h5>Arguments:</h5>
3469<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3470 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3471 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3472
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3473<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3474<p>This instruction returns the <i>remainder</i> of a division. The remainder
3475 has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3476
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3477<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3478<pre>
3479 &lt;result&gt; = frem float 4.0, %var <i>; yields {float}:result = 4.0 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3480</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3481
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3482</div>
3483
3484<!-- ======================================================================= -->
3485<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3486Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3487
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3488<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3489
3490<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3491 program. They are generally very efficient instructions and can commonly be
3492 strength reduced from other instructions. They require two operands of the
3493 same type, execute an operation on them, and produce a single value. The
3494 resulting value is the same type as its operands.</p>
3495
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3496</div>
3497
3498<!-- _______________________________________________________________________ -->
3499<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3500Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3501
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3502<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3503
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3504<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3505<pre>
3506 &lt;result&gt; = shl &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3507</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3508
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3509<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3510<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3511 a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3512
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3513<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3514<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3515 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3516 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3517
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3518<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3519<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3520 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3521 is (statically or dynamically) negative or equal to or larger than the number
3522 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3523 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3524 shift amount in <tt>op2</tt>.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3525
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3526<h5>Example:</h5>
3527<pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3528 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3529 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3530 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3531 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3532 &lt;result&gt; = shl &lt;2 x i32&gt; &lt; i32 1, i32 1&gt;, &lt; i32 1, i32 2&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 2, i32 4&gt;</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3533</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3534
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3535</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3536
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3537<!-- _______________________________________________________________________ -->
3538<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3539Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3540
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3541<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3542
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3543<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3544<pre>
3545 &lt;result&gt; = lshr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3546</pre>
3547
3548<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3549<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3550 operand shifted to the right a specified number of bits with zero fill.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3551
3552<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3553<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3554 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3555 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3556
3557<h5>Semantics:</h5>
3558<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3559 significant bits of the result will be filled with zero bits after the shift.
3560 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3561 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3562 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3563 shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3564
3565<h5>Example:</h5>
3566<pre>
3567 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3568 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3569 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3570 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3571 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3572 &lt;result&gt; = lshr &lt;2 x i32&gt; &lt; i32 -2, i32 4&gt;, &lt; i32 1, i32 2&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 0x7FFFFFFF, i32 1&gt;</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3573</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3574
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3575</div>
3576
3577<!-- _______________________________________________________________________ -->
3578<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3579Instruction</a> </div>
3580<div class="doc_text">
3581
3582<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3583<pre>
3584 &lt;result&gt; = ashr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3585</pre>
3586
3587<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3588<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3589 operand shifted to the right a specified number of bits with sign
3590 extension.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3591
3592<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3593<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3594 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3595 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3596
3597<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3598<p>This instruction always performs an arithmetic shift right operation, The
3599 most significant bits of the result will be filled with the sign bit
3600 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3601 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3602 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3603 the corresponding shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3604
3605<h5>Example:</h5>
3606<pre>
3607 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3608 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3609 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3610 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3611 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3612 &lt;result&gt; = ashr &lt;2 x i32&gt; &lt; i32 -2, i32 4&gt;, &lt; i32 1, i32 3&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 -1, i32 0&gt;</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3613</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3614
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3615</div>
3616
3617<!-- _______________________________________________________________________ -->
3618<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3619Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3620
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3621<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3622
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3623<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3624<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3625 &lt;result&gt; = and &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3626</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3627
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3628<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3629<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3630 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3631
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3632<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3633<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3634 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3635 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3636
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3637<h5>Semantics:</h5>
3638<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3639
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3640<table border="1" cellspacing="0" cellpadding="4">
3641 <tbody>
3642 <tr>
3643 <td>In0</td>
3644 <td>In1</td>
3645 <td>Out</td>
3646 </tr>
3647 <tr>
3648 <td>0</td>
3649 <td>0</td>
3650 <td>0</td>
3651 </tr>
3652 <tr>
3653 <td>0</td>
3654 <td>1</td>
3655 <td>0</td>
3656 </tr>
3657 <tr>
3658 <td>1</td>
3659 <td>0</td>
3660 <td>0</td>
3661 </tr>
3662 <tr>
3663 <td>1</td>
3664 <td>1</td>
3665 <td>1</td>
3666 </tr>
3667 </tbody>
3668</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3669
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3670<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3671<pre>
3672 &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3673 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3674 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
3675</pre>
3676</div>
3677<!-- _______________________________________________________________________ -->
3678<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3679
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3680<div class="doc_text">
3681
3682<h5>Syntax:</h5>
3683<pre>
3684 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3685</pre>
3686
3687<h5>Overview:</h5>
3688<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3689 two operands.</p>
3690
3691<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3692<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3693 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3694 values. Both arguments must have identical types.</p>
3695
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3696<h5>Semantics:</h5>
3697<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3698
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3699<table border="1" cellspacing="0" cellpadding="4">
3700 <tbody>
3701 <tr>
3702 <td>In0</td>
3703 <td>In1</td>
3704 <td>Out</td>
3705 </tr>
3706 <tr>
3707 <td>0</td>
3708 <td>0</td>
3709 <td>0</td>
3710 </tr>
3711 <tr>
3712 <td>0</td>
3713 <td>1</td>
3714 <td>1</td>
3715 </tr>
3716 <tr>
3717 <td>1</td>
3718 <td>0</td>
3719 <td>1</td>
3720 </tr>
3721 <tr>
3722 <td>1</td>
3723 <td>1</td>
3724 <td>1</td>
3725 </tr>
3726 </tbody>
3727</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3728
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3729<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3730<pre>
3731 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3732 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3733 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
3734</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3735
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3736</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3737
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3738<!-- _______________________________________________________________________ -->
3739<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3740Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3741
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3742<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3743
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3744<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3745<pre>
3746 &lt;result&gt; = xor &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3747</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3748
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3749<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3750<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3751 its two operands. The <tt>xor</tt> is used to implement the "one's
3752 complement" operation, which is the "~" operator in C.</p>
3753
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3754<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3755<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3756 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3757 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3758
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3759<h5>Semantics:</h5>
3760<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3761
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3762<table border="1" cellspacing="0" cellpadding="4">
3763 <tbody>
3764 <tr>
3765 <td>In0</td>
3766 <td>In1</td>
3767 <td>Out</td>
3768 </tr>
3769 <tr>
3770 <td>0</td>
3771 <td>0</td>
3772 <td>0</td>
3773 </tr>
3774 <tr>
3775 <td>0</td>
3776 <td>1</td>
3777 <td>1</td>
3778 </tr>
3779 <tr>
3780 <td>1</td>
3781 <td>0</td>
3782 <td>1</td>
3783 </tr>
3784 <tr>
3785 <td>1</td>
3786 <td>1</td>
3787 <td>0</td>
3788 </tr>
3789 </tbody>
3790</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3791
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3792<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3793<pre>
3794 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3795 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3796 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3797 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
3798</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3799
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3800</div>
3801
3802<!-- ======================================================================= -->
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3803<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3804 <a name="vectorops">Vector Operations</a>
3805</div>
3806
3807<div class="doc_text">
3808
3809<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3810 target-independent manner. These instructions cover the element-access and
3811 vector-specific operations needed to process vectors effectively. While LLVM
3812 does directly support these vector operations, many sophisticated algorithms
3813 will want to use target-specific intrinsics to take full advantage of a
3814 specific target.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3815
3816</div>
3817
3818<!-- _______________________________________________________________________ -->
3819<div class="doc_subsubsection">
3820 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3821</div>
3822
3823<div class="doc_text">
3824
3825<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3826<pre>
3827 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
3828</pre>
3829
3830<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3831<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3832 from a vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3833
3834
3835<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3836<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3837 of <a href="#t_vector">vector</a> type. The second operand is an index
3838 indicating the position from which to extract the element. The index may be
3839 a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3840
3841<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3842<p>The result is a scalar of the same type as the element type of
3843 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3844 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3845 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3846
3847<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3848<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]3849 &lt;result&gt; = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3850</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3851
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3852</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3853
3854<!-- _______________________________________________________________________ -->
3855<div class="doc_subsubsection">
3856 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3857</div>
3858
3859<div class="doc_text">
3860
3861<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3862<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]3863 &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>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3864</pre>
3865
3866<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3867<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
3868 vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3869
3870<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3871<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
3872 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
3873 whose type must equal the element type of the first operand. The third
3874 operand is an index indicating the position at which to insert the value.
3875 The index may be a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3876
3877<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3878<p>The result is a vector of the same type as <tt>val</tt>. Its element values
3879 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
3880 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3881 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3882
3883<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3884<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]3885 &lt;result&gt; = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3886</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3887
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3888</div>
3889
3890<!-- _______________________________________________________________________ -->
3891<div class="doc_subsubsection">
3892 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3893</div>
3894
3895<div class="doc_text">
3896
3897<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3898<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3899 &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;m x i32&gt; &lt;mask&gt; <i>; yields &lt;m x &lt;ty&gt;&gt;</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3900</pre>
3901
3902<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3903<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
3904 from two input vectors, returning a vector with the same element type as the
3905 input and length that is the same as the shuffle mask.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3906
3907<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3908<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3909 with types that match each other. The third argument is a shuffle mask whose
3910 element type is always 'i32'. The result of the instruction is a vector
3911 whose length is the same as the shuffle mask and whose element type is the
3912 same as the element type of the first two operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3913
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3914<p>The shuffle mask operand is required to be a constant vector with either
3915 constant integer or undef values.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3916
3917<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3918<p>The elements of the two input vectors are numbered from left to right across
3919 both of the vectors. The shuffle mask operand specifies, for each element of
3920 the result vector, which element of the two input vectors the result element
3921 gets. The element selector may be undef (meaning "don't care") and the
3922 second operand may be undef if performing a shuffle from only one vector.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3923
3924<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3925<pre>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3926 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3927 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3928 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3929 &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.
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3930 &lt;result&gt; = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3931 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3932 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3933 &lt;8 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7 &gt; <i>; yields &lt;8 x i32&gt;</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3934</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3935
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3936</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3937
3938<!-- ======================================================================= -->
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3939<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3940 <a name="aggregateops">Aggregate Operations</a>
3941</div>
3942
3943<div class="doc_text">
3944
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]3945<p>LLVM supports several instructions for working with
3946 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3947
3948</div>
3949
3950<!-- _______________________________________________________________________ -->
3951<div class="doc_subsubsection">
3952 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3953</div>
3954
3955<div class="doc_text">
3956
3957<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3958<pre>
3959 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3960</pre>
3961
3962<h5>Overview:</h5>
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]3963<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
3964 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3965
3966<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3967<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]3968 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
3969 <a href="#t_array">array</a> type. The operands are constant indices to
3970 specify which value to extract in a similar manner as indices in a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3971 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3972
3973<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3974<p>The result is the value at the position in the aggregate specified by the
3975 index operands.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3976
3977<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3978<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]3979 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3980</pre>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3981
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3982</div>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3983
3984<!-- _______________________________________________________________________ -->
3985<div class="doc_subsubsection">
3986 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3987</div>
3988
3989<div class="doc_text">
3990
3991<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3992<pre>
Jeffrey Yasskine05d7732010-01-11 19:19:26 +0000[diff] [blame]3993 &lt;result&gt; = insertvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;ty&gt; &lt;elt&gt;, &lt;idx&gt; <i>; yields &lt;aggregate type&gt;</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3994</pre>
3995
3996<h5>Overview:</h5>
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]3997<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
3998 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3999
4000<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4001<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4002 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4003 <a href="#t_array">array</a> type. The second operand is a first-class
4004 value to insert. The following operands are constant indices indicating
4005 the position at which to insert the value in a similar manner as indices in a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4006 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
4007 value to insert must have the same type as the value identified by the
4008 indices.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4009
4010<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4011<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4012 that of <tt>val</tt> except that the value at the position specified by the
4013 indices is that of <tt>elt</tt>.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4014
4015<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4016<pre>
Jeffrey Yasskine05d7732010-01-11 19:19:26 +0000[diff] [blame]4017 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4018 %agg2 = insertvalue {i32, float} %agg1, float %val, 1 <i>; yields {i32 1, float %val}</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4019</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4020
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4021</div>
4022
4023
4024<!-- ======================================================================= -->
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4025<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4026 <a name="memoryops">Memory Access and Addressing Operations</a>
4027</div>
4028
4029<div class="doc_text">
4030
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4031<p>A key design point of an SSA-based representation is how it represents
4032 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]4033 very simple. This section describes how to read, write, and allocate
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4034 memory in LLVM.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4035
4036</div>
4037
4038<!-- _______________________________________________________________________ -->
4039<div class="doc_subsubsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4040 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4041</div>
4042
4043<div class="doc_text">
4044
4045<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4046<pre>
4047 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
4048</pre>
4049
4050<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4051<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4052 currently executing function, to be automatically released when this function
4053 returns to its caller. The object is always allocated in the generic address
4054 space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4055
4056<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4057<p>The '<tt>alloca</tt>' instruction
4058 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4059 runtime stack, returning a pointer of the appropriate type to the program.
4060 If "NumElements" is specified, it is the number of elements allocated,
4061 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4062 specified, the value result of the allocation is guaranteed to be aligned to
4063 at least that boundary. If not specified, or if zero, the target can choose
4064 to align the allocation on any convenient boundary compatible with the
4065 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4066
4067<p>'<tt>type</tt>' may be any sized type.</p>
4068
4069<h5>Semantics:</h5>
Bill Wendling2a454572009-05-08 20:49:29 +0000[diff] [blame]4070<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4071 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4072 memory is automatically released when the function returns. The
4073 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4074 variables that must have an address available. When the function returns
4075 (either with the <tt><a href="#i_ret">ret</a></tt>
4076 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4077 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4078
4079<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4080<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]4081 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4082 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4083 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4084 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4085</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4086
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4087</div>
4088
4089<!-- _______________________________________________________________________ -->
4090<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4091Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4092
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4093<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4094
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4095<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4096<pre>
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4097 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4098 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4099 !&lt;index&gt; = !{ i32 1 }
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4100</pre>
4101
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4102<h5>Overview:</h5>
4103<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4104
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4105<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4106<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4107 from which to load. The pointer must point to
4108 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4109 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
4110 number or order of execution of this <tt>load</tt> with other
4111 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4112 instructions.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4113
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4114<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4115 operation (that is, the alignment of the memory address). A value of 0 or an
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4116 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4117 alignment for the target. It is the responsibility of the code emitter to
4118 ensure that the alignment information is correct. Overestimating the
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4119 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4120 produce less efficient code. An alignment of 1 is always safe.</p>
4121
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4122<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4123 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]4124 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4125 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4126 and code generator that this load is not expected to be reused in the cache.
4127 The code generator may select special instructions to save cache bandwidth,
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]4128 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4129
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4130<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4131<p>The location of memory pointed to is loaded. If the value being loaded is of
4132 scalar type then the number of bytes read does not exceed the minimum number
4133 of bytes needed to hold all bits of the type. For example, loading an
4134 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4135 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4136 is undefined if the value was not originally written using a store of the
4137 same type.</p>
4138
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4139<h5>Examples:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4140<pre>
4141 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4142 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4143 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
4144</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4145
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4146</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4147
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4148<!-- _______________________________________________________________________ -->
4149<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4150Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4151
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4152<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4153
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4154<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4155<pre>
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4156 store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !<index>] <i>; yields {void}</i>
4157 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !<index>] <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4158</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4159
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4160<h5>Overview:</h5>
4161<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4162
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4163<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4164<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4165 and an address at which to store it. The type of the
4166 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4167 the <a href="#t_firstclass">first class</a> type of the
4168 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked
4169 as <tt>volatile</tt>, then the optimizer is not allowed to modify the number
4170 or order of execution of this <tt>store</tt> with other
4171 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
4172 instructions.</p>
4173
4174<p>The optional constant "align" argument specifies the alignment of the
4175 operation (that is, the alignment of the memory address). A value of 0 or an
4176 omitted "align" argument means that the operation has the preferential
4177 alignment for the target. It is the responsibility of the code emitter to
4178 ensure that the alignment information is correct. Overestimating the
4179 alignment results in an undefined behavior. Underestimating the alignment may
4180 produce less efficient code. An alignment of 1 is always safe.</p>
4181
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4182<p>The optional !nontemporal metadata must reference a single metatadata
4183 name <index> corresponding to a metadata node with one i32 entry of
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]4184 value 1. The existence of the !nontemporal metatadata on the
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4185 instruction tells the optimizer and code generator that this load is
4186 not expected to be reused in the cache. The code generator may
4187 select special instructions to save cache bandwidth, such as the
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]4188 MOVNT instruction on x86.</p>
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4189
4190
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4191<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4192<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4193 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4194 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4195 does not exceed the minimum number of bytes needed to hold all bits of the
4196 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4197 writing a value of a type like <tt>i20</tt> with a size that is not an
4198 integral number of bytes, it is unspecified what happens to the extra bits
4199 that do not belong to the type, but they will typically be overwritten.</p>
4200
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4201<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4202<pre>
4203 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]4204 store i32 3, i32* %ptr <i>; yields {void}</i>
4205 %val = <a href="#i_load">load</a> i32* %ptr <i>; yields {i32}:val = i32 3</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4206</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4207
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4208</div>
4209
4210<!-- _______________________________________________________________________ -->
4211<div class="doc_subsubsection">
4212 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4213</div>
4214
4215<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4216
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4217<h5>Syntax:</h5>
4218<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4219 &lt;result&gt; = getelementptr &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4220 &lt;result&gt; = getelementptr inbounds &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4221</pre>
4222
4223<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4224<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4225 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4226 It performs address calculation only and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4227
4228<h5>Arguments:</h5>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4229<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnere92fc832009-07-29 06:44:13 +0000[diff] [blame]4230 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4231 elements of the aggregate object are indexed. The interpretation of each
4232 index is dependent on the type being indexed into. The first index always
4233 indexes the pointer value given as the first argument, the second index
4234 indexes a value of the type pointed to (not necessarily the value directly
4235 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4236 indexed into must be a pointer value, subsequent types can be arrays,
4237 vectors, structs and unions. Note that subsequent types being indexed into
4238 can never be pointers, since that would require loading the pointer before
4239 continuing calculation.</p>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4240
4241<p>The type of each index argument depends on the type it is indexing into.
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4242 When indexing into a (optionally packed) structure or union, only <tt>i32</tt>
4243 integer <b>constants</b> are allowed. When indexing into an array, pointer
4244 or vector, integers of any width are allowed, and they are not required to be
Chris Lattnere92fc832009-07-29 06:44:13 +0000[diff] [blame]4245 constant.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4246
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4247<p>For example, let's consider a C code fragment and how it gets compiled to
4248 LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4249
4250<div class="doc_code">
4251<pre>
4252struct RT {
4253 char A;
4254 int B[10][20];
4255 char C;
4256};
4257struct ST {
4258 int X;
4259 double Y;
4260 struct RT Z;
4261};
4262
4263int *foo(struct ST *s) {
4264 return &amp;s[1].Z.B[5][13];
4265}
4266</pre>
4267</div>
4268
4269<p>The LLVM code generated by the GCC frontend is:</p>
4270
4271<div class="doc_code">
4272<pre>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]4273%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4274%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4275
Dan Gohman47360842009-07-25 02:23:48 +0000[diff] [blame]4276define i32* @foo(%ST* %s) {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4277entry:
4278 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4279 ret i32* %reg
4280}
4281</pre>
4282</div>
4283
4284<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4285<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4286 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4287 }</tt>' type, a structure. The second index indexes into the third element
4288 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4289 i8 }</tt>' type, another structure. The third index indexes into the second
4290 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4291 array. The two dimensions of the array are subscripted into, yielding an
4292 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4293 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4294
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4295<p>Note that it is perfectly legal to index partially through a structure,
4296 returning a pointer to an inner element. Because of this, the LLVM code for
4297 the given testcase is equivalent to:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4298
4299<pre>
Dan Gohman47360842009-07-25 02:23:48 +0000[diff] [blame]4300 define i32* @foo(%ST* %s) {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4301 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
4302 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4303 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
4304 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4305 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4306 ret i32* %t5
4307 }
4308</pre>
4309
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4310<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman4cba1562009-07-29 16:00:30 +0000[diff] [blame]4311 <tt>getelementptr</tt> is undefined if the base pointer is not an
4312 <i>in bounds</i> address of an allocated object, or if any of the addresses
Dan Gohmanbc4c87f2009-08-20 17:08:17 +0000[diff] [blame]4313 that would be formed by successive addition of the offsets implied by the
4314 indices to the base address with infinitely precise arithmetic are not an
4315 <i>in bounds</i> address of that allocated object.
Dan Gohman4cba1562009-07-29 16:00:30 +0000[diff] [blame]4316 The <i>in bounds</i> addresses for an allocated object are all the addresses
Dan Gohmanbc4c87f2009-08-20 17:08:17 +0000[diff] [blame]4317 that point into the object, plus the address one byte past the end.</p>
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4318
4319<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4320 the base address with silently-wrapping two's complement arithmetic, and
4321 the result value of the <tt>getelementptr</tt> may be outside the object
4322 pointed to by the base pointer. The result value may not necessarily be
4323 used to access memory though, even if it happens to point into allocated
4324 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4325 section for more information.</p>
4326
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4327<p>The getelementptr instruction is often confusing. For some more insight into
4328 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4329
4330<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4331<pre>
4332 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4333 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4334 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4335 %vptr = getelementptr {i32, &lt;2 x i8&gt;}* %svptr, i64 0, i32 1, i32 1
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4336 <i>; yields i8*:eptr</i>
4337 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta4f9a0dc2009-04-25 07:27:44 +0000[diff] [blame]4338 <i>; yields i32*:iptr</i>
Sanjiv Gupta1e46c582009-04-24 16:38:13 +0000[diff] [blame]4339 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4340</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4341
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4342</div>
4343
4344<!-- ======================================================================= -->
4345<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
4346</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4347
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4348<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4349
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4350<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4351 which all take a single operand and a type. They perform various bit
4352 conversions on the operand.</p>
4353
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4354</div>
4355
4356<!-- _______________________________________________________________________ -->
4357<div class="doc_subsubsection">
4358 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4359</div>
4360<div class="doc_text">
4361
4362<h5>Syntax:</h5>
4363<pre>
4364 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4365</pre>
4366
4367<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4368<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4369 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4370
4371<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4372<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4373 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4374 size and type of the result, which must be
4375 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4376 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4377 allowed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4378
4379<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4380<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4381 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4382 source size must be larger than the destination size, <tt>trunc</tt> cannot
4383 be a <i>no-op cast</i>. It will always truncate bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4384
4385<h5>Example:</h5>
4386<pre>
4387 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
4388 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4389 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4390</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4391
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4392</div>
4393
4394<!-- _______________________________________________________________________ -->
4395<div class="doc_subsubsection">
4396 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4397</div>
4398<div class="doc_text">
4399
4400<h5>Syntax:</h5>
4401<pre>
4402 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4403</pre>
4404
4405<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4406<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4407 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4408
4409
4410<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4411<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4412 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4413 also be of <a href="#t_integer">integer</a> type. The bit size of the
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4414 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4415 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4416
4417<h5>Semantics:</h5>
4418<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4419 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4420
4421<p>When zero extending from i1, the result will always be either 0 or 1.</p>
4422
4423<h5>Example:</h5>
4424<pre>
4425 %X = zext i32 257 to i64 <i>; yields i64:257</i>
4426 %Y = zext i1 true to i32 <i>; yields i32:1</i>
4427</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4428
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4429</div>
4430
4431<!-- _______________________________________________________________________ -->
4432<div class="doc_subsubsection">
4433 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4434</div>
4435<div class="doc_text">
4436
4437<h5>Syntax:</h5>
4438<pre>
4439 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4440</pre>
4441
4442<h5>Overview:</h5>
4443<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4444
4445<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4446<p>The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4447 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4448 also be of <a href="#t_integer">integer</a> type. The bit size of the
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4449 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4450 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4451
4452<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4453<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4454 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4455 of the type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4456
4457<p>When sign extending from i1, the extension always results in -1 or 0.</p>
4458
4459<h5>Example:</h5>
4460<pre>
4461 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
4462 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
4463</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4464
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4465</div>
4466
4467<!-- _______________________________________________________________________ -->
4468<div class="doc_subsubsection">
4469 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4470</div>
4471
4472<div class="doc_text">
4473
4474<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4475<pre>
4476 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4477</pre>
4478
4479<h5>Overview:</h5>
4480<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4481 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4482
4483<h5>Arguments:</h5>
4484<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4485 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4486 to cast it to. The size of <tt>value</tt> must be larger than the size of
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4487 <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4488 <i>no-op cast</i>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4489
4490<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4491<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4492 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4493 <a href="#t_floating">floating point</a> type. If the value cannot fit
4494 within the destination type, <tt>ty2</tt>, then the results are
4495 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4496
4497<h5>Example:</h5>
4498<pre>
4499 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4500 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4501</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4502
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4503</div>
4504
4505<!-- _______________________________________________________________________ -->
4506<div class="doc_subsubsection">
4507 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4508</div>
4509<div class="doc_text">
4510
4511<h5>Syntax:</h5>
4512<pre>
4513 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4514</pre>
4515
4516<h5>Overview:</h5>
4517<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4518 floating point value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4519
4520<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4521<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4522 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4523 a <a href="#t_floating">floating point</a> type to cast it to. The source
4524 type must be smaller than the destination type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4525
4526<h5>Semantics:</h5>
4527<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4528 <a href="#t_floating">floating point</a> type to a larger
4529 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4530 used to make a <i>no-op cast</i> because it always changes bits. Use
4531 <tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4532
4533<h5>Example:</h5>
4534<pre>
4535 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4536 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4537</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4538
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4539</div>
4540
4541<!-- _______________________________________________________________________ -->
4542<div class="doc_subsubsection">
4543 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
4544</div>
4545<div class="doc_text">
4546
4547<h5>Syntax:</h5>
4548<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4549 &lt;result&gt; = fptoui &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4550</pre>
4551
4552<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4553<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4554 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4555
4556<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4557<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4558 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4559 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4560 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4561 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4562
4563<h5>Semantics:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4564<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4565 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4566 towards zero) unsigned integer value. If the value cannot fit
4567 in <tt>ty2</tt>, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4568
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4569<h5>Example:</h5>
4570<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4571 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4572 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4573 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4574</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4575
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4576</div>
4577
4578<!-- _______________________________________________________________________ -->
4579<div class="doc_subsubsection">
4580 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
4581</div>
4582<div class="doc_text">
4583
4584<h5>Syntax:</h5>
4585<pre>
4586 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4587</pre>
4588
4589<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4590<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4591 <a href="#t_floating">floating point</a> <tt>value</tt> to
4592 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4593
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4594<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4595<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4596 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4597 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4598 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4599 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4600
4601<h5>Semantics:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4602<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4603 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4604 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4605 the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4606
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4607<h5>Example:</h5>
4608<pre>
4609 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4610 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4611 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4612</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4613
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4614</div>
4615
4616<!-- _______________________________________________________________________ -->
4617<div class="doc_subsubsection">
4618 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
4619</div>
4620<div class="doc_text">
4621
4622<h5>Syntax:</h5>
4623<pre>
4624 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4625</pre>
4626
4627<h5>Overview:</h5>
4628<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4629 integer and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4630
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4631<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4632<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4633 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4634 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4635 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4636 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4637
4638<h5>Semantics:</h5>
4639<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4640 integer quantity and converts it to the corresponding floating point
4641 value. If the value cannot fit in the floating point value, the results are
4642 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4643
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4644<h5>Example:</h5>
4645<pre>
4646 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4647 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4648</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4649
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4650</div>
4651
4652<!-- _______________________________________________________________________ -->
4653<div class="doc_subsubsection">
4654 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
4655</div>
4656<div class="doc_text">
4657
4658<h5>Syntax:</h5>
4659<pre>
4660 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4661</pre>
4662
4663<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4664<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4665 and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4666
4667<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4668<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4669 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4670 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4671 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4672 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4673
4674<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4675<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4676 quantity and converts it to the corresponding floating point value. If the
4677 value cannot fit in the floating point value, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4678
4679<h5>Example:</h5>
4680<pre>
4681 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4682 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4683</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4684
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4685</div>
4686
4687<!-- _______________________________________________________________________ -->
4688<div class="doc_subsubsection">
4689 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4690</div>
4691<div class="doc_text">
4692
4693<h5>Syntax:</h5>
4694<pre>
4695 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4696</pre>
4697
4698<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4699<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4700 the integer type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4701
4702<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4703<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4704 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4705 <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4706
4707<h5>Semantics:</h5>
4708<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4709 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4710 truncating or zero extending that value to the size of the integer type. If
4711 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4712 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4713 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4714 change.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4715
4716<h5>Example:</h5>
4717<pre>
4718 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4719 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
4720</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4721
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4722</div>
4723
4724<!-- _______________________________________________________________________ -->
4725<div class="doc_subsubsection">
4726 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4727</div>
4728<div class="doc_text">
4729
4730<h5>Syntax:</h5>
4731<pre>
4732 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4733</pre>
4734
4735<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4736<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4737 pointer type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4738
4739<h5>Arguments:</h5>
4740<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4741 value to cast, and a type to cast it to, which must be a
4742 <a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4743
4744<h5>Semantics:</h5>
4745<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4746 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4747 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4748 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4749 than the size of a pointer then a zero extension is done. If they are the
4750 same size, nothing is done (<i>no-op cast</i>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4751
4752<h5>Example:</h5>
4753<pre>
4754 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4755 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4756 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4757</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4758
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4759</div>
4760
4761<!-- _______________________________________________________________________ -->
4762<div class="doc_subsubsection">
4763 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
4764</div>
4765<div class="doc_text">
4766
4767<h5>Syntax:</h5>
4768<pre>
4769 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4770</pre>
4771
4772<h5>Overview:</h5>
4773<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4774 <tt>ty2</tt> without changing any bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4775
4776<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4777<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4778 non-aggregate first class value, and a type to cast it to, which must also be
4779 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4780 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4781 identical. If the source type is a pointer, the destination type must also be
4782 a pointer. This instruction supports bitwise conversion of vectors to
4783 integers and to vectors of other types (as long as they have the same
4784 size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4785
4786<h5>Semantics:</h5>
4787<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4788 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4789 this conversion. The conversion is done as if the <tt>value</tt> had been
4790 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4791 be converted to other pointer types with this instruction. To convert
4792 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4793 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4794
4795<h5>Example:</h5>
4796<pre>
4797 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
4798 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4799 %Z = bitcast &lt;2 x int&gt; %V to i64; <i>; yields i64: %V</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4800</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4801
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4802</div>
4803
4804<!-- ======================================================================= -->
4805<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4806
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4807<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4808
4809<p>The instructions in this category are the "miscellaneous" instructions, which
4810 defy better classification.</p>
4811
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4812</div>
4813
4814<!-- _______________________________________________________________________ -->
4815<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4816</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4817
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4818<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4819
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4820<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4821<pre>
4822 &lt;result&gt; = icmp &lt;cond&gt; &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {i1} or {&lt;N x i1&gt;}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4823</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4824
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4825<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4826<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4827 boolean values based on comparison of its two integer, integer vector, or
4828 pointer operands.</p>
4829
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4830<h5>Arguments:</h5>
4831<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4832 the condition code indicating the kind of comparison to perform. It is not a
4833 value, just a keyword. The possible condition code are:</p>
4834
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4835<ol>
4836 <li><tt>eq</tt>: equal</li>
4837 <li><tt>ne</tt>: not equal </li>
4838 <li><tt>ugt</tt>: unsigned greater than</li>
4839 <li><tt>uge</tt>: unsigned greater or equal</li>
4840 <li><tt>ult</tt>: unsigned less than</li>
4841 <li><tt>ule</tt>: unsigned less or equal</li>
4842 <li><tt>sgt</tt>: signed greater than</li>
4843 <li><tt>sge</tt>: signed greater or equal</li>
4844 <li><tt>slt</tt>: signed less than</li>
4845 <li><tt>sle</tt>: signed less or equal</li>
4846</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4847
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4848<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4849 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
4850 typed. They must also be identical types.</p>
4851
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4852<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4853<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
4854 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]4855 either an <a href="#t_integer"><tt>i1</tt></a> or vector of <tt>i1</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4856 result, as follows:</p>
4857
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4858<ol>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4859 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4860 <tt>false</tt> otherwise. No sign interpretation is necessary or
4861 performed.</li>
4862
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4863 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4864 <tt>false</tt> otherwise. No sign interpretation is necessary or
4865 performed.</li>
4866
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4867 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4868 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4869
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4870 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4871 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4872 to <tt>op2</tt>.</li>
4873
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4874 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4875 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4876
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4877 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4878 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4879
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4880 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4881 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4882
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4883 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4884 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4885 to <tt>op2</tt>.</li>
4886
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4887 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4888 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4889
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4890 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4891 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4892</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4893
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4894<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4895 values are compared as if they were integers.</p>
4896
4897<p>If the operands are integer vectors, then they are compared element by
4898 element. The result is an <tt>i1</tt> vector with the same number of elements
4899 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4900
4901<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4902<pre>
4903 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4904 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4905 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4906 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4907 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4908 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
4909</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4910
4911<p>Note that the code generator does not yet support vector types with
4912 the <tt>icmp</tt> instruction.</p>
4913
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4914</div>
4915
4916<!-- _______________________________________________________________________ -->
4917<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4918</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4919
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4920<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4921
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4922<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4923<pre>
4924 &lt;result&gt; = fcmp &lt;cond&gt; &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {i1} or {&lt;N x i1&gt;}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4925</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4926
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4927<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4928<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
4929 values based on comparison of its operands.</p>
4930
4931<p>If the operands are floating point scalars, then the result type is a boolean
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]4932(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4933
4934<p>If the operands are floating point vectors, then the result type is a vector
4935 of boolean with the same number of elements as the operands being
4936 compared.</p>
4937
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4938<h5>Arguments:</h5>
4939<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4940 the condition code indicating the kind of comparison to perform. It is not a
4941 value, just a keyword. The possible condition code are:</p>
4942
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4943<ol>
4944 <li><tt>false</tt>: no comparison, always returns false</li>
4945 <li><tt>oeq</tt>: ordered and equal</li>
4946 <li><tt>ogt</tt>: ordered and greater than </li>
4947 <li><tt>oge</tt>: ordered and greater than or equal</li>
4948 <li><tt>olt</tt>: ordered and less than </li>
4949 <li><tt>ole</tt>: ordered and less than or equal</li>
4950 <li><tt>one</tt>: ordered and not equal</li>
4951 <li><tt>ord</tt>: ordered (no nans)</li>
4952 <li><tt>ueq</tt>: unordered or equal</li>
4953 <li><tt>ugt</tt>: unordered or greater than </li>
4954 <li><tt>uge</tt>: unordered or greater than or equal</li>
4955 <li><tt>ult</tt>: unordered or less than </li>
4956 <li><tt>ule</tt>: unordered or less than or equal</li>
4957 <li><tt>une</tt>: unordered or not equal</li>
4958 <li><tt>uno</tt>: unordered (either nans)</li>
4959 <li><tt>true</tt>: no comparison, always returns true</li>
4960</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4961
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4962<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4963 <i>unordered</i> means that either operand may be a QNAN.</p>
4964
4965<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
4966 a <a href="#t_floating">floating point</a> type or
4967 a <a href="#t_vector">vector</a> of floating point type. They must have
4968 identical types.</p>
4969
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4970<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4971<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4972 according to the condition code given as <tt>cond</tt>. If the operands are
4973 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]4974 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4975 follows:</p>
4976
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4977<ol>
4978 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4979
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4980 <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4981 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4982
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4983 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]4984 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4985
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4986 <li><tt>oge</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4987 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4988
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4989 <li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4990 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4991
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4992 <li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4993 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4994
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4995 <li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4996 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4997
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4998 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4999
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5000 <li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5001 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5002
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5003 <li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5004 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5005
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5006 <li><tt>uge</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5007 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5008
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5009 <li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5010 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5011
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5012 <li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5013 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5014
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5015 <li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5016 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5017
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5018 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5019
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5020 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5021</ol>
5022
5023<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5024<pre>
5025 &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]5026 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5027 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5028 &lt;result&gt; = fcmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5029</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]5030
5031<p>Note that the code generator does not yet support vector types with
5032 the <tt>fcmp</tt> instruction.</p>
5033
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5034</div>
5035
5036<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]5037<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5038 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5039</div>
5040
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5041<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5042
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5043<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5044<pre>
5045 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5046</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5047
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5048<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5049<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5050 SSA graph representing the function.</p>
5051
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5052<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5053<p>The type of the incoming values is specified with the first type field. After
5054 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5055 one pair for each predecessor basic block of the current block. Only values
5056 of <a href="#t_firstclass">first class</a> type may be used as the value
5057 arguments to the PHI node. Only labels may be used as the label
5058 arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5059
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5060<p>There must be no non-phi instructions between the start of a basic block and
5061 the PHI instructions: i.e. PHI instructions must be first in a basic
5062 block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5063
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5064<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5065 occur on the edge from the corresponding predecessor block to the current
5066 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5067 value on the same edge).</p>
Jay Foad8e2fd2c2009-06-03 10:20:10 +0000[diff] [blame]5068
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5069<h5>Semantics:</h5>
5070<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5071 specified by the pair corresponding to the predecessor basic block that
5072 executed just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5073
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5074<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5075<pre>
5076Loop: ; Infinite loop that counts from 0 on up...
5077 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5078 %nextindvar = add i32 %indvar, 1
5079 br label %Loop
5080</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5081
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5082</div>
5083
5084<!-- _______________________________________________________________________ -->
5085<div class="doc_subsubsection">
5086 <a name="i_select">'<tt>select</tt>' Instruction</a>
5087</div>
5088
5089<div class="doc_text">
5090
5091<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5092<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]5093 &lt;result&gt; = select <i>selty</i> &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
5094
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5095 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5096</pre>
5097
5098<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5099<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5100 condition, without branching.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5101
5102
5103<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5104<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5105 values indicating the condition, and two values of the
5106 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5107 vectors and the condition is a scalar, then entire vectors are selected, not
5108 individual elements.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5109
5110<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5111<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5112 first value argument; otherwise, it returns the second value argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5113
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5114<p>If the condition is a vector of i1, then the value arguments must be vectors
5115 of the same size, and the selection is done element by element.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5116
5117<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5118<pre>
5119 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
5120</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]5121
5122<p>Note that the code generator does not yet support conditions
5123 with vector type.</p>
5124
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5125</div>
5126
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5127<!-- _______________________________________________________________________ -->
5128<div class="doc_subsubsection">
5129 <a name="i_call">'<tt>call</tt>' Instruction</a>
5130</div>
5131
5132<div class="doc_text">
5133
5134<h5>Syntax:</h5>
5135<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]5136 &lt;result&gt; = [tail] call [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>] &lt;ty&gt; [&lt;fnty&gt;*] &lt;fnptrval&gt;(&lt;function args&gt;) [<a href="#fnattrs">fn attrs</a>]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5137</pre>
5138
5139<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5140<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
5141
5142<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5143<p>This instruction requires several arguments:</p>
5144
5145<ol>
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]5146 <li>The optional "tail" marker indicates that the callee function does not
5147 access any allocas or varargs in the caller. Note that calls may be
5148 marked "tail" even if they do not occur before
5149 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5150 present, the function call is eligible for tail call optimization,
5151 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
5152 optimized into a jump</a>. As of this writing, the extra requirements for
5153 a call to actually be optimized are:
5154 <ul>
5155 <li>Caller and callee both have the calling
5156 convention <tt>fastcc</tt>.</li>
5157 <li>The call is in tail position (ret immediately follows call and ret
5158 uses value of call or is void).</li>
5159 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohman1be84f02010-03-02 01:08:11 +0000[diff] [blame]5160 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]5161 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5162 constraints are met.</a></li>
5163 </ul>
5164 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5165
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5166 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5167 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]5168 defaults to using C calling conventions. The calling convention of the
5169 call must match the calling convention of the target function, or else the
5170 behavior is undefined.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5171
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5172 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5173 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5174 '<tt>inreg</tt>' attributes are valid here.</li>
5175
5176 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5177 type of the return value. Functions that return no value are marked
5178 <tt><a href="#t_void">void</a></tt>.</li>
5179
5180 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5181 being invoked. The argument types must match the types implied by this
5182 signature. This type can be omitted if the function is not varargs and if
5183 the function type does not return a pointer to a function.</li>
5184
5185 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5186 be invoked. In most cases, this is a direct function invocation, but
5187 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5188 to function value.</li>
5189
5190 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner553fb1e2010-03-02 06:36:51 +0000[diff] [blame]5191 signature argument types and parameter attributes. All arguments must be
5192 of <a href="#t_firstclass">first class</a> type. If the function
5193 signature indicates the function accepts a variable number of arguments,
5194 the extra arguments can be specified.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5195
5196 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5197 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5198 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5199</ol>
5200
5201<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5202<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5203 a specified function, with its incoming arguments bound to the specified
5204 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5205 function, control flow continues with the instruction after the function
5206 call, and the return value of the function is bound to the result
5207 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5208
5209<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5210<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]5211 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]5212 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
5213 %X = tail call i32 @foo() <i>; yields i32</i>
5214 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5215 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]5216
5217 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5218 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]5219 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5220 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +0000[diff] [blame]5221 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +0000[diff] [blame]5222 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5223</pre>
5224
Dale Johannesen9fcf4a92009-09-24 18:38:21 +0000[diff] [blame]5225<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen4730cd32009-09-25 17:04:42 +0000[diff] [blame]5226standard C99 library as being the C99 library functions, and may perform
5227optimizations or generate code for them under that assumption. This is
5228something we'd like to change in the future to provide better support for
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]5229freestanding environments and non-C-based languages.</p>
Dale Johannesen9fcf4a92009-09-24 18:38:21 +0000[diff] [blame]5230
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5231</div>
5232
5233<!-- _______________________________________________________________________ -->
5234<div class="doc_subsubsection">
5235 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
5236</div>
5237
5238<div class="doc_text">
5239
5240<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5241<pre>
5242 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
5243</pre>
5244
5245<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5246<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5247 the "variable argument" area of a function call. It is used to implement the
5248 <tt>va_arg</tt> macro in C.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5249
5250<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5251<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5252 argument. It returns a value of the specified argument type and increments
5253 the <tt>va_list</tt> to point to the next argument. The actual type
5254 of <tt>va_list</tt> is target specific.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5255
5256<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5257<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5258 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5259 to the next argument. For more information, see the variable argument
5260 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5261
5262<p>It is legal for this instruction to be called in a function which does not
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5263 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5264 function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5265
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5266<p><tt>va_arg</tt> is an LLVM instruction instead of
5267 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5268 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5269
5270<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5271<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5272
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5273<p>Note that the code generator does not yet fully support va_arg on many
5274 targets. Also, it does not currently support va_arg with aggregate types on
5275 any target.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]5276
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5277</div>
5278
5279<!-- *********************************************************************** -->
5280<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5281<!-- *********************************************************************** -->
5282
5283<div class="doc_text">
5284
5285<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5286 well known names and semantics and are required to follow certain
5287 restrictions. Overall, these intrinsics represent an extension mechanism for
5288 the LLVM language that does not require changing all of the transformations
5289 in LLVM when adding to the language (or the bitcode reader/writer, the
5290 parser, etc...).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5291
5292<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5293 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5294 begin with this prefix. Intrinsic functions must always be external
5295 functions: you cannot define the body of intrinsic functions. Intrinsic
5296 functions may only be used in call or invoke instructions: it is illegal to
5297 take the address of an intrinsic function. Additionally, because intrinsic
5298 functions are part of the LLVM language, it is required if any are added that
5299 they be documented here.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5300
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5301<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5302 family of functions that perform the same operation but on different data
5303 types. Because LLVM can represent over 8 million different integer types,
5304 overloading is used commonly to allow an intrinsic function to operate on any
5305 integer type. One or more of the argument types or the result type can be
5306 overloaded to accept any integer type. Argument types may also be defined as
5307 exactly matching a previous argument's type or the result type. This allows
5308 an intrinsic function which accepts multiple arguments, but needs all of them
5309 to be of the same type, to only be overloaded with respect to a single
5310 argument or the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5311
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5312<p>Overloaded intrinsics will have the names of its overloaded argument types
5313 encoded into its function name, each preceded by a period. Only those types
5314 which are overloaded result in a name suffix. Arguments whose type is matched
5315 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5316 can take an integer of any width and returns an integer of exactly the same
5317 integer width. This leads to a family of functions such as
5318 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5319 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5320 suffix is required. Because the argument's type is matched against the return
5321 type, it does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5322
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5323<p>To learn how to add an intrinsic function, please see the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5324 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5325
5326</div>
5327
5328<!-- ======================================================================= -->
5329<div class="doc_subsection">
5330 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5331</div>
5332
5333<div class="doc_text">
5334
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5335<p>Variable argument support is defined in LLVM with
5336 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5337 intrinsic functions. These functions are related to the similarly named
5338 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5339
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5340<p>All of these functions operate on arguments that use a target-specific value
5341 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5342 not define what this type is, so all transformations should be prepared to
5343 handle these functions regardless of the type used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5344
5345<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5346 instruction and the variable argument handling intrinsic functions are
5347 used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5348
5349<div class="doc_code">
5350<pre>
5351define i32 @test(i32 %X, ...) {
5352 ; Initialize variable argument processing
5353 %ap = alloca i8*
5354 %ap2 = bitcast i8** %ap to i8*
5355 call void @llvm.va_start(i8* %ap2)
5356
5357 ; Read a single integer argument
5358 %tmp = va_arg i8** %ap, i32
5359
5360 ; Demonstrate usage of llvm.va_copy and llvm.va_end
5361 %aq = alloca i8*
5362 %aq2 = bitcast i8** %aq to i8*
5363 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
5364 call void @llvm.va_end(i8* %aq2)
5365
5366 ; Stop processing of arguments.
5367 call void @llvm.va_end(i8* %ap2)
5368 ret i32 %tmp
5369}
5370
5371declare void @llvm.va_start(i8*)
5372declare void @llvm.va_copy(i8*, i8*)
5373declare void @llvm.va_end(i8*)
5374</pre>
5375</div>
5376
5377</div>
5378
5379<!-- _______________________________________________________________________ -->
5380<div class="doc_subsubsection">
5381 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
5382</div>
5383
5384
5385<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5386
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5387<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5388<pre>
5389 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5390</pre>
5391
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5392<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5393<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5394 for subsequent use by <tt><a href="#i_va_arg">va_arg</a></tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5395
5396<h5>Arguments:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5397<p>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5398
5399<h5>Semantics:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5400<p>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5401 macro available in C. In a target-dependent way, it initializes
5402 the <tt>va_list</tt> element to which the argument points, so that the next
5403 call to <tt>va_arg</tt> will produce the first variable argument passed to
5404 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5405 need to know the last argument of the function as the compiler can figure
5406 that out.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5407
5408</div>
5409
5410<!-- _______________________________________________________________________ -->
5411<div class="doc_subsubsection">
5412 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
5413</div>
5414
5415<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5416
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5417<h5>Syntax:</h5>
5418<pre>
5419 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5420</pre>
5421
5422<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5423<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5424 which has been initialized previously
5425 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5426 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5427
5428<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5429<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
5430
5431<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5432<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5433 macro available in C. In a target-dependent way, it destroys
5434 the <tt>va_list</tt> element to which the argument points. Calls
5435 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5436 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5437 with calls to <tt>llvm.va_end</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5438
5439</div>
5440
5441<!-- _______________________________________________________________________ -->
5442<div class="doc_subsubsection">
5443 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
5444</div>
5445
5446<div class="doc_text">
5447
5448<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5449<pre>
5450 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
5451</pre>
5452
5453<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5454<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5455 from the source argument list to the destination argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5456
5457<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5458<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5459 The second argument is a pointer to a <tt>va_list</tt> element to copy
5460 from.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5461
5462<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5463<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5464 macro available in C. In a target-dependent way, it copies the
5465 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5466 element. This intrinsic is necessary because
5467 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5468 arbitrarily complex and require, for example, memory allocation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5469
5470</div>
5471
5472<!-- ======================================================================= -->
5473<div class="doc_subsection">
5474 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5475</div>
5476
5477<div class="doc_text">
5478
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5479<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5480Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5481intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5482roots on the stack</a>, as well as garbage collector implementations that
5483require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5484barriers. Front-ends for type-safe garbage collected languages should generate
5485these intrinsics to make use of the LLVM garbage collectors. For more details,
5486see <a href="GarbageCollection.html">Accurate Garbage Collection with
5487LLVM</a>.</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5488
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5489<p>The garbage collection intrinsics only operate on objects in the generic
5490 address space (address space zero).</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5491
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5492</div>
5493
5494<!-- _______________________________________________________________________ -->
5495<div class="doc_subsubsection">
5496 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
5497</div>
5498
5499<div class="doc_text">
5500
5501<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5502<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5503 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5504</pre>
5505
5506<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5507<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5508 the code generator, and allows some metadata to be associated with it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5509
5510<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5511<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5512 root pointer. The second pointer (which must be either a constant or a
5513 global value address) contains the meta-data to be associated with the
5514 root.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5515
5516<h5>Semantics:</h5>
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]5517<p>At runtime, a call to this intrinsic stores a null pointer into the "ptrloc"
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5518 location. At compile-time, the code generator generates information to allow
5519 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5520 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5521 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5522
5523</div>
5524
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5525<!-- _______________________________________________________________________ -->
5526<div class="doc_subsubsection">
5527 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
5528</div>
5529
5530<div class="doc_text">
5531
5532<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5533<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5534 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5535</pre>
5536
5537<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5538<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5539 locations, allowing garbage collector implementations that require read
5540 barriers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5541
5542<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5543<p>The second argument is the address to read from, which should be an address
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5544 allocated from the garbage collector. The first object is a pointer to the
5545 start of the referenced object, if needed by the language runtime (otherwise
5546 null).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5547
5548<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5549<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5550 instruction, but may be replaced with substantially more complex code by the
5551 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5552 may only be used in a function which <a href="#gc">specifies a GC
5553 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5554
5555</div>
5556
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5557<!-- _______________________________________________________________________ -->
5558<div class="doc_subsubsection">
5559 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
5560</div>
5561
5562<div class="doc_text">
5563
5564<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5565<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5566 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5567</pre>
5568
5569<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5570<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5571 locations, allowing garbage collector implementations that require write
5572 barriers (such as generational or reference counting collectors).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5573
5574<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5575<p>The first argument is the reference to store, the second is the start of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5576 object to store it to, and the third is the address of the field of Obj to
5577 store to. If the runtime does not require a pointer to the object, Obj may
5578 be null.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5579
5580<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5581<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5582 instruction, but may be replaced with substantially more complex code by the
5583 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5584 may only be used in a function which <a href="#gc">specifies a GC
5585 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5586
5587</div>
5588
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5589<!-- ======================================================================= -->
5590<div class="doc_subsection">
5591 <a name="int_codegen">Code Generator Intrinsics</a>
5592</div>
5593
5594<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5595
5596<p>These intrinsics are provided by LLVM to expose special features that may
5597 only be implemented with code generator support.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5598
5599</div>
5600
5601<!-- _______________________________________________________________________ -->
5602<div class="doc_subsubsection">
5603 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
5604</div>
5605
5606<div class="doc_text">
5607
5608<h5>Syntax:</h5>
5609<pre>
5610 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
5611</pre>
5612
5613<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5614<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5615 target-specific value indicating the return address of the current function
5616 or one of its callers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5617
5618<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5619<p>The argument to this intrinsic indicates which function to return the address
5620 for. Zero indicates the calling function, one indicates its caller, etc.
5621 The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5622
5623<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5624<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5625 indicating the return address of the specified call frame, or zero if it
5626 cannot be identified. The value returned by this intrinsic is likely to be
5627 incorrect or 0 for arguments other than zero, so it should only be used for
5628 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5629
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5630<p>Note that calling this intrinsic does not prevent function inlining or other
5631 aggressive transformations, so the value returned may not be that of the
5632 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5633
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5634</div>
5635
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5636<!-- _______________________________________________________________________ -->
5637<div class="doc_subsubsection">
5638 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
5639</div>
5640
5641<div class="doc_text">
5642
5643<h5>Syntax:</h5>
5644<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5645 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5646</pre>
5647
5648<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5649<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5650 target-specific frame pointer value for the specified stack frame.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5651
5652<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5653<p>The argument to this intrinsic indicates which function to return the frame
5654 pointer for. Zero indicates the calling function, one indicates its caller,
5655 etc. The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5656
5657<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5658<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5659 indicating the frame address of the specified call frame, or zero if it
5660 cannot be identified. The value returned by this intrinsic is likely to be
5661 incorrect or 0 for arguments other than zero, so it should only be used for
5662 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5663
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5664<p>Note that calling this intrinsic does not prevent function inlining or other
5665 aggressive transformations, so the value returned may not be that of the
5666 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5667
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5668</div>
5669
5670<!-- _______________________________________________________________________ -->
5671<div class="doc_subsubsection">
5672 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
5673</div>
5674
5675<div class="doc_text">
5676
5677<h5>Syntax:</h5>
5678<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5679 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5680</pre>
5681
5682<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5683<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5684 of the function stack, for use
5685 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5686 useful for implementing language features like scoped automatic variable
5687 sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5688
5689<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5690<p>This intrinsic returns a opaque pointer value that can be passed
5691 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5692 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5693 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5694 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5695 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5696 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5697
5698</div>
5699
5700<!-- _______________________________________________________________________ -->
5701<div class="doc_subsubsection">
5702 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
5703</div>
5704
5705<div class="doc_text">
5706
5707<h5>Syntax:</h5>
5708<pre>
5709 declare void @llvm.stackrestore(i8 * %ptr)
5710</pre>
5711
5712<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5713<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5714 the function stack to the state it was in when the
5715 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5716 executed. This is useful for implementing language features like scoped
5717 automatic variable sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5718
5719<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5720<p>See the description
5721 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5722
5723</div>
5724
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5725<!-- _______________________________________________________________________ -->
5726<div class="doc_subsubsection">
5727 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
5728</div>
5729
5730<div class="doc_text">
5731
5732<h5>Syntax:</h5>
5733<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5734 declare void @llvm.prefetch(i8* &lt;address&gt;, i32 &lt;rw&gt;, i32 &lt;locality&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5735</pre>
5736
5737<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5738<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5739 insert a prefetch instruction if supported; otherwise, it is a noop.
5740 Prefetches have no effect on the behavior of the program but can change its
5741 performance characteristics.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5742
5743<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5744<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5745 specifier determining if the fetch should be for a read (0) or write (1),
5746 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5747 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5748 and <tt>locality</tt> arguments must be constant integers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5749
5750<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5751<p>This intrinsic does not modify the behavior of the program. In particular,
5752 prefetches cannot trap and do not produce a value. On targets that support
5753 this intrinsic, the prefetch can provide hints to the processor cache for
5754 better performance.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5755
5756</div>
5757
5758<!-- _______________________________________________________________________ -->
5759<div class="doc_subsubsection">
5760 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
5761</div>
5762
5763<div class="doc_text">
5764
5765<h5>Syntax:</h5>
5766<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5767 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5768</pre>
5769
5770<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5771<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5772 Counter (PC) in a region of code to simulators and other tools. The method
5773 is target specific, but it is expected that the marker will use exported
5774 symbols to transmit the PC of the marker. The marker makes no guarantees
5775 that it will remain with any specific instruction after optimizations. It is
5776 possible that the presence of a marker will inhibit optimizations. The
5777 intended use is to be inserted after optimizations to allow correlations of
5778 simulation runs.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5779
5780<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5781<p><tt>id</tt> is a numerical id identifying the marker.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5782
5783<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5784<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]5785 not support this intrinsic may ignore it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5786
5787</div>
5788
5789<!-- _______________________________________________________________________ -->
5790<div class="doc_subsubsection">
5791 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5792</div>
5793
5794<div class="doc_text">
5795
5796<h5>Syntax:</h5>
5797<pre>
5798 declare i64 @llvm.readcyclecounter( )
5799</pre>
5800
5801<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5802<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5803 counter register (or similar low latency, high accuracy clocks) on those
5804 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5805 should map to RPCC. As the backing counters overflow quickly (on the order
5806 of 9 seconds on alpha), this should only be used for small timings.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5807
5808<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5809<p>When directly supported, reading the cycle counter should not modify any
5810 memory. Implementations are allowed to either return a application specific
5811 value or a system wide value. On backends without support, this is lowered
5812 to a constant 0.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5813
5814</div>
5815
5816<!-- ======================================================================= -->
5817<div class="doc_subsection">
5818 <a name="int_libc">Standard C Library Intrinsics</a>
5819</div>
5820
5821<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5822
5823<p>LLVM provides intrinsics for a few important standard C library functions.
5824 These intrinsics allow source-language front-ends to pass information about
5825 the alignment of the pointer arguments to the code generator, providing
5826 opportunity for more efficient code generation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5827
5828</div>
5829
5830<!-- _______________________________________________________________________ -->
5831<div class="doc_subsubsection">
5832 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
5833</div>
5834
5835<div class="doc_text">
5836
5837<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5838<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
5839 integer bit width. Not all targets support all bit widths however.</p>
5840
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5841<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5842 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5843 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5844 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5845 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5846 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5847 i32 &lt;len&gt;, i32 &lt;align&gt;)
5848 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5849 i64 &lt;len&gt;, i32 &lt;align&gt;)
5850</pre>
5851
5852<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5853<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5854 source location to the destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5855
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5856<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5857 intrinsics do not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5858
5859<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5860<p>The first argument is a pointer to the destination, the second is a pointer
5861 to the source. The third argument is an integer argument specifying the
5862 number of bytes to copy, and the fourth argument is the alignment of the
5863 source and destination locations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5864
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]5865<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5866 then the caller guarantees that both the source and destination pointers are
5867 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5868
5869<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5870<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5871 source location to the destination location, which are not allowed to
5872 overlap. It copies "len" bytes of memory over. If the argument is known to
5873 be aligned to some boundary, this can be specified as the fourth argument,
5874 otherwise it should be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5875
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5876</div>
5877
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5878<!-- _______________________________________________________________________ -->
5879<div class="doc_subsubsection">
5880 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
5881</div>
5882
5883<div class="doc_text">
5884
5885<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5886<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5887 width. Not all targets support all bit widths however.</p>
5888
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5889<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5890 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5891 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5892 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5893 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5894 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5895 i32 &lt;len&gt;, i32 &lt;align&gt;)
5896 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5897 i64 &lt;len&gt;, i32 &lt;align&gt;)
5898</pre>
5899
5900<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5901<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
5902 source location to the destination location. It is similar to the
5903 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
5904 overlap.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5905
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5906<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5907 intrinsics do not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5908
5909<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5910<p>The first argument is a pointer to the destination, the second is a pointer
5911 to the source. The third argument is an integer argument specifying the
5912 number of bytes to copy, and the fourth argument is the alignment of the
5913 source and destination locations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5914
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]5915<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5916 then the caller guarantees that the source and destination pointers are
5917 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5918
5919<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5920<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
5921 source location to the destination location, which may overlap. It copies
5922 "len" bytes of memory over. If the argument is known to be aligned to some
5923 boundary, this can be specified as the fourth argument, otherwise it should
5924 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5925
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5926</div>
5927
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5928<!-- _______________________________________________________________________ -->
5929<div class="doc_subsubsection">
5930 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
5931</div>
5932
5933<div class="doc_text">
5934
5935<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5936<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5937 width. Not all targets support all bit widths however.</p>
5938
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5939<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5940 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5941 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5942 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5943 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5944 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5945 i32 &lt;len&gt;, i32 &lt;align&gt;)
5946 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5947 i64 &lt;len&gt;, i32 &lt;align&gt;)
5948</pre>
5949
5950<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5951<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
5952 particular byte value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5953
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5954<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
5955 intrinsic does not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5956
5957<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5958<p>The first argument is a pointer to the destination to fill, the second is the
5959 byte value to fill it with, the third argument is an integer argument
5960 specifying the number of bytes to fill, and the fourth argument is the known
5961 alignment of destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5962
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]5963<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5964 then the caller guarantees that the destination pointer is aligned to that
5965 boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5966
5967<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5968<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
5969 at the destination location. If the argument is known to be aligned to some
5970 boundary, this can be specified as the fourth argument, otherwise it should
5971 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5972
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5973</div>
5974
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5975<!-- _______________________________________________________________________ -->
5976<div class="doc_subsubsection">
5977 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
5978</div>
5979
5980<div class="doc_text">
5981
5982<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5983<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
5984 floating point or vector of floating point type. Not all targets support all
5985 types however.</p>
5986
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5987<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5988 declare float @llvm.sqrt.f32(float %Val)
5989 declare double @llvm.sqrt.f64(double %Val)
5990 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5991 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5992 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5993</pre>
5994
5995<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5996<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
5997 returning the same value as the libm '<tt>sqrt</tt>' functions would.
5998 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
5999 behavior for negative numbers other than -0.0 (which allows for better
6000 optimization, because there is no need to worry about errno being
6001 set). <tt>llvm.sqrt(-0.0)</tt> is defined to return -0.0 like IEEE sqrt.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6002
6003<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6004<p>The argument and return value are floating point numbers of the same
6005 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6006
6007<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6008<p>This function returns the sqrt of the specified operand if it is a
6009 nonnegative floating point number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6010
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6011</div>
6012
6013<!-- _______________________________________________________________________ -->
6014<div class="doc_subsubsection">
6015 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
6016</div>
6017
6018<div class="doc_text">
6019
6020<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6021<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6022 floating point or vector of floating point type. Not all targets support all
6023 types however.</p>
6024
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6025<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]6026 declare float @llvm.powi.f32(float %Val, i32 %power)
6027 declare double @llvm.powi.f64(double %Val, i32 %power)
6028 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6029 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6030 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6031</pre>
6032
6033<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6034<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6035 specified (positive or negative) power. The order of evaluation of
6036 multiplications is not defined. When a vector of floating point type is
6037 used, the second argument remains a scalar integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6038
6039<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6040<p>The second argument is an integer power, and the first is a value to raise to
6041 that power.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6042
6043<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6044<p>This function returns the first value raised to the second power with an
6045 unspecified sequence of rounding operations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6046
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6047</div>
6048
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6049<!-- _______________________________________________________________________ -->
6050<div class="doc_subsubsection">
6051 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6052</div>
6053
6054<div class="doc_text">
6055
6056<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6057<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6058 floating point or vector of floating point type. Not all targets support all
6059 types however.</p>
6060
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6061<pre>
6062 declare float @llvm.sin.f32(float %Val)
6063 declare double @llvm.sin.f64(double %Val)
6064 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6065 declare fp128 @llvm.sin.f128(fp128 %Val)
6066 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6067</pre>
6068
6069<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6070<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6071
6072<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6073<p>The argument and return value are floating point numbers of the same
6074 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6075
6076<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6077<p>This function returns the sine of the specified operand, returning the same
6078 values as the libm <tt>sin</tt> functions would, and handles error conditions
6079 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6080
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6081</div>
6082
6083<!-- _______________________________________________________________________ -->
6084<div class="doc_subsubsection">
6085 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6086</div>
6087
6088<div class="doc_text">
6089
6090<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6091<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6092 floating point or vector of floating point type. Not all targets support all
6093 types however.</p>
6094
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6095<pre>
6096 declare float @llvm.cos.f32(float %Val)
6097 declare double @llvm.cos.f64(double %Val)
6098 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6099 declare fp128 @llvm.cos.f128(fp128 %Val)
6100 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6101</pre>
6102
6103<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6104<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6105
6106<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6107<p>The argument and return value are floating point numbers of the same
6108 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6109
6110<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6111<p>This function returns the cosine of the specified operand, returning the same
6112 values as the libm <tt>cos</tt> functions would, and handles error conditions
6113 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6114
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6115</div>
6116
6117<!-- _______________________________________________________________________ -->
6118<div class="doc_subsubsection">
6119 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6120</div>
6121
6122<div class="doc_text">
6123
6124<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6125<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6126 floating point or vector of floating point type. Not all targets support all
6127 types however.</p>
6128
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6129<pre>
6130 declare float @llvm.pow.f32(float %Val, float %Power)
6131 declare double @llvm.pow.f64(double %Val, double %Power)
6132 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6133 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6134 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6135</pre>
6136
6137<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6138<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6139 specified (positive or negative) power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6140
6141<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6142<p>The second argument is a floating point power, and the first is a value to
6143 raise to that power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6144
6145<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6146<p>This function returns the first value raised to the second power, returning
6147 the same values as the libm <tt>pow</tt> functions would, and handles error
6148 conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6149
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6150</div>
6151
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6152<!-- ======================================================================= -->
6153<div class="doc_subsection">
6154 <a name="int_manip">Bit Manipulation Intrinsics</a>
6155</div>
6156
6157<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6158
6159<p>LLVM provides intrinsics for a few important bit manipulation operations.
6160 These allow efficient code generation for some algorithms.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6161
6162</div>
6163
6164<!-- _______________________________________________________________________ -->
6165<div class="doc_subsubsection">
6166 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
6167</div>
6168
6169<div class="doc_text">
6170
6171<h5>Syntax:</h5>
6172<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6173 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6174
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6175<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6176 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6177 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6178 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6179</pre>
6180
6181<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6182<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6183 values with an even number of bytes (positive multiple of 16 bits). These
6184 are useful for performing operations on data that is not in the target's
6185 native byte order.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6186
6187<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6188<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6189 and low byte of the input i16 swapped. Similarly,
6190 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6191 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6192 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6193 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6194 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6195 more, respectively).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6196
6197</div>
6198
6199<!-- _______________________________________________________________________ -->
6200<div class="doc_subsubsection">
6201 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
6202</div>
6203
6204<div class="doc_text">
6205
6206<h5>Syntax:</h5>
6207<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6208 width. Not all targets support all bit widths however.</p>
6209
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6210<pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6211 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6212 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6213 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6214 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6215 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6216</pre>
6217
6218<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6219<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6220 in a value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6221
6222<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6223<p>The only argument is the value to be counted. The argument may be of any
6224 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6225
6226<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6227<p>The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6228
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6229</div>
6230
6231<!-- _______________________________________________________________________ -->
6232<div class="doc_subsubsection">
6233 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
6234</div>
6235
6236<div class="doc_text">
6237
6238<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6239<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6240 integer bit width. Not all targets support all bit widths however.</p>
6241
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6242<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6243 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6244 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6245 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6246 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6247 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6248</pre>
6249
6250<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6251<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6252 leading zeros in a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6253
6254<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6255<p>The only argument is the value to be counted. The argument may be of any
6256 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6257
6258<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6259<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6260 zeros in a variable. If the src == 0 then the result is the size in bits of
6261 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6262
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6263</div>
6264
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6265<!-- _______________________________________________________________________ -->
6266<div class="doc_subsubsection">
6267 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
6268</div>
6269
6270<div class="doc_text">
6271
6272<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6273<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6274 integer bit width. Not all targets support all bit widths however.</p>
6275
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6276<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6277 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6278 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6279 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6280 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6281 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6282</pre>
6283
6284<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6285<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6286 trailing zeros.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6287
6288<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6289<p>The only argument is the value to be counted. The argument may be of any
6290 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6291
6292<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6293<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6294 zeros in a variable. If the src == 0 then the result is the size in bits of
6295 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6296
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6297</div>
6298
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6299<!-- ======================================================================= -->
6300<div class="doc_subsection">
6301 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6302</div>
6303
6304<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6305
6306<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6307
6308</div>
6309
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6310<!-- _______________________________________________________________________ -->
6311<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6312 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6313</div>
6314
6315<div class="doc_text">
6316
6317<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6318<p>This is an overloaded intrinsic. You can use <tt>llvm.sadd.with.overflow</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6319 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6320
6321<pre>
6322 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6323 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6324 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6325</pre>
6326
6327<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6328<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6329 a signed addition of the two arguments, and indicate whether an overflow
6330 occurred during the signed summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6331
6332<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6333<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6334 be of integer types of any bit width, but they must have the same bit
6335 width. The second element of the result structure must be of
6336 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6337 undergo signed addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6338
6339<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6340<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6341 a signed addition of the two variables. They return a structure &mdash; the
6342 first element of which is the signed summation, and the second element of
6343 which is a bit specifying if the signed summation resulted in an
6344 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6345
6346<h5>Examples:</h5>
6347<pre>
6348 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6349 %sum = extractvalue {i32, i1} %res, 0
6350 %obit = extractvalue {i32, i1} %res, 1
6351 br i1 %obit, label %overflow, label %normal
6352</pre>
6353
6354</div>
6355
6356<!-- _______________________________________________________________________ -->
6357<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6358 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6359</div>
6360
6361<div class="doc_text">
6362
6363<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6364<p>This is an overloaded intrinsic. You can use <tt>llvm.uadd.with.overflow</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6365 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6366
6367<pre>
6368 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6369 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6370 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6371</pre>
6372
6373<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6374<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6375 an unsigned addition of the two arguments, and indicate whether a carry
6376 occurred during the unsigned summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6377
6378<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6379<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6380 be of integer types of any bit width, but they must have the same bit
6381 width. The second element of the result structure must be of
6382 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6383 undergo unsigned addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6384
6385<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6386<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6387 an unsigned addition of the two arguments. They return a structure &mdash;
6388 the first element of which is the sum, and the second element of which is a
6389 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6390
6391<h5>Examples:</h5>
6392<pre>
6393 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6394 %sum = extractvalue {i32, i1} %res, 0
6395 %obit = extractvalue {i32, i1} %res, 1
6396 br i1 %obit, label %carry, label %normal
6397</pre>
6398
6399</div>
6400
6401<!-- _______________________________________________________________________ -->
6402<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6403 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6404</div>
6405
6406<div class="doc_text">
6407
6408<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6409<p>This is an overloaded intrinsic. You can use <tt>llvm.ssub.with.overflow</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6410 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6411
6412<pre>
6413 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6414 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6415 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6416</pre>
6417
6418<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6419<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6420 a signed subtraction of the two arguments, and indicate whether an overflow
6421 occurred during the signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6422
6423<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6424<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6425 be of integer types of any bit width, but they must have the same bit
6426 width. The second element of the result structure must be of
6427 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6428 undergo signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6429
6430<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6431<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6432 a signed subtraction of the two arguments. They return a structure &mdash;
6433 the first element of which is the subtraction, and the second element of
6434 which is a bit specifying if the signed subtraction resulted in an
6435 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6436
6437<h5>Examples:</h5>
6438<pre>
6439 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6440 %sum = extractvalue {i32, i1} %res, 0
6441 %obit = extractvalue {i32, i1} %res, 1
6442 br i1 %obit, label %overflow, label %normal
6443</pre>
6444
6445</div>
6446
6447<!-- _______________________________________________________________________ -->
6448<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6449 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6450</div>
6451
6452<div class="doc_text">
6453
6454<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6455<p>This is an overloaded intrinsic. You can use <tt>llvm.usub.with.overflow</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6456 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6457
6458<pre>
6459 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6460 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6461 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6462</pre>
6463
6464<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6465<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6466 an unsigned subtraction of the two arguments, and indicate whether an
6467 overflow occurred during the unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6468
6469<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6470<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6471 be of integer types of any bit width, but they must have the same bit
6472 width. The second element of the result structure must be of
6473 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6474 undergo unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6475
6476<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6477<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6478 an unsigned subtraction of the two arguments. They return a structure &mdash;
6479 the first element of which is the subtraction, and the second element of
6480 which is a bit specifying if the unsigned subtraction resulted in an
6481 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6482
6483<h5>Examples:</h5>
6484<pre>
6485 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6486 %sum = extractvalue {i32, i1} %res, 0
6487 %obit = extractvalue {i32, i1} %res, 1
6488 br i1 %obit, label %overflow, label %normal
6489</pre>
6490
6491</div>
6492
6493<!-- _______________________________________________________________________ -->
6494<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6495 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6496</div>
6497
6498<div class="doc_text">
6499
6500<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6501<p>This is an overloaded intrinsic. You can use <tt>llvm.smul.with.overflow</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6502 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6503
6504<pre>
6505 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6506 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6507 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6508</pre>
6509
6510<h5>Overview:</h5>
6511
6512<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6513 a signed multiplication of the two arguments, and indicate whether an
6514 overflow occurred during the signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6515
6516<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6517<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6518 be of integer types of any bit width, but they must have the same bit
6519 width. The second element of the result structure must be of
6520 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6521 undergo signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6522
6523<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6524<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6525 a signed multiplication of the two arguments. They return a structure &mdash;
6526 the first element of which is the multiplication, and the second element of
6527 which is a bit specifying if the signed multiplication resulted in an
6528 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6529
6530<h5>Examples:</h5>
6531<pre>
6532 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6533 %sum = extractvalue {i32, i1} %res, 0
6534 %obit = extractvalue {i32, i1} %res, 1
6535 br i1 %obit, label %overflow, label %normal
6536</pre>
6537
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6538</div>
6539
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6540<!-- _______________________________________________________________________ -->
6541<div class="doc_subsubsection">
6542 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6543</div>
6544
6545<div class="doc_text">
6546
6547<h5>Syntax:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6548<p>This is an overloaded intrinsic. You can use <tt>llvm.umul.with.overflow</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6549 on any integer bit width.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6550
6551<pre>
6552 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6553 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6554 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6555</pre>
6556
6557<h5>Overview:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6558<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6559 a unsigned multiplication of the two arguments, and indicate whether an
6560 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6561
6562<h5>Arguments:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6563<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6564 be of integer types of any bit width, but they must have the same bit
6565 width. The second element of the result structure must be of
6566 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6567 undergo unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6568
6569<h5>Semantics:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6570<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6571 an unsigned multiplication of the two arguments. They return a structure
6572 &mdash; the first element of which is the multiplication, and the second
6573 element of which is a bit specifying if the unsigned multiplication resulted
6574 in an overflow.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6575
6576<h5>Examples:</h5>
6577<pre>
6578 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6579 %sum = extractvalue {i32, i1} %res, 0
6580 %obit = extractvalue {i32, i1} %res, 1
6581 br i1 %obit, label %overflow, label %normal
6582</pre>
6583
6584</div>
6585
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6586<!-- ======================================================================= -->
6587<div class="doc_subsection">
6588 <a name="int_debugger">Debugger Intrinsics</a>
6589</div>
6590
6591<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6592
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6593<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6594 prefix), are described in
6595 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6596 Level Debugging</a> document.</p>
6597
6598</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6599
6600<!-- ======================================================================= -->
6601<div class="doc_subsection">
6602 <a name="int_eh">Exception Handling Intrinsics</a>
6603</div>
6604
6605<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6606
6607<p>The LLVM exception handling intrinsics (which all start with
6608 <tt>llvm.eh.</tt> prefix), are described in
6609 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6610 Handling</a> document.</p>
6611
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6612</div>
6613
6614<!-- ======================================================================= -->
6615<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6616 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6617</div>
6618
6619<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6620
6621<p>This intrinsic makes it possible to excise one parameter, marked with
6622 the <tt>nest</tt> attribute, from a function. The result is a callable
6623 function pointer lacking the nest parameter - the caller does not need to
6624 provide a value for it. Instead, the value to use is stored in advance in a
6625 "trampoline", a block of memory usually allocated on the stack, which also
6626 contains code to splice the nest value into the argument list. This is used
6627 to implement the GCC nested function address extension.</p>
6628
6629<p>For example, if the function is
6630 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6631 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6632 follows:</p>
6633
6634<div class="doc_code">
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6635<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6636 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6637 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6638 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6639 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6640</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6641</div>
6642
6643<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6644 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6645
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6646</div>
6647
6648<!-- _______________________________________________________________________ -->
6649<div class="doc_subsubsection">
6650 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6651</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6652
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6653<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6654
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6655<h5>Syntax:</h5>
6656<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6657 declare i8* @llvm.init.trampoline(i8* &lt;tramp&gt;, i8* &lt;func&gt;, i8* &lt;nval&gt;)
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6658</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6659
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6660<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6661<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6662 function pointer suitable for executing it.</p>
6663
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6664<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6665<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6666 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6667 sufficiently aligned block of memory; this memory is written to by the
6668 intrinsic. Note that the size and the alignment are target-specific - LLVM
6669 currently provides no portable way of determining them, so a front-end that
6670 generates this intrinsic needs to have some target-specific knowledge.
6671 The <tt>func</tt> argument must hold a function bitcast to
6672 an <tt>i8*</tt>.</p>
6673
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6674<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6675<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6676 dependent code, turning it into a function. A pointer to this function is
6677 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6678 function pointer type</a> before being called. The new function's signature
6679 is the same as that of <tt>func</tt> with any arguments marked with
6680 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6681 is allowed, and it must be of pointer type. Calling the new function is
6682 equivalent to calling <tt>func</tt> with the same argument list, but
6683 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6684 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6685 by <tt>tramp</tt> is modified, then the effect of any later call to the
6686 returned function pointer is undefined.</p>
6687
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6688</div>
6689
6690<!-- ======================================================================= -->
6691<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6692 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6693</div>
6694
6695<div class="doc_text">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6696
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6697<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6698 hardware constructs for atomic operations and memory synchronization. This
6699 provides an interface to the hardware, not an interface to the programmer. It
6700 is aimed at a low enough level to allow any programming models or APIs
6701 (Application Programming Interfaces) which need atomic behaviors to map
6702 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6703 hardware provides a "universal IR" for source languages, it also provides a
6704 starting point for developing a "universal" atomic operation and
6705 synchronization IR.</p>
6706
6707<p>These do <em>not</em> form an API such as high-level threading libraries,
6708 software transaction memory systems, atomic primitives, and intrinsic
6709 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6710 application libraries. The hardware interface provided by LLVM should allow
6711 a clean implementation of all of these APIs and parallel programming models.
6712 No one model or paradigm should be selected above others unless the hardware
6713 itself ubiquitously does so.</p>
6714
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6715</div>
6716
6717<!-- _______________________________________________________________________ -->
6718<div class="doc_subsubsection">
6719 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6720</div>
6721<div class="doc_text">
6722<h5>Syntax:</h5>
6723<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6724 declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;, i1 &lt;device&gt; )
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6725</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6726
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6727<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6728<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6729 specific pairs of memory access types.</p>
6730
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6731<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6732<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6733 The first four arguments enables a specific barrier as listed below. The
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]6734 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6735 memory.</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6736
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6737<ul>
6738 <li><tt>ll</tt>: load-load barrier</li>
6739 <li><tt>ls</tt>: load-store barrier</li>
6740 <li><tt>sl</tt>: store-load barrier</li>
6741 <li><tt>ss</tt>: store-store barrier</li>
6742 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6743</ul>
6744
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6745<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6746<p>This intrinsic causes the system to enforce some ordering constraints upon
6747 the loads and stores of the program. This barrier does not
6748 indicate <em>when</em> any events will occur, it only enforces
6749 an <em>order</em> in which they occur. For any of the specified pairs of load
6750 and store operations (f.ex. load-load, or store-load), all of the first
6751 operations preceding the barrier will complete before any of the second
6752 operations succeeding the barrier begin. Specifically the semantics for each
6753 pairing is as follows:</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6754
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6755<ul>
6756 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6757 after the barrier begins.</li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]6758 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6759 store after the barrier begins.</li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]6760 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6761 store after the barrier begins.</li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]6762 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6763 load after the barrier begins.</li>
6764</ul>
6765
6766<p>These semantics are applied with a logical "and" behavior when more than one
6767 is enabled in a single memory barrier intrinsic.</p>
6768
6769<p>Backends may implement stronger barriers than those requested when they do
6770 not support as fine grained a barrier as requested. Some architectures do
6771 not need all types of barriers and on such architectures, these become
6772 noops.</p>
6773
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6774<h5>Example:</h5>
6775<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6776%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6777%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6778 store i32 4, %ptr
6779
6780%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6781 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6782 <i>; guarantee the above finishes</i>
6783 store i32 8, %ptr <i>; before this begins</i>
6784</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6785
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6786</div>
6787
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6788<!-- _______________________________________________________________________ -->
6789<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6790 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6791</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6792
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6793<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6794
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6795<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6796<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6797 any integer bit width and for different address spaces. Not all targets
6798 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6799
6800<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6801 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6802 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6803 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6804 declare i64 @llvm.atomic.cmp.swap.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;cmp&gt;, i64 &lt;val&gt; )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6805</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6806
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6807<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6808<p>This loads a value in memory and compares it to a given value. If they are
6809 equal, it stores a new value into the memory.</p>
6810
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6811<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6812<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
6813 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6814 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6815 this integer type. While any bit width integer may be used, targets may only
6816 lower representations they support in hardware.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6817
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6818<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6819<p>This entire intrinsic must be executed atomically. It first loads the value
6820 in memory pointed to by <tt>ptr</tt> and compares it with the
6821 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
6822 memory. The loaded value is yielded in all cases. This provides the
6823 equivalent of an atomic compare-and-swap operation within the SSA
6824 framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6825
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6826<h5>Examples:</h5>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6827<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6828%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6829%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6830 store i32 4, %ptr
6831
6832%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6833%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6834 <i>; yields {i32}:result1 = 4</i>
6835%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6836%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6837
6838%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6839%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6840 <i>; yields {i32}:result2 = 8</i>
6841%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6842
6843%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6844</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6845
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6846</div>
6847
6848<!-- _______________________________________________________________________ -->
6849<div class="doc_subsubsection">
6850 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6851</div>
6852<div class="doc_text">
6853<h5>Syntax:</h5>
6854
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6855<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6856 integer bit width. Not all targets support all bit widths however.</p>
6857
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6858<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6859 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6860 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6861 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6862 declare i64 @llvm.atomic.swap.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6863</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6864
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6865<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6866<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6867 the value from memory. It then stores the value in <tt>val</tt> in the memory
6868 at <tt>ptr</tt>.</p>
6869
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6870<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6871<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
6872 the <tt>val</tt> argument and the result must be integers of the same bit
6873 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6874 integer type. The targets may only lower integer representations they
6875 support.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6876
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6877<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6878<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6879 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6880 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6881
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6882<h5>Examples:</h5>
6883<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6884%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6885%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6886 store i32 4, %ptr
6887
6888%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6889%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6890 <i>; yields {i32}:result1 = 4</i>
6891%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6892%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6893
6894%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6895%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6896 <i>; yields {i32}:result2 = 8</i>
6897
6898%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6899%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6900</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6901
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6902</div>
6903
6904<!-- _______________________________________________________________________ -->
6905<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6906 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6907
6908</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6909
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6910<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6911
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6912<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6913<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
6914 any integer bit width. Not all targets support all bit widths however.</p>
6915
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6916<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6917 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6918 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6919 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6920 declare i64 @llvm.atomic.load.add.i64..p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6921</pre>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6922
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6923<h5>Overview:</h5>
6924<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
6925 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6926
6927<h5>Arguments:</h5>
6928<p>The intrinsic takes two arguments, the first a pointer to an integer value
6929 and the second an integer value. The result is also an integer value. These
6930 integer types can have any bit width, but they must all have the same bit
6931 width. The targets may only lower integer representations they support.</p>
6932
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6933<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6934<p>This intrinsic does a series of operations atomically. It first loads the
6935 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6936 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6937
6938<h5>Examples:</h5>
6939<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6940%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6941%ptr = bitcast i8* %mallocP to i32*
6942 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6943%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6944 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6945%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6946 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6947%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6948 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6949%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6950</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6951
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6952</div>
6953
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6954<!-- _______________________________________________________________________ -->
6955<div class="doc_subsubsection">
6956 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6957
6958</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6959
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6960<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6961
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6962<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6963<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
6964 any integer bit width and for different address spaces. Not all targets
6965 support all bit widths however.</p>
6966
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6967<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6968 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6969 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6970 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6971 declare i64 @llvm.atomic.load.sub.i64.p0i32( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6972</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6973
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6974<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]6975<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6976 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6977
6978<h5>Arguments:</h5>
6979<p>The intrinsic takes two arguments, the first a pointer to an integer value
6980 and the second an integer value. The result is also an integer value. These
6981 integer types can have any bit width, but they must all have the same bit
6982 width. The targets may only lower integer representations they support.</p>
6983
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6984<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6985<p>This intrinsic does a series of operations atomically. It first loads the
6986 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6987 result to <tt>ptr</tt>. It yields the original value stored
6988 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6989
6990<h5>Examples:</h5>
6991<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6992%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6993%ptr = bitcast i8* %mallocP to i32*
6994 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6995%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6996 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6997%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6998 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6999%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7000 <i>; yields {i32}:result3 = 2</i>
7001%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
7002</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7003
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7004</div>
7005
7006<!-- _______________________________________________________________________ -->
7007<div class="doc_subsubsection">
7008 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
7009 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
7010 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
7011 <a name="int_atomic_load_xor">'<tt>llvm.atomic.load.xor.*</tt>' Intrinsic</a><br>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7012</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7013
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7014<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7015
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7016<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7017<p>These are overloaded intrinsics. You can
7018 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
7019 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7020 bit width and for different address spaces. Not all targets support all bit
7021 widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7022
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7023<pre>
7024 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7025 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7026 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7027 declare i64 @llvm.atomic.load.and.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7028</pre>
7029
7030<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7031 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7032 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7033 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7034 declare i64 @llvm.atomic.load.or.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7035</pre>
7036
7037<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7038 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7039 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7040 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7041 declare i64 @llvm.atomic.load.nand.i64.p0i32( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7042</pre>
7043
7044<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7045 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7046 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7047 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7048 declare i64 @llvm.atomic.load.xor.i64.p0i32( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7049</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7050
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7051<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7052<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7053 the value stored in memory at <tt>ptr</tt>. It yields the original value
7054 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7055
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7056<h5>Arguments:</h5>
7057<p>These intrinsics take two arguments, the first a pointer to an integer value
7058 and the second an integer value. The result is also an integer value. These
7059 integer types can have any bit width, but they must all have the same bit
7060 width. The targets may only lower integer representations they support.</p>
7061
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7062<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7063<p>These intrinsics does a series of operations atomically. They first load the
7064 value stored at <tt>ptr</tt>. They then do the bitwise
7065 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7066 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7067
7068<h5>Examples:</h5>
7069<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7070%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7071%ptr = bitcast i8* %mallocP to i32*
7072 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7073%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7074 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7075%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7076 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7077%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7078 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7079%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7080 <i>; yields {i32}:result3 = FF</i>
7081%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7082</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7083
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7084</div>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7085
7086<!-- _______________________________________________________________________ -->
7087<div class="doc_subsubsection">
7088 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7089 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7090 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7091 <a name="int_atomic_load_umin">'<tt>llvm.atomic.load.umin.*</tt>' Intrinsic</a><br>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7092</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7093
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7094<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7095
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7096<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7097<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7098 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7099 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7100 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7101
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7102<pre>
7103 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7104 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7105 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7106 declare i64 @llvm.atomic.load.max.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7107</pre>
7108
7109<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7110 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7111 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7112 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7113 declare i64 @llvm.atomic.load.min.i64..p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7114</pre>
7115
7116<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7117 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7118 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7119 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7120 declare i64 @llvm.atomic.load.umax.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7121</pre>
7122
7123<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7124 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7125 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7126 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7127 declare i64 @llvm.atomic.load.umin.i64..p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7128</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7129
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7130<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7131<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7132 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7133 original value at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7134
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7135<h5>Arguments:</h5>
7136<p>These intrinsics take two arguments, the first a pointer to an integer value
7137 and the second an integer value. The result is also an integer value. These
7138 integer types can have any bit width, but they must all have the same bit
7139 width. The targets may only lower integer representations they support.</p>
7140
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7141<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7142<p>These intrinsics does a series of operations atomically. They first load the
7143 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7144 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7145 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7146
7147<h5>Examples:</h5>
7148<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7149%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7150%ptr = bitcast i8* %mallocP to i32*
7151 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7152%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7153 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7154%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7155 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7156%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7157 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7158%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7159 <i>; yields {i32}:result3 = 8</i>
7160%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7161</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7162
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7163</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7164
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7165
7166<!-- ======================================================================= -->
7167<div class="doc_subsection">
7168 <a name="int_memorymarkers">Memory Use Markers</a>
7169</div>
7170
7171<div class="doc_text">
7172
7173<p>This class of intrinsics exists to information about the lifetime of memory
7174 objects and ranges where variables are immutable.</p>
7175
7176</div>
7177
7178<!-- _______________________________________________________________________ -->
7179<div class="doc_subsubsection">
7180 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7181</div>
7182
7183<div class="doc_text">
7184
7185<h5>Syntax:</h5>
7186<pre>
7187 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7188</pre>
7189
7190<h5>Overview:</h5>
7191<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7192 object's lifetime.</p>
7193
7194<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7195<p>The first argument is a constant integer representing the size of the
7196 object, or -1 if it is variable sized. The second argument is a pointer to
7197 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7198
7199<h5>Semantics:</h5>
7200<p>This intrinsic indicates that before this point in the code, the value of the
7201 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
Nick Lewyckyf8a5f302009-10-27 16:56:58 +0000[diff] [blame]7202 never be used and has an undefined value. A load from the pointer that
7203 precedes this intrinsic can be replaced with
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7204 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7205
7206</div>
7207
7208<!-- _______________________________________________________________________ -->
7209<div class="doc_subsubsection">
7210 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7211</div>
7212
7213<div class="doc_text">
7214
7215<h5>Syntax:</h5>
7216<pre>
7217 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7218</pre>
7219
7220<h5>Overview:</h5>
7221<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7222 object's lifetime.</p>
7223
7224<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7225<p>The first argument is a constant integer representing the size of the
7226 object, or -1 if it is variable sized. The second argument is a pointer to
7227 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7228
7229<h5>Semantics:</h5>
7230<p>This intrinsic indicates that after this point in the code, the value of the
7231 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7232 never be used and has an undefined value. Any stores into the memory object
7233 following this intrinsic may be removed as dead.
7234
7235</div>
7236
7237<!-- _______________________________________________________________________ -->
7238<div class="doc_subsubsection">
7239 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7240</div>
7241
7242<div class="doc_text">
7243
7244<h5>Syntax:</h5>
7245<pre>
7246 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7247</pre>
7248
7249<h5>Overview:</h5>
7250<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7251 a memory object will not change.</p>
7252
7253<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7254<p>The first argument is a constant integer representing the size of the
7255 object, or -1 if it is variable sized. The second argument is a pointer to
7256 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7257
7258<h5>Semantics:</h5>
7259<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7260 the return value, the referenced memory location is constant and
7261 unchanging.</p>
7262
7263</div>
7264
7265<!-- _______________________________________________________________________ -->
7266<div class="doc_subsubsection">
7267 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7268</div>
7269
7270<div class="doc_text">
7271
7272<h5>Syntax:</h5>
7273<pre>
7274 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7275</pre>
7276
7277<h5>Overview:</h5>
7278<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7279 a memory object are mutable.</p>
7280
7281<h5>Arguments:</h5>
7282<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7283 The second argument is a constant integer representing the size of the
7284 object, or -1 if it is variable sized and the third argument is a pointer
7285 to the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7286
7287<h5>Semantics:</h5>
7288<p>This intrinsic indicates that the memory is mutable again.</p>
7289
7290</div>
7291
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7292<!-- ======================================================================= -->
7293<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7294 <a name="int_general">General Intrinsics</a>
7295</div>
7296
7297<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7298
7299<p>This class of intrinsics is designed to be generic and has no specific
7300 purpose.</p>
7301
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7302</div>
7303
7304<!-- _______________________________________________________________________ -->
7305<div class="doc_subsubsection">
7306 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7307</div>
7308
7309<div class="doc_text">
7310
7311<h5>Syntax:</h5>
7312<pre>
7313 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7314</pre>
7315
7316<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7317<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7318
7319<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7320<p>The first argument is a pointer to a value, the second is a pointer to a
7321 global string, the third is a pointer to a global string which is the source
7322 file name, and the last argument is the line number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7323
7324<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7325<p>This intrinsic allows annotation of local variables with arbitrary strings.
7326 This can be useful for special purpose optimizations that want to look for
7327 these annotations. These have no other defined use, they are ignored by code
7328 generation and optimization.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7329
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7330</div>
7331
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7332<!-- _______________________________________________________________________ -->
7333<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]7334 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7335</div>
7336
7337<div class="doc_text">
7338
7339<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7340<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7341 any integer bit width.</p>
7342
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7343<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +0000[diff] [blame]7344 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7345 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7346 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7347 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7348 declare i256 @llvm.annotation.i256(i256 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7349</pre>
7350
7351<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7352<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7353
7354<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7355<p>The first argument is an integer value (result of some expression), the
7356 second is a pointer to a global string, the third is a pointer to a global
7357 string which is the source file name, and the last argument is the line
7358 number. It returns the value of the first argument.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7359
7360<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7361<p>This intrinsic allows annotations to be put on arbitrary expressions with
7362 arbitrary strings. This can be useful for special purpose optimizations that
7363 want to look for these annotations. These have no other defined use, they
7364 are ignored by code generation and optimization.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7365
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7366</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7367
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7368<!-- _______________________________________________________________________ -->
7369<div class="doc_subsubsection">
7370 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7371</div>
7372
7373<div class="doc_text">
7374
7375<h5>Syntax:</h5>
7376<pre>
7377 declare void @llvm.trap()
7378</pre>
7379
7380<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7381<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7382
7383<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7384<p>None.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7385
7386<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7387<p>This intrinsics is lowered to the target dependent trap instruction. If the
7388 target does not have a trap instruction, this intrinsic will be lowered to
7389 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7390
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7391</div>
7392
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7393<!-- _______________________________________________________________________ -->
7394<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +0000[diff] [blame]7395 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7396</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7397
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7398<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7399
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7400<h5>Syntax:</h5>
7401<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7402 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7403</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7404
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7405<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7406<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7407 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7408 ensure that it is placed on the stack before local variables.</p>
7409
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7410<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7411<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7412 arguments. The first argument is the value loaded from the stack
7413 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7414 that has enough space to hold the value of the guard.</p>
7415
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7416<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7417<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7418 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7419 stack. This is to ensure that if a local variable on the stack is
7420 overwritten, it will destroy the value of the guard. When the function exits,
7421 the guard on the stack is checked against the original guard. If they're
7422 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7423 function.</p>
7424
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7425</div>
7426
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7427<!-- _______________________________________________________________________ -->
7428<div class="doc_subsubsection">
7429 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7430</div>
7431
7432<div class="doc_text">
7433
7434<h5>Syntax:</h5>
7435<pre>
Eric Christopher0101f9d2009-12-23 00:29:49 +0000[diff] [blame]7436 declare i32 @llvm.objectsize.i32( i8* &lt;object&gt;, i1 &lt;type&gt; )
7437 declare i64 @llvm.objectsize.i64( i8* &lt;object&gt;, i1 &lt;type&gt; )
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7438</pre>
7439
7440<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7441<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information
Eric Christopher184f44d2010-01-08 21:42:39 +0000[diff] [blame]7442 to the optimizers to discover at compile time either a) when an
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7443 operation like memcpy will either overflow a buffer that corresponds to
7444 an object, or b) to determine that a runtime check for overflow isn't
7445 necessary. An object in this context means an allocation of a
Eric Christopher0101f9d2009-12-23 00:29:49 +0000[diff] [blame]7446 specific class, structure, array, or other object.</p>
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7447
7448<h5>Arguments:</h5>
7449<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher0101f9d2009-12-23 00:29:49 +0000[diff] [blame]7450 argument is a pointer to or into the <tt>object</tt>. The second argument
7451 is a boolean 0 or 1. This argument determines whether you want the
7452 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
7453 1, variables are not allowed.</p>
7454
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7455<h5>Semantics:</h5>
7456<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7457 representing the size of the object concerned or <tt>i32/i64 -1 or 0</tt>
7458 (depending on the <tt>type</tt> argument if the size cannot be determined
7459 at compile time.</p>
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7460
7461</div>
7462
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7463<!-- *********************************************************************** -->
7464<hr>
7465<address>
7466 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]7467 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7468 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]7469 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7470
7471 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
7472 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
7473 Last modified: $Date$
7474</address>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]7475
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7476</body>
7477</html>