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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / f72638617ec5cfe1f61950a1fbd6ee066f4454d5 / . / docs / LangRef.html
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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>
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]92 <li><a href="#trapvalues">Trap Values</a></li>
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]93 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]94 <li><a href="#constantexprs">Constant Expressions</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]95 </ol>
96 </li>
97 <li><a href="#othervalues">Other Values</a>
98 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]99 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]100 <li><a href="#metadata">Metadata Nodes and Metadata Strings</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]101 </ol>
102 </li>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]103 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
104 <ol>
105 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]106 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
107 Global Variable</a></li>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]108 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
109 Global Variable</a></li>
110 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
111 Global Variable</a></li>
112 </ol>
113 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]114 <li><a href="#instref">Instruction Reference</a>
115 <ol>
116 <li><a href="#terminators">Terminator Instructions</a>
117 <ol>
118 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
119 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
120 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]121 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]122 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
123 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
124 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
125 </ol>
126 </li>
127 <li><a href="#binaryops">Binary Operations</a>
128 <ol>
129 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]130 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]131 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]132 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]133 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]134 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]135 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
136 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
137 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
138 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
139 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
140 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
141 </ol>
142 </li>
143 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
144 <ol>
145 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
146 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
147 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
148 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
149 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
150 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
151 </ol>
152 </li>
153 <li><a href="#vectorops">Vector Operations</a>
154 <ol>
155 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
156 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
157 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
158 </ol>
159 </li>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]160 <li><a href="#aggregateops">Aggregate Operations</a>
161 <ol>
162 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
163 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
164 </ol>
165 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]166 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
167 <ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]168 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
169 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
170 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
171 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
172 </ol>
173 </li>
174 <li><a href="#convertops">Conversion Operations</a>
175 <ol>
176 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
177 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
178 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
179 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
180 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
181 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
182 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
183 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
184 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
185 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
186 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
187 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
188 </ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]189 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]190 <li><a href="#otherops">Other Operations</a>
191 <ol>
192 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
193 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
194 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
195 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
196 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
197 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
198 </ol>
199 </li>
200 </ol>
201 </li>
202 <li><a href="#intrinsics">Intrinsic Functions</a>
203 <ol>
204 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
205 <ol>
206 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
207 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
208 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
209 </ol>
210 </li>
211 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
212 <ol>
213 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
214 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
215 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
216 </ol>
217 </li>
218 <li><a href="#int_codegen">Code Generator Intrinsics</a>
219 <ol>
220 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
221 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
222 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
223 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
224 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
225 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
226 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
227 </ol>
228 </li>
229 <li><a href="#int_libc">Standard C Library Intrinsics</a>
230 <ol>
231 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
232 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
233 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
234 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
235 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]236 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
237 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
238 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]239 </ol>
240 </li>
241 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
242 <ol>
243 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
244 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
245 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
246 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]247 </ol>
248 </li>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]249 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
250 <ol>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]251 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
252 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
253 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
254 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
255 <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]256 <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]257 </ol>
258 </li>
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]259 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
260 <ol>
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]261 <li><a href="#int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
262 <li><a href="#int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a></li>
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]263 </ol>
264 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]265 <li><a href="#int_debugger">Debugger intrinsics</a></li>
266 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]267 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]268 <ol>
269 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]270 </ol>
271 </li>
Bill Wendling9127adb2008-11-18 22:10:53 +0000[diff] [blame]272 <li><a href="#int_atomics">Atomic intrinsics</a>
273 <ol>
274 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
275 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
276 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
277 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
278 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
279 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
280 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
281 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
282 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
283 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
284 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
285 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
286 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
287 </ol>
288 </li>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]289 <li><a href="#int_memorymarkers">Memory Use Markers</a>
290 <ol>
291 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
292 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
293 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
294 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
295 </ol>
296 </li>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]297 <li><a href="#int_general">General intrinsics</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]298 <ol>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]299 <li><a href="#int_var_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]300 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]301 <li><a href="#int_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]302 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]303 <li><a href="#int_trap">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]304 '<tt>llvm.trap</tt>' Intrinsic</a></li>
305 <li><a href="#int_stackprotector">
306 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]307 <li><a href="#int_objectsize">
308 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]309 </ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]310 </li>
311 </ol>
312 </li>
313</ol>
314
315<div class="doc_author">
316 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
317 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
318</div>
319
320<!-- *********************************************************************** -->
321<div class="doc_section"> <a name="abstract">Abstract </a></div>
322<!-- *********************************************************************** -->
323
324<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]325
326<p>This document is a reference manual for the LLVM assembly language. LLVM is
327 a Static Single Assignment (SSA) based representation that provides type
328 safety, low-level operations, flexibility, and the capability of representing
329 'all' high-level languages cleanly. It is the common code representation
330 used throughout all phases of the LLVM compilation strategy.</p>
331
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]332</div>
333
334<!-- *********************************************************************** -->
335<div class="doc_section"> <a name="introduction">Introduction</a> </div>
336<!-- *********************************************************************** -->
337
338<div class="doc_text">
339
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]340<p>The LLVM code representation is designed to be used in three different forms:
341 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
342 for fast loading by a Just-In-Time compiler), and as a human readable
343 assembly language representation. This allows LLVM to provide a powerful
344 intermediate representation for efficient compiler transformations and
345 analysis, while providing a natural means to debug and visualize the
346 transformations. The three different forms of LLVM are all equivalent. This
347 document describes the human readable representation and notation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]348
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]349<p>The LLVM representation aims to be light-weight and low-level while being
350 expressive, typed, and extensible at the same time. It aims to be a
351 "universal IR" of sorts, by being at a low enough level that high-level ideas
352 may be cleanly mapped to it (similar to how microprocessors are "universal
353 IR's", allowing many source languages to be mapped to them). By providing
354 type information, LLVM can be used as the target of optimizations: for
355 example, through pointer analysis, it can be proven that a C automatic
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]356 variable is never accessed outside of the current function, allowing it to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]357 be promoted to a simple SSA value instead of a memory location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]358
359</div>
360
361<!-- _______________________________________________________________________ -->
362<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
363
364<div class="doc_text">
365
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]366<p>It is important to note that this document describes 'well formed' LLVM
367 assembly language. There is a difference between what the parser accepts and
368 what is considered 'well formed'. For example, the following instruction is
369 syntactically okay, but not well formed:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]370
371<div class="doc_code">
372<pre>
373%x = <a href="#i_add">add</a> i32 1, %x
374</pre>
375</div>
376
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]377<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
378 LLVM infrastructure provides a verification pass that may be used to verify
379 that an LLVM module is well formed. This pass is automatically run by the
380 parser after parsing input assembly and by the optimizer before it outputs
381 bitcode. The violations pointed out by the verifier pass indicate bugs in
382 transformation passes or input to the parser.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]383
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]384</div>
385
Chris Lattnera83fdc02007-10-03 17:34:29 +0000[diff] [blame]386<!-- Describe the typesetting conventions here. -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]387
388<!-- *********************************************************************** -->
389<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
390<!-- *********************************************************************** -->
391
392<div class="doc_text">
393
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]394<p>LLVM identifiers come in two basic types: global and local. Global
395 identifiers (functions, global variables) begin with the <tt>'@'</tt>
396 character. Local identifiers (register names, types) begin with
397 the <tt>'%'</tt> character. Additionally, there are three different formats
398 for identifiers, for different purposes:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]399
400<ol>
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]401 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]402 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
403 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
404 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
405 other characters in their names can be surrounded with quotes. Special
406 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
407 ASCII code for the character in hexadecimal. In this way, any character
408 can be used in a name value, even quotes themselves.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]409
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]410 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]411 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]412
413 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]414 constants</a>, below.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]415</ol>
416
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]417<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]418 don't need to worry about name clashes with reserved words, and the set of
419 reserved words may be expanded in the future without penalty. Additionally,
420 unnamed identifiers allow a compiler to quickly come up with a temporary
421 variable without having to avoid symbol table conflicts.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]422
423<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]424 languages. There are keywords for different opcodes
425 ('<tt><a href="#i_add">add</a></tt>',
426 '<tt><a href="#i_bitcast">bitcast</a></tt>',
427 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
428 ('<tt><a href="#t_void">void</a></tt>',
429 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
430 reserved words cannot conflict with variable names, because none of them
431 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]432
433<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]434 '<tt>%X</tt>' by 8:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]435
436<p>The easy way:</p>
437
438<div class="doc_code">
439<pre>
440%result = <a href="#i_mul">mul</a> i32 %X, 8
441</pre>
442</div>
443
444<p>After strength reduction:</p>
445
446<div class="doc_code">
447<pre>
448%result = <a href="#i_shl">shl</a> i32 %X, i8 3
449</pre>
450</div>
451
452<p>And the hard way:</p>
453
454<div class="doc_code">
455<pre>
Gabor Greifc0ea7672009-10-28 13:05:07 +0000[diff] [blame]456%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
457%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]458%result = <a href="#i_add">add</a> i32 %1, %1
459</pre>
460</div>
461
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]462<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
463 lexical features of LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]464
465<ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]466 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]467 line.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]468
469 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]470 assigned to a named value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]471
472 <li>Unnamed temporaries are numbered sequentially</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]473</ol>
474
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]475<p>It also shows a convention that we follow in this document. When
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]476 demonstrating instructions, we will follow an instruction with a comment that
477 defines the type and name of value produced. Comments are shown in italic
478 text.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]479
480</div>
481
482<!-- *********************************************************************** -->
483<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
484<!-- *********************************************************************** -->
485
486<!-- ======================================================================= -->
487<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
488</div>
489
490<div class="doc_text">
491
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]492<p>LLVM programs are composed of "Module"s, each of which is a translation unit
493 of the input programs. Each module consists of functions, global variables,
494 and symbol table entries. Modules may be combined together with the LLVM
495 linker, which merges function (and global variable) definitions, resolves
496 forward declarations, and merges symbol table entries. Here is an example of
497 the "hello world" module:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]498
499<div class="doc_code">
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]500<pre>
501<i>; Declare the string constant as a global constant.</i>
502<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]503
504<i>; External declaration of the puts function</i>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]505<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]506
507<i>; Definition of main function</i>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]508define i32 @main() { <i>; i32()* </i>
509 <i>; Convert [13 x i8]* to i8 *...</i>
510 %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]511
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]512 <i>; Call puts function to write out the string to stdout.</i>
513 <a href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]514 <a href="#i_ret">ret</a> i32 0<br>}
515
516<i>; Named metadata</i>
517!1 = metadata !{i32 41}
518!foo = !{!1, null}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]519</pre>
520</div>
521
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]522<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]523 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]524 a <a href="#functionstructure">function definition</a> for
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]525 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
526 "<tt>foo"</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]527
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]528<p>In general, a module is made up of a list of global values, where both
529 functions and global variables are global values. Global values are
530 represented by a pointer to a memory location (in this case, a pointer to an
531 array of char, and a pointer to a function), and have one of the
532 following <a href="#linkage">linkage types</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]533
534</div>
535
536<!-- ======================================================================= -->
537<div class="doc_subsection">
538 <a name="linkage">Linkage Types</a>
539</div>
540
541<div class="doc_text">
542
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]543<p>All Global Variables and Functions have one of the following types of
544 linkage:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]545
546<dl>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]547 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]548 <dd>Global values with private linkage are only directly accessible by objects
549 in the current module. In particular, linking code into a module with an
550 private global value may cause the private to be renamed as necessary to
551 avoid collisions. Because the symbol is private to the module, all
552 references can be updated. This doesn't show up in any symbol table in the
553 object file.</dd>
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000[diff] [blame]554
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]555 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]556 <dd>Similar to private, but the symbol is passed through the assembler and
Chris Lattner06c1ecc2009-08-24 04:32:16 +0000[diff] [blame]557 removed by the linker after evaluation. Note that (unlike private
558 symbols) linker_private symbols are subject to coalescing by the linker:
559 weak symbols get merged and redefinitions are rejected. However, unlike
560 normal strong symbols, they are removed by the linker from the final
561 linked image (executable or dynamic library).</dd>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]562
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]563 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]564 <dd>Similar to private, but the value shows as a local symbol
565 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
566 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]567
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]568 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]569 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]570 into the object file corresponding to the LLVM module. They exist to
571 allow inlining and other optimizations to take place given knowledge of
572 the definition of the global, which is known to be somewhere outside the
573 module. Globals with <tt>available_externally</tt> linkage are allowed to
574 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
575 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]576
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]577 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]578 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattnerd16c5512010-01-09 19:15:14 +0000[diff] [blame]579 the same name when linkage occurs. This can be used to implement
580 some forms of inline functions, templates, or other code which must be
581 generated in each translation unit that uses it, but where the body may
582 be overridden with a more definitive definition later. Unreferenced
583 <tt>linkonce</tt> globals are allowed to be discarded. Note that
584 <tt>linkonce</tt> linkage does not actually allow the optimizer to
585 inline the body of this function into callers because it doesn't know if
586 this definition of the function is the definitive definition within the
587 program or whether it will be overridden by a stronger definition.
588 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
589 linkage.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]590
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]591 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]592 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
593 <tt>linkonce</tt> linkage, except that unreferenced globals with
594 <tt>weak</tt> linkage may not be discarded. This is used for globals that
595 are declared "weak" in C source code.</dd>
596
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]597 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]598 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
599 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
600 global scope.
601 Symbols with "<tt>common</tt>" linkage are merged in the same way as
602 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattner83c4a712009-08-05 05:41:44 +0000[diff] [blame]603 <tt>common</tt> symbols may not have an explicit section,
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]604 must have a zero initializer, and may not be marked '<a
Chris Lattner83c4a712009-08-05 05:41:44 +0000[diff] [blame]605 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
606 have common linkage.</dd>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]607
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_appending">appending</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]610 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]611 pointer to array type. When two global variables with appending linkage
612 are linked together, the two global arrays are appended together. This is
613 the LLVM, typesafe, equivalent of having the system linker append together
614 "sections" with identical names when .o files are linked.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]615
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]616 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]617 <dd>The semantics of this linkage follow the ELF object file model: the symbol
618 is weak until linked, if not linked, the symbol becomes null instead of
619 being an undefined reference.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]620
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]621 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
622 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]623 <dd>Some languages allow differing globals to be merged, such as two functions
624 with different semantics. Other languages, such as <tt>C++</tt>, ensure
625 that only equivalent globals are ever merged (the "one definition rule" -
626 "ODR"). Such languages can use the <tt>linkonce_odr</tt>
627 and <tt>weak_odr</tt> linkage types to indicate that the global will only
628 be merged with equivalent globals. These linkage types are otherwise the
629 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]630
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]631 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]632 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]633 visible, meaning that it participates in linkage and can be used to
634 resolve external symbol references.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]635</dl>
636
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]637<p>The next two types of linkage are targeted for Microsoft Windows platform
638 only. They are designed to support importing (exporting) symbols from (to)
639 DLLs (Dynamic Link Libraries).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]640
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]641<dl>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]642 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]643 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]644 or variable via a global pointer to a pointer that is set up by the DLL
645 exporting the symbol. On Microsoft Windows targets, the pointer name is
646 formed by combining <code>__imp_</code> and the function or variable
647 name.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]648
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]649 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]650 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]651 pointer to a pointer in a DLL, so that it can be referenced with the
652 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
653 name is formed by combining <code>__imp_</code> and the function or
654 variable name.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]655</dl>
656
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]657<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
658 another module defined a "<tt>.LC0</tt>" variable and was linked with this
659 one, one of the two would be renamed, preventing a collision. Since
660 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
661 declarations), they are accessible outside of the current module.</p>
662
663<p>It is illegal for a function <i>declaration</i> to have any linkage type
664 other than "externally visible", <tt>dllimport</tt>
665 or <tt>extern_weak</tt>.</p>
666
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]667<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]668 or <tt>weak_odr</tt> linkages.</p>
669
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]670</div>
671
672<!-- ======================================================================= -->
673<div class="doc_subsection">
674 <a name="callingconv">Calling Conventions</a>
675</div>
676
677<div class="doc_text">
678
679<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]680 and <a href="#i_invoke">invokes</a> can all have an optional calling
681 convention specified for the call. The calling convention of any pair of
682 dynamic caller/callee must match, or the behavior of the program is
683 undefined. The following calling conventions are supported by LLVM, and more
684 may be added in the future:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]685
686<dl>
687 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]688 <dd>This calling convention (the default if no other calling convention is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]689 specified) matches the target C calling conventions. This calling
690 convention supports varargs function calls and tolerates some mismatch in
691 the declared prototype and implemented declaration of the function (as
692 does normal C).</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]693
694 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]695 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]696 (e.g. by passing things in registers). This calling convention allows the
697 target to use whatever tricks it wants to produce fast code for the
698 target, without having to conform to an externally specified ABI
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]699 (Application Binary Interface).
700 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattnerac9a9392010-03-11 00:22:57 +0000[diff] [blame]701 when this or the GHC convention is used.</a> This calling convention
702 does not support varargs and requires the prototype of all callees to
703 exactly match the prototype of the function definition.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]704
705 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]706 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]707 as possible under the assumption that the call is not commonly executed.
708 As such, these calls often preserve all registers so that the call does
709 not break any live ranges in the caller side. This calling convention
710 does not support varargs and requires the prototype of all callees to
711 exactly match the prototype of the function definition.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]712
Chris Lattnerac9a9392010-03-11 00:22:57 +0000[diff] [blame]713 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
714 <dd>This calling convention has been implemented specifically for use by the
715 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
716 It passes everything in registers, going to extremes to achieve this by
717 disabling callee save registers. This calling convention should not be
718 used lightly but only for specific situations such as an alternative to
719 the <em>register pinning</em> performance technique often used when
720 implementing functional programming languages.At the moment only X86
721 supports this convention and it has the following limitations:
722 <ul>
723 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
724 floating point types are supported.</li>
725 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
726 6 floating point parameters.</li>
727 </ul>
728 This calling convention supports
729 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
730 requires both the caller and callee are using it.
731 </dd>
732
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]733 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]734 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]735 target-specific calling conventions to be used. Target specific calling
736 conventions start at 64.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]737</dl>
738
739<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]740 support Pascal conventions or any other well-known target-independent
741 convention.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]742
743</div>
744
745<!-- ======================================================================= -->
746<div class="doc_subsection">
747 <a name="visibility">Visibility Styles</a>
748</div>
749
750<div class="doc_text">
751
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]752<p>All Global Variables and Functions have one of the following visibility
753 styles:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]754
755<dl>
756 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]757 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]758 that the declaration is visible to other modules and, in shared libraries,
759 means that the declared entity may be overridden. On Darwin, default
760 visibility means that the declaration is visible to other modules. Default
761 visibility corresponds to "external linkage" in the language.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]762
763 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]764 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]765 object if they are in the same shared object. Usually, hidden visibility
766 indicates that the symbol will not be placed into the dynamic symbol
767 table, so no other module (executable or shared library) can reference it
768 directly.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]769
770 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]771 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]772 the dynamic symbol table, but that references within the defining module
773 will bind to the local symbol. That is, the symbol cannot be overridden by
774 another module.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]775</dl>
776
777</div>
778
779<!-- ======================================================================= -->
780<div class="doc_subsection">
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]781 <a name="namedtypes">Named Types</a>
782</div>
783
784<div class="doc_text">
785
786<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]787 it easier to read the IR and make the IR more condensed (particularly when
788 recursive types are involved). An example of a name specification is:</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]789
790<div class="doc_code">
791<pre>
792%mytype = type { %mytype*, i32 }
793</pre>
794</div>
795
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]796<p>You may give a name to any <a href="#typesystem">type</a> except
797 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
798 is expected with the syntax "%mytype".</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]799
800<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]801 and that you can therefore specify multiple names for the same type. This
802 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
803 uses structural typing, the name is not part of the type. When printing out
804 LLVM IR, the printer will pick <em>one name</em> to render all types of a
805 particular shape. This means that if you have code where two different
806 source types end up having the same LLVM type, that the dumper will sometimes
807 print the "wrong" or unexpected type. This is an important design point and
808 isn't going to change.</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]809
810</div>
811
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]812<!-- ======================================================================= -->
813<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]814 <a name="globalvars">Global Variables</a>
815</div>
816
817<div class="doc_text">
818
819<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]820 instead of run-time. Global variables may optionally be initialized, may
821 have an explicit section to be placed in, and may have an optional explicit
822 alignment specified. A variable may be defined as "thread_local", which
823 means that it will not be shared by threads (each thread will have a
824 separated copy of the variable). A variable may be defined as a global
825 "constant," which indicates that the contents of the variable
826 will <b>never</b> be modified (enabling better optimization, allowing the
827 global data to be placed in the read-only section of an executable, etc).
828 Note that variables that need runtime initialization cannot be marked
829 "constant" as there is a store to the variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]830
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]831<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
832 constant, even if the final definition of the global is not. This capability
833 can be used to enable slightly better optimization of the program, but
834 requires the language definition to guarantee that optimizations based on the
835 'constantness' are valid for the translation units that do not include the
836 definition.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]837
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]838<p>As SSA values, global variables define pointer values that are in scope
839 (i.e. they dominate) all basic blocks in the program. Global variables
840 always define a pointer to their "content" type because they describe a
841 region of memory, and all memory objects in LLVM are accessed through
842 pointers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]843
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]844<p>A global variable may be declared to reside in a target-specific numbered
845 address space. For targets that support them, address spaces may affect how
846 optimizations are performed and/or what target instructions are used to
847 access the variable. The default address space is zero. The address space
848 qualifier must precede any other attributes.</p>
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]849
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]850<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]851 supports it, it will emit globals to the section specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]852
853<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]854 the alignment is set to zero, the alignment of the global is set by the
855 target to whatever it feels convenient. If an explicit alignment is
856 specified, the global is forced to have at least that much alignment. All
857 alignments must be a power of 2.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]858
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]859<p>For example, the following defines a global in a numbered address space with
860 an initializer, section, and alignment:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]861
862<div class="doc_code">
863<pre>
Dan Gohman21ef02c2009-01-11 00:40:00 +0000[diff] [blame]864@G = addrspace(5) constant float 1.0, section "foo", align 4
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]865</pre>
866</div>
867
868</div>
869
870
871<!-- ======================================================================= -->
872<div class="doc_subsection">
873 <a name="functionstructure">Functions</a>
874</div>
875
876<div class="doc_text">
877
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]878<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]879 optional <a href="#linkage">linkage type</a>, an optional
880 <a href="#visibility">visibility style</a>, an optional
881 <a href="#callingconv">calling convention</a>, a return type, an optional
882 <a href="#paramattrs">parameter attribute</a> for the return type, a function
883 name, a (possibly empty) argument list (each with optional
884 <a href="#paramattrs">parameter attributes</a>), optional
885 <a href="#fnattrs">function attributes</a>, an optional section, an optional
886 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
887 curly brace, a list of basic blocks, and a closing curly brace.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]888
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]889<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
890 optional <a href="#linkage">linkage type</a>, an optional
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]891 <a href="#visibility">visibility style</a>, an optional
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]892 <a href="#callingconv">calling convention</a>, a return type, an optional
893 <a href="#paramattrs">parameter attribute</a> for the return type, a function
894 name, a possibly empty list of arguments, an optional alignment, and an
895 optional <a href="#gc">garbage collector name</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]896
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]897<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]898 (Control Flow Graph) for the function. Each basic block may optionally start
899 with a label (giving the basic block a symbol table entry), contains a list
900 of instructions, and ends with a <a href="#terminators">terminator</a>
901 instruction (such as a branch or function return).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]902
903<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]904 executed on entrance to the function, and it is not allowed to have
905 predecessor basic blocks (i.e. there can not be any branches to the entry
906 block of a function). Because the block can have no predecessors, it also
907 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]908
909<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]910 supports it, it will emit functions to the section specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]911
912<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]913 the alignment is set to zero, the alignment of the function is set by the
914 target to whatever it feels convenient. If an explicit alignment is
915 specified, the function is forced to have at least that much alignment. All
916 alignments must be a power of 2.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]917
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]918<h5>Syntax:</h5>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]919<div class="doc_code">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]920<pre>
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]921define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]922 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
923 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
924 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
925 [<a href="#gc">gc</a>] { ... }
926</pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]927</div>
928
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]929</div>
930
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]931<!-- ======================================================================= -->
932<div class="doc_subsection">
933 <a name="aliasstructure">Aliases</a>
934</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]935
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]936<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]937
938<p>Aliases act as "second name" for the aliasee value (which can be either
939 function, global variable, another alias or bitcast of global value). Aliases
940 may have an optional <a href="#linkage">linkage type</a>, and an
941 optional <a href="#visibility">visibility style</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]942
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]943<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]944<div class="doc_code">
945<pre>
Duncan Sandsd7bfabf2008-09-12 20:48:21 +0000[diff] [blame]946@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]947</pre>
948</div>
949
950</div>
951
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]952<!-- ======================================================================= -->
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]953<div class="doc_subsection">
954 <a name="namedmetadatastructure">Named Metadata</a>
955</div>
956
957<div class="doc_text">
958
Chris Lattnerd0d96292010-01-15 21:50:19 +0000[diff] [blame]959<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
960 nodes</a> (but not metadata strings) and null are the only valid operands for
961 a named metadata.</p>
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]962
963<h5>Syntax:</h5>
964<div class="doc_code">
965<pre>
966!1 = metadata !{metadata !"one"}
967!name = !{null, !1}
968</pre>
969</div>
970
971</div>
972
973<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]974<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]975
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]976<div class="doc_text">
977
978<p>The return type and each parameter of a function type may have a set of
979 <i>parameter attributes</i> associated with them. Parameter attributes are
980 used to communicate additional information about the result or parameters of
981 a function. Parameter attributes are considered to be part of the function,
982 not of the function type, so functions with different parameter attributes
983 can have the same function type.</p>
984
985<p>Parameter attributes are simple keywords that follow the type specified. If
986 multiple parameter attributes are needed, they are space separated. For
987 example:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]988
989<div class="doc_code">
990<pre>
Nick Lewycky3022a742009-02-15 23:06:14 +0000[diff] [blame]991declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]992declare i32 @atoi(i8 zeroext)
993declare signext i8 @returns_signed_char()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]994</pre>
995</div>
996
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]997<p>Note that any attributes for the function result (<tt>nounwind</tt>,
998 <tt>readonly</tt>) come immediately after the argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]999
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1000<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]1001
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1002<dl>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1003 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1004 <dd>This indicates to the code generator that the parameter or return value
1005 should be zero-extended to a 32-bit value by the caller (for a parameter)
1006 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]1007
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1008 <dt><tt><b>signext</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1009 <dd>This indicates to the code generator that the parameter or return value
1010 should be sign-extended to a 32-bit value by the caller (for a parameter)
1011 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]1012
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1013 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1014 <dd>This indicates that this parameter or return value should be treated in a
1015 special target-dependent fashion during while emitting code for a function
1016 call or return (usually, by putting it in a register as opposed to memory,
1017 though some targets use it to distinguish between two different kinds of
1018 registers). Use of this attribute is target-specific.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]1019
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1020 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1021 <dd>This indicates that the pointer parameter should really be passed by value
1022 to the function. The attribute implies that a hidden copy of the pointee
1023 is made between the caller and the callee, so the callee is unable to
1024 modify the value in the callee. This attribute is only valid on LLVM
1025 pointer arguments. It is generally used to pass structs and arrays by
1026 value, but is also valid on pointers to scalars. The copy is considered
1027 to belong to the caller not the callee (for example,
1028 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1029 <tt>byval</tt> parameters). This is not a valid attribute for return
1030 values. The byval attribute also supports specifying an alignment with
1031 the align attribute. This has a target-specific effect on the code
1032 generator that usually indicates a desired alignment for the synthesized
1033 stack slot.</dd>
1034
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1035 <dt><tt><b>sret</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1036 <dd>This indicates that the pointer parameter specifies the address of a
1037 structure that is the return value of the function in the source program.
1038 This pointer must be guaranteed by the caller to be valid: loads and
1039 stores to the structure may be assumed by the callee to not to trap. This
1040 may only be applied to the first parameter. This is not a valid attribute
1041 for return values. </dd>
1042
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1043 <dt><tt><b>noalias</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1044 <dd>This indicates that the pointer does not alias any global or any other
1045 parameter. The caller is responsible for ensuring that this is the
1046 case. On a function return value, <tt>noalias</tt> additionally indicates
1047 that the pointer does not alias any other pointers visible to the
1048 caller. For further details, please see the discussion of the NoAlias
1049 response in
1050 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
1051 analysis</a>.</dd>
1052
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1053 <dt><tt><b>nocapture</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1054 <dd>This indicates that the callee does not make any copies of the pointer
1055 that outlive the callee itself. This is not a valid attribute for return
1056 values.</dd>
1057
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1058 <dt><tt><b>nest</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1059 <dd>This indicates that the pointer parameter can be excised using the
1060 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1061 attribute for return values.</dd>
1062</dl>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1063
1064</div>
1065
1066<!-- ======================================================================= -->
1067<div class="doc_subsection">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1068 <a name="gc">Garbage Collector Names</a>
1069</div>
1070
1071<div class="doc_text">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1072
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1073<p>Each function may specify a garbage collector name, which is simply a
1074 string:</p>
1075
1076<div class="doc_code">
1077<pre>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1078define void @f() gc "name" { ... }
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1079</pre>
1080</div>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1081
1082<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1083 collector which will cause the compiler to alter its output in order to
1084 support the named garbage collection algorithm.</p>
1085
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1086</div>
1087
1088<!-- ======================================================================= -->
1089<div class="doc_subsection">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1090 <a name="fnattrs">Function Attributes</a>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1091</div>
1092
1093<div class="doc_text">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1094
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1095<p>Function attributes are set to communicate additional information about a
1096 function. Function attributes are considered to be part of the function, not
1097 of the function type, so functions with different parameter attributes can
1098 have the same function type.</p>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1099
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1100<p>Function attributes are simple keywords that follow the type specified. If
1101 multiple attributes are needed, they are space separated. For example:</p>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1102
1103<div class="doc_code">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1104<pre>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1105define void @f() noinline { ... }
1106define void @f() alwaysinline { ... }
1107define void @f() alwaysinline optsize { ... }
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1108define void @f() optsize { ... }
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1109</pre>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1110</div>
1111
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1112<dl>
Charles Davisfaa8f752010-02-12 00:31:15 +0000[diff] [blame]1113 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1114 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1115 the backend should forcibly align the stack pointer. Specify the
1116 desired alignment, which must be a power of two, in parentheses.
1117
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1118 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1119 <dd>This attribute indicates that the inliner should attempt to inline this
1120 function into callers whenever possible, ignoring any active inlining size
1121 threshold for this caller.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1122
Jakob Stoklund Olesen77180732010-02-06 01:16:28 +0000[diff] [blame]1123 <dt><tt><b>inlinehint</b></tt></dt>
1124 <dd>This attribute indicates that the source code contained a hint that inlining
1125 this function is desirable (such as the "inline" keyword in C/C++). It
1126 is just a hint; it imposes no requirements on the inliner.</dd>
1127
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1128 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1129 <dd>This attribute indicates that the inliner should never inline this
1130 function in any situation. This attribute may not be used together with
1131 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1132
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1133 <dt><tt><b>optsize</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1134 <dd>This attribute suggests that optimization passes and code generator passes
1135 make choices that keep the code size of this function low, and otherwise
1136 do optimizations specifically to reduce code size.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1137
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1138 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1139 <dd>This function attribute indicates that the function never returns
1140 normally. This produces undefined behavior at runtime if the function
1141 ever does dynamically return.</dd>
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1142
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1143 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1144 <dd>This function attribute indicates that the function never returns with an
1145 unwind or exceptional control flow. If the function does unwind, its
1146 runtime behavior is undefined.</dd>
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1147
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1148 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1149 <dd>This attribute indicates that the function computes its result (or decides
1150 to unwind an exception) based strictly on its arguments, without
1151 dereferencing any pointer arguments or otherwise accessing any mutable
1152 state (e.g. memory, control registers, etc) visible to caller functions.
1153 It does not write through any pointer arguments
1154 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1155 changes any state visible to callers. This means that it cannot unwind
1156 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1157 could use the <tt>unwind</tt> instruction.</dd>
Devang Patela2f9f412009-06-12 19:45:19 +0000[diff] [blame]1158
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1159 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1160 <dd>This attribute indicates that the function does not write through any
1161 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1162 arguments) or otherwise modify any state (e.g. memory, control registers,
1163 etc) visible to caller functions. It may dereference pointer arguments
1164 and read state that may be set in the caller. A readonly function always
1165 returns the same value (or unwinds an exception identically) when called
1166 with the same set of arguments and global state. It cannot unwind an
1167 exception by calling the <tt>C++</tt> exception throwing methods, but may
1168 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovedd7d112009-07-17 18:07:26 +0000[diff] [blame]1169
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1170 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1171 <dd>This attribute indicates that the function should emit a stack smashing
1172 protector. It is in the form of a "canary"&mdash;a random value placed on
1173 the stack before the local variables that's checked upon return from the
1174 function to see if it has been overwritten. A heuristic is used to
1175 determine if a function needs stack protectors or not.<br>
1176<br>
1177 If a function that has an <tt>ssp</tt> attribute is inlined into a
1178 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1179 function will have an <tt>ssp</tt> attribute.</dd>
1180
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1181 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1182 <dd>This attribute indicates that the function should <em>always</em> emit a
1183 stack smashing protector. This overrides
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1184 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1185<br>
1186 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1187 function that doesn't have an <tt>sspreq</tt> attribute or which has
1188 an <tt>ssp</tt> attribute, then the resulting function will have
1189 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1190
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1191 <dt><tt><b>noredzone</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1192 <dd>This attribute indicates that the code generator should not use a red
1193 zone, even if the target-specific ABI normally permits it.</dd>
1194
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1195 <dt><tt><b>noimplicitfloat</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1196 <dd>This attributes disables implicit floating point instructions.</dd>
1197
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1198 <dt><tt><b>naked</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1199 <dd>This attribute disables prologue / epilogue emission for the function.
1200 This can have very system-specific consequences.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1201</dl>
1202
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1203</div>
1204
1205<!-- ======================================================================= -->
1206<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1207 <a name="moduleasm">Module-Level Inline Assembly</a>
1208</div>
1209
1210<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1211
1212<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1213 the GCC "file scope inline asm" blocks. These blocks are internally
1214 concatenated by LLVM and treated as a single unit, but may be separated in
1215 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1216
1217<div class="doc_code">
1218<pre>
1219module asm "inline asm code goes here"
1220module asm "more can go here"
1221</pre>
1222</div>
1223
1224<p>The strings can contain any character by escaping non-printable characters.
1225 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]1226 for the number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1227
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1228<p>The inline asm code is simply printed to the machine code .s file when
1229 assembly code is generated.</p>
1230
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1231</div>
1232
1233<!-- ======================================================================= -->
1234<div class="doc_subsection">
1235 <a name="datalayout">Data Layout</a>
1236</div>
1237
1238<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1239
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1240<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1241 data is to be laid out in memory. The syntax for the data layout is
1242 simply:</p>
1243
1244<div class="doc_code">
1245<pre>
1246target datalayout = "<i>layout specification</i>"
1247</pre>
1248</div>
1249
1250<p>The <i>layout specification</i> consists of a list of specifications
1251 separated by the minus sign character ('-'). Each specification starts with
1252 a letter and may include other information after the letter to define some
1253 aspect of the data layout. The specifications accepted are as follows:</p>
1254
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1255<dl>
1256 <dt><tt>E</tt></dt>
1257 <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]1258 bits with the most significance have the lowest address location.</dd>
1259
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1260 <dt><tt>e</tt></dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1261 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1262 the bits with the least significance have the lowest address
1263 location.</dd>
1264
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1265 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1266 <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]1267 <i>preferred</i> alignments. All sizes are in bits. Specifying
1268 the <i>pref</i> alignment is optional. If omitted, the
1269 preceding <tt>:</tt> should be omitted too.</dd>
1270
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1271 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1272 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1273 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1274
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1275 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1276 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1277 <i>size</i>.</dd>
1278
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1279 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1280 <dd>This specifies the alignment for a floating point type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1281 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1282 (double).</dd>
1283
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1284 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1285 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1286 <i>size</i>.</dd>
1287
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1288 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1289 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1290 <i>size</i>.</dd>
Chris Lattnerece41802009-11-07 09:35:34 +0000[diff] [blame]1291
1292 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1293 <dd>This specifies a set of native integer widths for the target CPU
1294 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1295 "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]1296 this set are considered to support most general arithmetic
Chris Lattnerece41802009-11-07 09:35:34 +0000[diff] [blame]1297 operations efficiently.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1298</dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1299
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1300<p>When constructing the data layout for a given target, LLVM starts with a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1301 default set of specifications which are then (possibly) overriden by the
1302 specifications in the <tt>datalayout</tt> keyword. The default specifications
1303 are given in this list:</p>
1304
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1305<ul>
1306 <li><tt>E</tt> - big endian</li>
Dan Gohmane78194f2010-02-23 02:44:03 +0000[diff] [blame]1307 <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]1308 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1309 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1310 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1311 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1312 <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]1313 alignment of 64-bits</li>
1314 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1315 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1316 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1317 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1318 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1319 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1320</ul>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1321
1322<p>When LLVM is determining the alignment for a given type, it uses the
1323 following rules:</p>
1324
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1325<ol>
1326 <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]1327 specification is used.</li>
1328
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1329 <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]1330 smallest integer type that is larger than the bitwidth of the sought type
1331 is used. If none of the specifications are larger than the bitwidth then
1332 the the largest integer type is used. For example, given the default
1333 specifications above, the i7 type will use the alignment of i8 (next
1334 largest) while both i65 and i256 will use the alignment of i64 (largest
1335 specified).</li>
1336
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1337 <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]1338 largest vector type that is smaller than the sought vector type will be
1339 used as a fall back. This happens because &lt;128 x double&gt; can be
1340 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1341</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1342
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1343</div>
1344
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1345<!-- ======================================================================= -->
1346<div class="doc_subsection">
1347 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1348</div>
1349
1350<div class="doc_text">
1351
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1352<p>Any memory access must be done through a pointer value associated
Andreas Bolka23bece42009-07-27 20:37:10 +0000[diff] [blame]1353with an address range of the memory access, otherwise the behavior
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1354is undefined. Pointer values are associated with address ranges
1355according to the following rules:</p>
1356
1357<ul>
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1358 <li>A pointer value formed from a
1359 <tt><a href="#i_getelementptr">getelementptr</a></tt> instruction
1360 is associated with the addresses associated with the first operand
1361 of the <tt>getelementptr</tt>.</li>
1362 <li>An address of a global variable is associated with the address
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1363 range of the variable's storage.</li>
1364 <li>The result value of an allocation instruction is associated with
1365 the address range of the allocated storage.</li>
1366 <li>A null pointer in the default address-space is associated with
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1367 no address.</li>
1368 <li>A pointer value formed by an
1369 <tt><a href="#i_inttoptr">inttoptr</a></tt> is associated with all
1370 address ranges of all pointer values that contribute (directly or
1371 indirectly) to the computation of the pointer's value.</li>
1372 <li>The result value of a
1373 <tt><a href="#i_bitcast">bitcast</a></tt> is associated with all
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1374 addresses associated with the operand of the <tt>bitcast</tt>.</li>
1375 <li>An integer constant other than zero or a pointer value returned
1376 from a function not defined within LLVM may be associated with address
1377 ranges allocated through mechanisms other than those provided by
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1378 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1379 allocated by mechanisms provided by LLVM.</li>
1380 </ul>
1381
1382<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1383<tt><a href="#i_load">load</a></tt> merely indicates the size and
1384alignment of the memory from which to load, as well as the
1385interpretation of the value. The first operand of a
1386<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1387and alignment of the store.</p>
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1388
1389<p>Consequently, type-based alias analysis, aka TBAA, aka
1390<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1391LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1392additional information which specialized optimization passes may use
1393to implement type-based alias analysis.</p>
1394
1395</div>
1396
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1397<!-- *********************************************************************** -->
1398<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1399<!-- *********************************************************************** -->
1400
1401<div class="doc_text">
1402
1403<p>The LLVM type system is one of the most important features of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1404 intermediate representation. Being typed enables a number of optimizations
1405 to be performed on the intermediate representation directly, without having
1406 to do extra analyses on the side before the transformation. A strong type
1407 system makes it easier to read the generated code and enables novel analyses
1408 and transformations that are not feasible to perform on normal three address
1409 code representations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1410
1411</div>
1412
1413<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1414<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1415Classifications</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1416
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1417<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1418
1419<p>The types fall into a few useful classifications:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1420
1421<table border="1" cellspacing="0" cellpadding="4">
1422 <tbody>
1423 <tr><th>Classification</th><th>Types</th></tr>
1424 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1425 <td><a href="#t_integer">integer</a></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1426 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
1427 </tr>
1428 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1429 <td><a href="#t_floating">floating point</a></td>
1430 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1431 </tr>
1432 <tr>
1433 <td><a name="t_firstclass">first class</a></td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1434 <td><a href="#t_integer">integer</a>,
1435 <a href="#t_floating">floating point</a>,
1436 <a href="#t_pointer">pointer</a>,
Dan Gohmanf6237db2008-06-18 18:42:13 +0000[diff] [blame]1437 <a href="#t_vector">vector</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1438 <a href="#t_struct">structure</a>,
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1439 <a href="#t_union">union</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1440 <a href="#t_array">array</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1441 <a href="#t_label">label</a>,
1442 <a href="#t_metadata">metadata</a>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1443 </td>
1444 </tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1445 <tr>
1446 <td><a href="#t_primitive">primitive</a></td>
1447 <td><a href="#t_label">label</a>,
1448 <a href="#t_void">void</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1449 <a href="#t_floating">floating point</a>,
1450 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1451 </tr>
1452 <tr>
1453 <td><a href="#t_derived">derived</a></td>
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1454 <td><a href="#t_array">array</a>,
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1455 <a href="#t_function">function</a>,
1456 <a href="#t_pointer">pointer</a>,
1457 <a href="#t_struct">structure</a>,
1458 <a href="#t_pstruct">packed structure</a>,
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1459 <a href="#t_union">union</a>,
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1460 <a href="#t_vector">vector</a>,
1461 <a href="#t_opaque">opaque</a>.
Dan Gohman032ba852008-10-14 16:32:04 +0000[diff] [blame]1462 </td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1463 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1464 </tbody>
1465</table>
1466
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1467<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1468 important. Values of these types are the only ones which can be produced by
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1469 instructions.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1470
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1471</div>
1472
1473<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1474<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1475
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1476<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1477
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1478<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1479 system.</p>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1480
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1481</div>
1482
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1483<!-- _______________________________________________________________________ -->
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1484<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1485
1486<div class="doc_text">
1487
1488<h5>Overview:</h5>
1489<p>The integer type is a very simple type that simply specifies an arbitrary
1490 bit width for the integer type desired. Any bit width from 1 bit to
1491 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1492
1493<h5>Syntax:</h5>
1494<pre>
1495 iN
1496</pre>
1497
1498<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1499 value.</p>
1500
1501<h5>Examples:</h5>
1502<table class="layout">
1503 <tr class="layout">
1504 <td class="left"><tt>i1</tt></td>
1505 <td class="left">a single-bit integer.</td>
1506 </tr>
1507 <tr class="layout">
1508 <td class="left"><tt>i32</tt></td>
1509 <td class="left">a 32-bit integer.</td>
1510 </tr>
1511 <tr class="layout">
1512 <td class="left"><tt>i1942652</tt></td>
1513 <td class="left">a really big integer of over 1 million bits.</td>
1514 </tr>
1515</table>
1516
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1517</div>
1518
1519<!-- _______________________________________________________________________ -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1520<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1521
1522<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1523
1524<table>
1525 <tbody>
1526 <tr><th>Type</th><th>Description</th></tr>
1527 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1528 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1529 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1530 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1531 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1532 </tbody>
1533</table>
1534
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1535</div>
1536
1537<!-- _______________________________________________________________________ -->
1538<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1539
1540<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1541
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1542<h5>Overview:</h5>
1543<p>The void type does not represent any value and has no size.</p>
1544
1545<h5>Syntax:</h5>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1546<pre>
1547 void
1548</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1549
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1550</div>
1551
1552<!-- _______________________________________________________________________ -->
1553<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1554
1555<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1556
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1557<h5>Overview:</h5>
1558<p>The label type represents code labels.</p>
1559
1560<h5>Syntax:</h5>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1561<pre>
1562 label
1563</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1564
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1565</div>
1566
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1567<!-- _______________________________________________________________________ -->
1568<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1569
1570<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1571
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1572<h5>Overview:</h5>
Nick Lewyckyeb021882009-09-27 23:27:42 +0000[diff] [blame]1573<p>The metadata type represents embedded metadata. No derived types may be
1574 created from metadata except for <a href="#t_function">function</a>
1575 arguments.
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1576
1577<h5>Syntax:</h5>
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1578<pre>
1579 metadata
1580</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1581
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1582</div>
1583
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1584
1585<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1586<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
1587
1588<div class="doc_text">
1589
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1590<p>The real power in LLVM comes from the derived types in the system. This is
1591 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1592 useful types. Each of these types contain one or more element types which
1593 may be a primitive type, or another derived type. For example, it is
1594 possible to have a two dimensional array, using an array as the element type
1595 of another array.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1596
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1597
1598</div>
1599
1600<!-- _______________________________________________________________________ -->
1601<div class="doc_subsubsection"> <a name="t_aggregate">Aggregate Types</a> </div>
1602
1603<div class="doc_text">
1604
1605<p>Aggregate Types are a subset of derived types that can contain multiple
1606 member types. <a href="#t_array">Arrays</a>,
1607 <a href="#t_struct">structs</a>, <a href="#t_vector">vectors</a> and
1608 <a href="#t_union">unions</a> are aggregate types.</p>
1609
1610</div>
1611
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1612</div>
1613
1614<!-- _______________________________________________________________________ -->
1615<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
1616
1617<div class="doc_text">
1618
1619<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1620<p>The array type is a very simple derived type that arranges elements
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1621 sequentially in memory. The array type requires a size (number of elements)
1622 and an underlying data type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1623
1624<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1625<pre>
1626 [&lt;# elements&gt; x &lt;elementtype&gt;]
1627</pre>
1628
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1629<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1630 be any type with a size.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1631
1632<h5>Examples:</h5>
1633<table class="layout">
1634 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1635 <td class="left"><tt>[40 x i32]</tt></td>
1636 <td class="left">Array of 40 32-bit integer values.</td>
1637 </tr>
1638 <tr class="layout">
1639 <td class="left"><tt>[41 x i32]</tt></td>
1640 <td class="left">Array of 41 32-bit integer values.</td>
1641 </tr>
1642 <tr class="layout">
1643 <td class="left"><tt>[4 x i8]</tt></td>
1644 <td class="left">Array of 4 8-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1645 </tr>
1646</table>
1647<p>Here are some examples of multidimensional arrays:</p>
1648<table class="layout">
1649 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1650 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1651 <td class="left">3x4 array of 32-bit integer values.</td>
1652 </tr>
1653 <tr class="layout">
1654 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1655 <td class="left">12x10 array of single precision floating point values.</td>
1656 </tr>
1657 <tr class="layout">
1658 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1659 <td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1660 </tr>
1661</table>
1662
Dan Gohman87ec5ad2009-11-09 19:01:53 +0000[diff] [blame]1663<p>There is no restriction on indexing beyond the end of the array implied by
1664 a static type (though there are restrictions on indexing beyond the bounds
1665 of an allocated object in some cases). This means that single-dimension
1666 'variable sized array' addressing can be implemented in LLVM with a zero
1667 length array type. An implementation of 'pascal style arrays' in LLVM could
1668 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1669
1670</div>
1671
1672<!-- _______________________________________________________________________ -->
1673<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1674
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1675<div class="doc_text">
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1676
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1677<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1678<p>The function type can be thought of as a function signature. It consists of
1679 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]1680 function type is a scalar type, a void type, a struct type, or a union
1681 type. If the return type is a struct type then all struct elements must be
1682 of first class types, and the struct must have at least one element.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1683
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1684<h5>Syntax:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1685<pre>
Nick Lewycky3b3b54d2009-09-27 07:55:32 +0000[diff] [blame]1686 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1687</pre>
1688
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1689<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]1690 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1691 which indicates that the function takes a variable number of arguments.
1692 Variable argument functions can access their arguments with
1693 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner553fb1e2010-03-02 06:36:51 +0000[diff] [blame]1694 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewyckyeb021882009-09-27 23:27:42 +0000[diff] [blame]1695 <a href="#t_label">label</a>.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1696
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1697<h5>Examples:</h5>
1698<table class="layout">
1699 <tr class="layout">
1700 <td class="left"><tt>i32 (i32)</tt></td>
1701 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
1702 </td>
1703 </tr><tr class="layout">
Chris Lattner553fb1e2010-03-02 06:36:51 +0000[diff] [blame]1704 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1705 </tt></td>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1706 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner553fb1e2010-03-02 06:36:51 +0000[diff] [blame]1707 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
1708 returning <tt>float</tt>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1709 </td>
1710 </tr><tr class="layout">
1711 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1712 <td class="left">A vararg function that takes at least one
1713 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1714 which returns an integer. This is the signature for <tt>printf</tt> in
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1715 LLVM.
1716 </td>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1717 </tr><tr class="layout">
1718 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky3b3b54d2009-09-27 07:55:32 +0000[diff] [blame]1719 <td class="left">A function taking an <tt>i32</tt>, returning a
1720 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1721 </td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1722 </tr>
1723</table>
1724
1725</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1726
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1727<!-- _______________________________________________________________________ -->
1728<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1729
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1730<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1731
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1732<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1733<p>The structure type is used to represent a collection of data members together
1734 in memory. The packing of the field types is defined to match the ABI of the
1735 underlying processor. The elements of a structure may be any type that has a
1736 size.</p>
1737
Jeffrey Yasskine05d7732010-01-11 19:19:26 +0000[diff] [blame]1738<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
1739 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
1740 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1741 Structures in registers are accessed using the
1742 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
1743 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1744<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1745<pre>
1746 { &lt;type list&gt; }
1747</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1748
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1749<h5>Examples:</h5>
1750<table class="layout">
1751 <tr class="layout">
1752 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1753 <td class="left">A triple of three <tt>i32</tt> values</td>
1754 </tr><tr class="layout">
1755 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1756 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1757 second element is a <a href="#t_pointer">pointer</a> to a
1758 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1759 an <tt>i32</tt>.</td>
1760 </tr>
1761</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1762
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1763</div>
1764
1765<!-- _______________________________________________________________________ -->
1766<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1767</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1768
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1769<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1770
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1771<h5>Overview:</h5>
1772<p>The packed structure type is used to represent a collection of data members
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1773 together in memory. There is no padding between fields. Further, the
1774 alignment of a packed structure is 1 byte. The elements of a packed
1775 structure may be any type that has a size.</p>
1776
1777<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1778 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1779 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1780
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1781<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1782<pre>
1783 &lt; { &lt;type list&gt; } &gt;
1784</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1785
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1786<h5>Examples:</h5>
1787<table class="layout">
1788 <tr class="layout">
1789 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1790 <td class="left">A triple of three <tt>i32</tt> values</td>
1791 </tr><tr class="layout">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1792 <td class="left">
1793<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1794 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1795 second element is a <a href="#t_pointer">pointer</a> to a
1796 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1797 an <tt>i32</tt>.</td>
1798 </tr>
1799</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1800
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1801</div>
1802
1803<!-- _______________________________________________________________________ -->
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1804<div class="doc_subsubsection"> <a name="t_union">Union Type</a> </div>
1805
1806<div class="doc_text">
1807
1808<h5>Overview:</h5>
1809<p>A union type describes an object with size and alignment suitable for
1810 an object of any one of a given set of types (also known as an "untagged"
1811 union). It is similar in concept and usage to a
1812 <a href="#t_struct">struct</a>, except that all members of the union
1813 have an offset of zero. The elements of a union may be any type that has a
1814 size. Unions must have at least one member - empty unions are not allowed.
1815 </p>
1816
1817<p>The size of the union as a whole will be the size of its largest member,
1818 and the alignment requirements of the union as a whole will be the largest
1819 alignment requirement of any member.</p>
1820
Dan Gohmanef8400c2010-02-25 16:51:31 +0000[diff] [blame]1821<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]1822 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1823 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1824 Since all members are at offset zero, the getelementptr instruction does
1825 not affect the address, only the type of the resulting pointer.</p>
1826
1827<h5>Syntax:</h5>
1828<pre>
1829 union { &lt;type list&gt; }
1830</pre>
1831
1832<h5>Examples:</h5>
1833<table class="layout">
1834 <tr class="layout">
1835 <td class="left"><tt>union { i32, i32*, float }</tt></td>
1836 <td class="left">A union of three types: an <tt>i32</tt>, a pointer to
1837 an <tt>i32</tt>, and a <tt>float</tt>.</td>
1838 </tr><tr class="layout">
1839 <td class="left">
1840 <tt>union {&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1841 <td class="left">A union, where the first element is a <tt>float</tt> and the
1842 second element is a <a href="#t_pointer">pointer</a> to a
1843 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1844 an <tt>i32</tt>.</td>
1845 </tr>
1846</table>
1847
1848</div>
1849
1850<!-- _______________________________________________________________________ -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1851<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1852
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1853<div class="doc_text">
1854
1855<h5>Overview:</h5>
Dan Gohmanb2f72c82010-02-25 16:50:07 +0000[diff] [blame]1856<p>The pointer type is used to specify memory locations.
1857 Pointers are commonly used to reference objects in memory.</p>
1858
1859<p>Pointer types may have an optional address space attribute defining the
1860 numbered address space where the pointed-to object resides. The default
1861 address space is number zero. The semantics of non-zero address
1862 spaces are target-specific.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1863
1864<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1865 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1866
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1867<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1868<pre>
1869 &lt;type&gt; *
1870</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1871
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1872<h5>Examples:</h5>
1873<table class="layout">
1874 <tr class="layout">
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]1875 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1876 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1877 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1878 </tr>
1879 <tr class="layout">
1880 <td class="left"><tt>i32 (i32 *) *</tt></td>
1881 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1882 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1883 <tt>i32</tt>.</td>
1884 </tr>
1885 <tr class="layout">
1886 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1887 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1888 that resides in address space #5.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1889 </tr>
1890</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1891
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1892</div>
1893
1894<!-- _______________________________________________________________________ -->
1895<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1896
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1897<div class="doc_text">
1898
1899<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1900<p>A vector type is a simple derived type that represents a vector of elements.
1901 Vector types are used when multiple primitive data are operated in parallel
1902 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sands87598b02009-11-27 13:38:03 +0000[diff] [blame]1903 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1904 <a href="#t_firstclass">first class</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1905
1906<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1907<pre>
1908 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1909</pre>
1910
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1911<p>The number of elements is a constant integer value; elementtype may be any
1912 integer or floating point type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1913
1914<h5>Examples:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1915<table class="layout">
1916 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1917 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1918 <td class="left">Vector of 4 32-bit integer values.</td>
1919 </tr>
1920 <tr class="layout">
1921 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1922 <td class="left">Vector of 8 32-bit floating-point values.</td>
1923 </tr>
1924 <tr class="layout">
1925 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1926 <td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1927 </tr>
1928</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1929
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1930</div>
1931
1932<!-- _______________________________________________________________________ -->
1933<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1934<div class="doc_text">
1935
1936<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1937<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1938 corresponds (for example) to the C notion of a forward declared structure
1939 type. In LLVM, opaque types can eventually be resolved to any type (not just
1940 a structure type).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1941
1942<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1943<pre>
1944 opaque
1945</pre>
1946
1947<h5>Examples:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1948<table class="layout">
1949 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1950 <td class="left"><tt>opaque</tt></td>
1951 <td class="left">An opaque type.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1952 </tr>
1953</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1954
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1955</div>
1956
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1957<!-- ======================================================================= -->
1958<div class="doc_subsection">
1959 <a name="t_uprefs">Type Up-references</a>
1960</div>
1961
1962<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1963
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1964<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1965<p>An "up reference" allows you to refer to a lexically enclosing type without
1966 requiring it to have a name. For instance, a structure declaration may
1967 contain a pointer to any of the types it is lexically a member of. Example
1968 of up references (with their equivalent as named type declarations)
1969 include:</p>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1970
1971<pre>
Chris Lattner5ad632d2009-02-09 10:00:56 +0000[diff] [blame]1972 { \2 * } %x = type { %x* }
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1973 { \2 }* %y = type { %y }*
1974 \1* %z = type %z*
1975</pre>
1976
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1977<p>An up reference is needed by the asmprinter for printing out cyclic types
1978 when there is no declared name for a type in the cycle. Because the
1979 asmprinter does not want to print out an infinite type string, it needs a
1980 syntax to handle recursive types that have no names (all names are optional
1981 in llvm IR).</p>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1982
1983<h5>Syntax:</h5>
1984<pre>
1985 \&lt;level&gt;
1986</pre>
1987
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1988<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]1989
1990<h5>Examples:</h5>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1991<table class="layout">
1992 <tr class="layout">
1993 <td class="left"><tt>\1*</tt></td>
1994 <td class="left">Self-referential pointer.</td>
1995 </tr>
1996 <tr class="layout">
1997 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1998 <td class="left">Recursive structure where the upref refers to the out-most
1999 structure.</td>
2000 </tr>
2001</table>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]2002
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2003</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2004
2005<!-- *********************************************************************** -->
2006<div class="doc_section"> <a name="constants">Constants</a> </div>
2007<!-- *********************************************************************** -->
2008
2009<div class="doc_text">
2010
2011<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2012 them all and their syntax.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2013
2014</div>
2015
2016<!-- ======================================================================= -->
2017<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
2018
2019<div class="doc_text">
2020
2021<dl>
2022 <dt><b>Boolean constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2023 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]2024 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2025
2026 <dt><b>Integer constants</b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2027 <dd>Standard integers (such as '4') are constants of
2028 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2029 with integer types.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2030
2031 <dt><b>Floating point constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2032 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2033 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2034 notation (see below). The assembler requires the exact decimal value of a
2035 floating-point constant. For example, the assembler accepts 1.25 but
2036 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2037 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2038
2039 <dt><b>Null pointer constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2040 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2041 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2042</dl>
2043
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2044<p>The one non-intuitive notation for constants is the hexadecimal form of
2045 floating point constants. For example, the form '<tt>double
2046 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2047 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2048 constants are required (and the only time that they are generated by the
2049 disassembler) is when a floating point constant must be emitted but it cannot
2050 be represented as a decimal floating point number in a reasonable number of
2051 digits. For example, NaN's, infinities, and other special values are
2052 represented in their IEEE hexadecimal format so that assembly and disassembly
2053 do not cause any bits to change in the constants.</p>
2054
Dale Johannesenf82a52f2009-02-11 22:14:51 +0000[diff] [blame]2055<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2056 represented using the 16-digit form shown above (which matches the IEEE754
2057 representation for double); float values must, however, be exactly
2058 representable as IEE754 single precision. Hexadecimal format is always used
2059 for long double, and there are three forms of long double. The 80-bit format
2060 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2061 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2062 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2063 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2064 currently supported target uses this format. Long doubles will only work if
2065 they match the long double format on your target. All hexadecimal formats
2066 are big-endian (sign bit at the left).</p>
2067
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2068</div>
2069
2070<!-- ======================================================================= -->
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]2071<div class="doc_subsection">
Bill Wendling1a2630a2009-07-20 02:32:41 +0000[diff] [blame]2072<a name="aggregateconstants"></a> <!-- old anchor -->
2073<a name="complexconstants">Complex Constants</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2074</div>
2075
2076<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2077
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]2078<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2079 constants and smaller complex constants.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2080
2081<dl>
2082 <dt><b>Structure constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2083 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2084 type definitions (a comma separated list of elements, surrounded by braces
2085 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2086 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2087 Structure constants must have <a href="#t_struct">structure type</a>, and
2088 the number and types of elements must match those specified by the
2089 type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2090
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]2091 <dt><b>Union constants</b></dt>
2092 <dd>Union constants are represented with notation similar to a structure with
2093 a single element - that is, a single typed element surrounded
2094 by braces (<tt>{}</tt>)). For example: "<tt>{ i32 4 }</tt>". The
2095 <a href="#t_union">union type</a> can be initialized with a single-element
2096 struct as long as the type of the struct element matches the type of
2097 one of the union members.</dd>
2098
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2099 <dt><b>Array constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2100 <dd>Array constants are represented with notation similar to array type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2101 definitions (a comma separated list of elements, surrounded by square
2102 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2103 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2104 the number and types of elements must match those specified by the
2105 type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2106
2107 <dt><b>Vector constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2108 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2109 definitions (a comma separated list of elements, surrounded by
2110 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2111 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2112 have <a href="#t_vector">vector type</a>, and the number and types of
2113 elements must match those specified by the type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2114
2115 <dt><b>Zero initialization</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2116 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]2117 value to zero of <em>any</em> type, including scalar and
2118 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2119 This is often used to avoid having to print large zero initializers
2120 (e.g. for large arrays) and is always exactly equivalent to using explicit
2121 zero initializers.</dd>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2122
2123 <dt><b>Metadata node</b></dt>
Nick Lewyckyf122c7e2009-05-30 16:08:30 +0000[diff] [blame]2124 <dd>A metadata node is a structure-like constant with
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2125 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2126 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2127 be interpreted as part of the instruction stream, metadata is a place to
2128 attach additional information such as debug info.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2129</dl>
2130
2131</div>
2132
2133<!-- ======================================================================= -->
2134<div class="doc_subsection">
2135 <a name="globalconstants">Global Variable and Function Addresses</a>
2136</div>
2137
2138<div class="doc_text">
2139
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2140<p>The addresses of <a href="#globalvars">global variables</a>
2141 and <a href="#functionstructure">functions</a> are always implicitly valid
2142 (link-time) constants. These constants are explicitly referenced when
2143 the <a href="#identifiers">identifier for the global</a> is used and always
2144 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2145 legal LLVM file:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2146
2147<div class="doc_code">
2148<pre>
2149@X = global i32 17
2150@Y = global i32 42
2151@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
2152</pre>
2153</div>
2154
2155</div>
2156
2157<!-- ======================================================================= -->
2158<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
2159<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2160
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2161<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]2162 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2163 Undefined values may be of any type (other than label or void) and be used
2164 anywhere a constant is permitted.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2165
Chris Lattner9d1e4fa2009-09-11 01:49:31 +0000[diff] [blame]2166<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2167 program is well defined no matter what value is used. This gives the
2168 compiler more freedom to optimize. Here are some examples of (potentially
2169 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2170
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2171
2172<div class="doc_code">
2173<pre>
2174 %A = add %X, undef
2175 %B = sub %X, undef
2176 %C = xor %X, undef
2177Safe:
2178 %A = undef
2179 %B = undef
2180 %C = undef
2181</pre>
2182</div>
2183
2184<p>This is safe because all of the output bits are affected by the undef bits.
2185Any output bit can have a zero or one depending on the input bits.</p>
2186
2187<div class="doc_code">
2188<pre>
2189 %A = or %X, undef
2190 %B = and %X, undef
2191Safe:
2192 %A = -1
2193 %B = 0
2194Unsafe:
2195 %A = undef
2196 %B = undef
2197</pre>
2198</div>
2199
2200<p>These logical operations have bits that are not always affected by the input.
2201For example, if "%X" has a zero bit, then the output of the 'and' operation will
2202always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattner9d1e4fa2009-09-11 01:49:31 +0000[diff] [blame]2203such, 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]2204However, it is safe to assume that all bits of the undef could be 0, and
2205optimize the and to 0. Likewise, it is safe to assume that all the bits of
2206the 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]2207-1.</p>
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2208
2209<div class="doc_code">
2210<pre>
2211 %A = select undef, %X, %Y
2212 %B = select undef, 42, %Y
2213 %C = select %X, %Y, undef
2214Safe:
2215 %A = %X (or %Y)
2216 %B = 42 (or %Y)
2217 %C = %Y
2218Unsafe:
2219 %A = undef
2220 %B = undef
2221 %C = undef
2222</pre>
2223</div>
2224
2225<p>This set of examples show that undefined select (and conditional branch)
2226conditions can go "either way" but they have to come from one of the two
2227operands. In the %A example, if %X and %Y were both known to have a clear low
2228bit, then %A would have to have a cleared low bit. However, in the %C example,
2229the optimizer is allowed to assume that the undef operand could be the same as
2230%Y, allowing the whole select to be eliminated.</p>
2231
2232
2233<div class="doc_code">
2234<pre>
2235 %A = xor undef, undef
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2236
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2237 %B = undef
2238 %C = xor %B, %B
2239
2240 %D = undef
2241 %E = icmp lt %D, 4
2242 %F = icmp gte %D, 4
2243
2244Safe:
2245 %A = undef
2246 %B = undef
2247 %C = undef
2248 %D = undef
2249 %E = undef
2250 %F = undef
2251</pre>
2252</div>
2253
2254<p>This example points out that two undef operands are not necessarily the same.
2255This can be surprising to people (and also matches C semantics) where they
2256assume that "X^X" is always zero, even if X is undef. This isn't true for a
2257number of reasons, but the short answer is that an undef "variable" can
2258arbitrarily change its value over its "live range". This is true because the
2259"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2260logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2261so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattnerc802e482009-09-08 15:13:16 +0000[diff] [blame]2262to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2263would not hold.</p>
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2264
2265<div class="doc_code">
2266<pre>
2267 %A = fdiv undef, %X
2268 %B = fdiv %X, undef
2269Safe:
2270 %A = undef
2271b: unreachable
2272</pre>
2273</div>
2274
2275<p>These examples show the crucial difference between an <em>undefined
2276value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2277allowed to have an arbitrary bit-pattern. This means that the %A operation
2278can be constant folded to undef because the undef could be an SNaN, and fdiv is
2279not (currently) defined on SNaN's. However, in the second example, we can make
2280a more aggressive assumption: because the undef is allowed to be an arbitrary
2281value, 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]2282has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2283does not execute at all. This allows us to delete the divide and all code after
2284it: since the undefined operation "can't happen", the optimizer can assume that
2285it occurs in dead code.
2286</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2287
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2288<div class="doc_code">
2289<pre>
2290a: store undef -> %X
2291b: store %X -> undef
2292Safe:
2293a: &lt;deleted&gt;
2294b: unreachable
2295</pre>
2296</div>
2297
2298<p>These examples reiterate the fdiv example: a store "of" an undefined value
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2299can be assumed to not have any effect: we can assume that the value is
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2300overwritten with bits that happen to match what was already there. However, a
2301store "to" an undefined location could clobber arbitrary memory, therefore, it
2302has undefined behavior.</p>
2303
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2304</div>
2305
2306<!-- ======================================================================= -->
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]2307<div class="doc_subsection"><a name="trapvalues">Trap Values</a></div>
2308<div class="doc_text">
2309
2310<p>Trap values are similar to <a href="undefvalues">undef values</a>, however
2311 instead of representing an unspecified bit pattern, they represent the
2312 fact that an instruction or constant expression which cannot evoke side
2313 effects has nevertheless detected a condition which results in undefined
2314 behavior.<p>
2315
2316<p>Any non-void instruction or constant expression other than non-intrinsic
2317 calls or invokes with a trap operand has trap as its result value.
2318 Any instruction with a trap operand which may have side effects emits
2319 those side effects as if it had an undef operand instead.</p>
2320
2321<p>For example, an <a href="#i_and"><tt>and</tt></a> of a trap value with
2322 zero still has a trap value result. Using that value as an index in a
2323 <a href="#i_getelementptr"><tt>getelementptr</tt></a> yields a trap
2324 result. Using that result as the address of a
2325 <a href="#i_store"><tt>store</tt></a> produces undefined behavior.</p>
2326
2327<p>There is currently no way of representing a trap constant in the IR; they
2328 only exist when produced by certain instructions, such as an
2329 <a href="#i_add"><tt>add</tt></a> with the <tt>nsw</tt> flag
2330 set, when overflow occurs.</p>
2331
2332</div>
2333
2334<!-- ======================================================================= -->
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]2335<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2336 Blocks</a></div>
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2337<div class="doc_text">
2338
Chris Lattner620cead2009-11-01 01:27:45 +0000[diff] [blame]2339<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2340
2341<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner24f2e852009-10-27 21:49:40 +0000[diff] [blame]2342 basic block in the specified function, and always has an i8* type. Taking
Chris Lattner620cead2009-11-01 01:27:45 +0000[diff] [blame]2343 the address of the entry block is illegal.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2344
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2345<p>This value only has defined behavior when used as an operand to the
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2346 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2347 against null. Pointer equality tests between labels addresses is undefined
2348 behavior - though, again, comparison against null is ok, and no label is
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]2349 equal to the null pointer. This may also be passed around as an opaque
2350 pointer sized value as long as the bits are not inspected. This allows
Chris Lattner0bae7b32009-10-27 21:44:20 +0000[diff] [blame]2351 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2352 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2353
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]2354<p>Finally, some targets may provide defined semantics when
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2355 using the value as the operand to an inline assembly, but that is target
2356 specific.
2357 </p>
2358
2359</div>
2360
2361
2362<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2363<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2364</div>
2365
2366<div class="doc_text">
2367
2368<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2369 to be used as constants. Constant expressions may be of
2370 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2371 operation that does not have side effects (e.g. load and call are not
2372 supported). The following is the syntax for constant expressions:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2373
2374<dl>
2375 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2376 <dd>Truncate a constant to another type. The bit size of CST must be larger
2377 than the bit size of TYPE. Both types must be integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2378
2379 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2380 <dd>Zero extend a constant to another type. The bit size of CST must be
2381 smaller or equal to the bit size of TYPE. Both types must be
2382 integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2383
2384 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2385 <dd>Sign extend a constant to another type. The bit size of CST must be
2386 smaller or equal to the bit size of TYPE. Both types must be
2387 integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2388
2389 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2390 <dd>Truncate a floating point constant to another floating point type. The
2391 size of CST must be larger than the size of TYPE. Both types must be
2392 floating point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2393
2394 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2395 <dd>Floating point extend a constant to another type. The size of CST must be
2396 smaller or equal to the size of TYPE. Both types must be floating
2397 point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2398
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]2399 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2400 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2401 constant. TYPE must be a scalar or vector integer type. CST must be of
2402 scalar or vector floating point type. Both CST and TYPE must be scalars,
2403 or vectors of the same number of elements. If the value won't fit in the
2404 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2405
2406 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
2407 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2408 constant. TYPE must be a scalar or vector integer type. CST must be of
2409 scalar or vector floating point type. Both CST and TYPE must be scalars,
2410 or vectors of the same number of elements. If the value won't fit in the
2411 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2412
2413 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
2414 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2415 constant. TYPE must be a scalar or vector floating point type. CST must be
2416 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2417 vectors of the same number of elements. If the value won't fit in the
2418 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2419
2420 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
2421 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2422 constant. TYPE must be a scalar or vector floating point type. CST must be
2423 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2424 vectors of the same number of elements. If the value won't fit in the
2425 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2426
2427 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2428 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2429 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2430 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2431 make it fit in <tt>TYPE</tt>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2432
2433 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2434 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2435 type. CST must be of integer type. The CST value is zero extended,
2436 truncated, or unchanged to make it fit in a pointer size. This one is
2437 <i>really</i> dangerous!</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2438
2439 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner557bc5d2009-02-28 18:27:03 +0000[diff] [blame]2440 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2441 are the same as those for the <a href="#i_bitcast">bitcast
2442 instruction</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2443
2444 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]2445 <dt><b><tt>getelementptr inbounds ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2446 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2447 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2448 instruction, the index list may have zero or more indexes, which are
2449 required to make sense for the type of "CSTPTR".</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2450
2451 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2452 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2453
2454 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2455 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2456
2457 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2458 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
2459
2460 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2461 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2462 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2463
2464 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2465 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2466 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2467
2468 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2469 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2470 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2471
2472 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2473 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2474 be any of the <a href="#binaryops">binary</a>
2475 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2476 on operands are the same as those for the corresponding instruction
2477 (e.g. no bitwise operations on floating point values are allowed).</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2478</dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2479
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2480</div>
2481
2482<!-- *********************************************************************** -->
2483<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2484<!-- *********************************************************************** -->
2485
2486<!-- ======================================================================= -->
2487<div class="doc_subsection">
2488<a name="inlineasm">Inline Assembler Expressions</a>
2489</div>
2490
2491<div class="doc_text">
2492
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2493<p>LLVM supports inline assembler expressions (as opposed
2494 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2495 a special value. This value represents the inline assembler as a string
2496 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2497 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2498 expression has side effects, and a flag indicating whether the function
2499 containing the asm needs to align its stack conservatively. An example
2500 inline assembler expression is:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2501
2502<div class="doc_code">
2503<pre>
2504i32 (i32) asm "bswap $0", "=r,r"
2505</pre>
2506</div>
2507
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2508<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2509 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2510 have:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2511
2512<div class="doc_code">
2513<pre>
2514%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
2515</pre>
2516</div>
2517
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2518<p>Inline asms with side effects not visible in the constraint list must be
2519 marked as having side effects. This is done through the use of the
2520 '<tt>sideeffect</tt>' keyword, like so:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2521
2522<div class="doc_code">
2523<pre>
2524call void asm sideeffect "eieio", ""()
2525</pre>
2526</div>
2527
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2528<p>In some cases inline asms will contain code that will not work unless the
2529 stack is aligned in some way, such as calls or SSE instructions on x86,
2530 yet will not contain code that does that alignment within the asm.
2531 The compiler should make conservative assumptions about what the asm might
2532 contain and should generate its usual stack alignment code in the prologue
2533 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2534
2535<div class="doc_code">
2536<pre>
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2537call void asm alignstack "eieio", ""()
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2538</pre>
2539</div>
2540
2541<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2542 first.</p>
2543
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2544<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2545 documented here. Constraints on what can be done (e.g. duplication, moving,
2546 etc need to be documented). This is probably best done by reference to
2547 another document that covers inline asm from a holistic perspective.</p>
Chris Lattnerbafc8372010-04-07 05:38:05 +0000[diff] [blame]2548</div>
2549
2550<div class="doc_subsubsection">
2551<a name="inlineasm_md">Inline Asm Metadata</a>
2552</div>
2553
2554<div class="doc_text">
2555
2556<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
2557 attached to it that contains a constant integer. If present, the code
2558 generator will use the integer as the location cookie value when report
2559 errors through the LLVMContext error reporting mechanisms. This allows a
2560 front-end to corrolate backend errors that occur with inline asm back to the
2561 source code that produced it. For example:</p>
2562
2563<div class="doc_code">
2564<pre>
2565call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2566...
2567!42 = !{ i32 1234567 }
2568</pre>
2569</div>
2570
2571<p>It is up to the front-end to make sense of the magic numbers it places in the
2572 IR.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2573
2574</div>
2575
Chris Lattnerd0d96292010-01-15 21:50:19 +0000[diff] [blame]2576<!-- ======================================================================= -->
2577<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
2578 Strings</a>
2579</div>
2580
2581<div class="doc_text">
2582
2583<p>LLVM IR allows metadata to be attached to instructions in the program that
2584 can convey extra information about the code to the optimizers and code
2585 generator. One example application of metadata is source-level debug
2586 information. There are two metadata primitives: strings and nodes. All
2587 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2588 preceding exclamation point ('<tt>!</tt>').</p>
2589
2590<p>A metadata string is a string surrounded by double quotes. It can contain
2591 any character by escaping non-printable characters with "\xx" where "xx" is
2592 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2593
2594<p>Metadata nodes are represented with notation similar to structure constants
2595 (a comma separated list of elements, surrounded by braces and preceded by an
2596 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2597 10}</tt>". Metadata nodes can have any values as their operand.</p>
2598
2599<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2600 metadata nodes, which can be looked up in the module symbol table. For
2601 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2602
Devang Patelb1586922010-03-04 23:44:48 +0000[diff] [blame]2603<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
2604 function is using two metadata arguments.
2605
2606 <div class="doc_code">
2607 <pre>
2608 call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2609 </pre>
2610 </div></p>
2611
2612<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
2613 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.
2614
2615 <div class="doc_code">
2616 <pre>
2617 %indvar.next = add i64 %indvar, 1, !dbg !21
2618 </pre>
2619 </div></p>
Chris Lattnerd0d96292010-01-15 21:50:19 +0000[diff] [blame]2620</div>
2621
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2622
2623<!-- *********************************************************************** -->
2624<div class="doc_section">
2625 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2626</div>
2627<!-- *********************************************************************** -->
2628
2629<p>LLVM has a number of "magic" global variables that contain data that affect
2630code generation or other IR semantics. These are documented here. All globals
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2631of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2632section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2633by LLVM.</p>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2634
2635<!-- ======================================================================= -->
2636<div class="doc_subsection">
2637<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2638</div>
2639
2640<div class="doc_text">
2641
2642<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2643href="#linkage_appending">appending linkage</a>. This array contains a list of
2644pointers to global variables and functions which may optionally have a pointer
2645cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2646
2647<pre>
2648 @X = global i8 4
2649 @Y = global i32 123
2650
2651 @llvm.used = appending global [2 x i8*] [
2652 i8* @X,
2653 i8* bitcast (i32* @Y to i8*)
2654 ], section "llvm.metadata"
2655</pre>
2656
2657<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2658compiler, assembler, and linker are required to treat the symbol as if there is
2659a reference to the global that it cannot see. For example, if a variable has
2660internal linkage and no references other than that from the <tt>@llvm.used</tt>
2661list, it cannot be deleted. This is commonly used to represent references from
2662inline asms and other things the compiler cannot "see", and corresponds to
2663"attribute((used))" in GNU C.</p>
2664
2665<p>On some targets, the code generator must emit a directive to the assembler or
2666object file to prevent the assembler and linker from molesting the symbol.</p>
2667
2668</div>
2669
2670<!-- ======================================================================= -->
2671<div class="doc_subsection">
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2672<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2673</div>
2674
2675<div class="doc_text">
2676
2677<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2678<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2679touching the symbol. On targets that support it, this allows an intelligent
2680linker to optimize references to the symbol without being impeded as it would be
2681by <tt>@llvm.used</tt>.</p>
2682
2683<p>This is a rare construct that should only be used in rare circumstances, and
2684should not be exposed to source languages.</p>
2685
2686</div>
2687
2688<!-- ======================================================================= -->
2689<div class="doc_subsection">
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2690<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2691</div>
2692
2693<div class="doc_text">
2694
2695<p>TODO: Describe this.</p>
2696
2697</div>
2698
2699<!-- ======================================================================= -->
2700<div class="doc_subsection">
2701<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2702</div>
2703
2704<div class="doc_text">
2705
2706<p>TODO: Describe this.</p>
2707
2708</div>
2709
2710
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2711<!-- *********************************************************************** -->
2712<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2713<!-- *********************************************************************** -->
2714
2715<div class="doc_text">
2716
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2717<p>The LLVM instruction set consists of several different classifications of
2718 instructions: <a href="#terminators">terminator
2719 instructions</a>, <a href="#binaryops">binary instructions</a>,
2720 <a href="#bitwiseops">bitwise binary instructions</a>,
2721 <a href="#memoryops">memory instructions</a>, and
2722 <a href="#otherops">other instructions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2723
2724</div>
2725
2726<!-- ======================================================================= -->
2727<div class="doc_subsection"> <a name="terminators">Terminator
2728Instructions</a> </div>
2729
2730<div class="doc_text">
2731
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2732<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2733 in a program ends with a "Terminator" instruction, which indicates which
2734 block should be executed after the current block is finished. These
2735 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2736 control flow, not values (the one exception being the
2737 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2738
Duncan Sands048d8062010-04-15 20:35:54 +0000[diff] [blame]2739<p>There are seven different terminator instructions: the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2740 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2741 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2742 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendlingb4ae2292009-11-02 00:25:26 +0000[diff] [blame]2743 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2744 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2745 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2746 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2747
2748</div>
2749
2750<!-- _______________________________________________________________________ -->
2751<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2752Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2753
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2754<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2755
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2756<h5>Syntax:</h5>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2757<pre>
2758 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]2759 ret void <i>; Return from void function</i>
2760</pre>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2761
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2762<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2763<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2764 a value) from a function back to the caller.</p>
2765
2766<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2767 value and then causes control flow, and one that just causes control flow to
2768 occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2769
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2770<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2771<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2772 return value. The type of the return value must be a
2773 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2774
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2775<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2776 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2777 value or a return value with a type that does not match its type, or if it
2778 has a void return type and contains a '<tt>ret</tt>' instruction with a
2779 return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2780
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2781<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2782<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2783 the calling function's context. If the caller is a
2784 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2785 instruction after the call. If the caller was an
2786 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2787 the beginning of the "normal" destination block. If the instruction returns
2788 a value, that value shall set the call or invoke instruction's return
2789 value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2790
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2791<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2792<pre>
2793 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2794 ret void <i>; Return from a void function</i>
Bill Wendlingd163e2d2009-02-28 22:12:54 +0000[diff] [blame]2795 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]2796</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2797
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2798</div>
2799<!-- _______________________________________________________________________ -->
2800<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2801
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2802<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2803
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2804<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2805<pre>
2806 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]2807</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2808
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2809<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2810<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2811 different basic block in the current function. There are two forms of this
2812 instruction, corresponding to a conditional branch and an unconditional
2813 branch.</p>
2814
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2815<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2816<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2817 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2818 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2819 target.</p>
2820
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2821<h5>Semantics:</h5>
2822<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2823 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2824 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2825 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2826
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2827<h5>Example:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]2828<pre>
2829Test:
2830 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2831 br i1 %cond, label %IfEqual, label %IfUnequal
2832IfEqual:
2833 <a href="#i_ret">ret</a> i32 1
2834IfUnequal:
2835 <a href="#i_ret">ret</a> i32 0
2836</pre>
2837
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2838</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2839
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2840<!-- _______________________________________________________________________ -->
2841<div class="doc_subsubsection">
2842 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2843</div>
2844
2845<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2846
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2847<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2848<pre>
2849 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2850</pre>
2851
2852<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2853<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]2854 several different places. It is a generalization of the '<tt>br</tt>'
2855 instruction, allowing a branch to occur to one of many possible
2856 destinations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2857
2858<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2859<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2860 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2861 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2862 The table is not allowed to contain duplicate constant entries.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2863
2864<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2865<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2866 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2867 is searched for the given value. If the value is found, control flow is
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2868 transferred to the corresponding destination; otherwise, control flow is
2869 transferred to the default destination.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2870
2871<h5>Implementation:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2872<p>Depending on properties of the target machine and the particular
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2873 <tt>switch</tt> instruction, this instruction may be code generated in
2874 different ways. For example, it could be generated as a series of chained
2875 conditional branches or with a lookup table.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2876
2877<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2878<pre>
2879 <i>; Emulate a conditional br instruction</i>
2880 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2881 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2882
2883 <i>; Emulate an unconditional br instruction</i>
2884 switch i32 0, label %dest [ ]
2885
2886 <i>; Implement a jump table:</i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2887 switch i32 %val, label %otherwise [ i32 0, label %onzero
2888 i32 1, label %onone
2889 i32 2, label %ontwo ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2890</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2891
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2892</div>
2893
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2894
2895<!-- _______________________________________________________________________ -->
2896<div class="doc_subsubsection">
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2897 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2898</div>
2899
2900<div class="doc_text">
2901
2902<h5>Syntax:</h5>
2903<pre>
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2904 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]2905</pre>
2906
2907<h5>Overview:</h5>
2908
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2909<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2910 within the current function, whose address is specified by
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2911 "<tt>address</tt>". Address must be derived from a <a
2912 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2913
2914<h5>Arguments:</h5>
2915
2916<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
2917 rest of the arguments indicate the full set of possible destinations that the
2918 address may point to. Blocks are allowed to occur multiple times in the
2919 destination list, though this isn't particularly useful.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2920
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2921<p>This destination list is required so that dataflow analysis has an accurate
2922 understanding of the CFG.</p>
2923
2924<h5>Semantics:</h5>
2925
2926<p>Control transfers to the block specified in the address argument. All
2927 possible destination blocks must be listed in the label list, otherwise this
2928 instruction has undefined behavior. This implies that jumps to labels
2929 defined in other functions have undefined behavior as well.</p>
2930
2931<h5>Implementation:</h5>
2932
2933<p>This is typically implemented with a jump through a register.</p>
2934
2935<h5>Example:</h5>
2936<pre>
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2937 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2938</pre>
2939
2940</div>
2941
2942
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2943<!-- _______________________________________________________________________ -->
2944<div class="doc_subsubsection">
2945 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2946</div>
2947
2948<div class="doc_text">
2949
2950<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2951<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2952 &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]2953 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
2954</pre>
2955
2956<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2957<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2958 function, with the possibility of control flow transfer to either the
2959 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
2960 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
2961 control flow will return to the "normal" label. If the callee (or any
2962 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
2963 instruction, control is interrupted and continued at the dynamically nearest
2964 "exception" label.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2965
2966<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2967<p>This instruction requires several arguments:</p>
2968
2969<ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2970 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
2971 convention</a> the call should use. If none is specified, the call
2972 defaults to using C calling conventions.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2973
2974 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2975 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
2976 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2977
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2978 <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]2979 function value being invoked. In most cases, this is a direct function
2980 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
2981 off an arbitrary pointer to function value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2982
2983 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2984 function to be invoked. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2985
2986 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner553fb1e2010-03-02 06:36:51 +0000[diff] [blame]2987 signature argument types and parameter attributes. All arguments must be
2988 of <a href="#t_firstclass">first class</a> type. If the function
2989 signature indicates the function accepts a variable number of arguments,
2990 the extra arguments can be specified.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2991
2992 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2993 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2994
2995 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2996 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2997
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2998 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2999 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3000 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3001</ol>
3002
3003<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3004<p>This instruction is designed to operate as a standard
3005 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3006 primary difference is that it establishes an association with a label, which
3007 is used by the runtime library to unwind the stack.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3008
3009<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3010 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3011 exception. Additionally, this is important for implementation of
3012 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3013
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3014<p>For the purposes of the SSA form, the definition of the value returned by the
3015 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3016 block to the "normal" label. If the callee unwinds then no return value is
3017 available.</p>
Dan Gohman140ba5d2009-05-22 21:47:08 +0000[diff] [blame]3018
Chris Lattner4a91ef42010-01-15 18:08:37 +0000[diff] [blame]3019<p>Note that the code generator does not yet completely support unwind, and
3020that the invoke/unwind semantics are likely to change in future versions.</p>
3021
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3022<h5>Example:</h5>
3023<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]3024 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3025 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]3026 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3027 unwind label %TestCleanup <i>; {i32}:retval set</i>
3028</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3029
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3030</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3031
3032<!-- _______________________________________________________________________ -->
3033
3034<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
3035Instruction</a> </div>
3036
3037<div class="doc_text">
3038
3039<h5>Syntax:</h5>
3040<pre>
3041 unwind
3042</pre>
3043
3044<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3045<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3046 at the first callee in the dynamic call stack which used
3047 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3048 This is primarily used to implement exception handling.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3049
3050<h5>Semantics:</h5>
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3051<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3052 immediately halt. The dynamic call stack is then searched for the
3053 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3054 Once found, execution continues at the "exceptional" destination block
3055 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3056 instruction in the dynamic call chain, undefined behavior results.</p>
3057
Chris Lattner4a91ef42010-01-15 18:08:37 +0000[diff] [blame]3058<p>Note that the code generator does not yet completely support unwind, and
3059that the invoke/unwind semantics are likely to change in future versions.</p>
3060
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3061</div>
3062
3063<!-- _______________________________________________________________________ -->
3064
3065<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
3066Instruction</a> </div>
3067
3068<div class="doc_text">
3069
3070<h5>Syntax:</h5>
3071<pre>
3072 unreachable
3073</pre>
3074
3075<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3076<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3077 instruction is used to inform the optimizer that a particular portion of the
3078 code is not reachable. This can be used to indicate that the code after a
3079 no-return function cannot be reached, and other facts.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3080
3081<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3082<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3083
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3084</div>
3085
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3086<!-- ======================================================================= -->
3087<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3088
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3089<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3090
3091<p>Binary operators are used to do most of the computation in a program. They
3092 require two operands of the same type, execute an operation on them, and
3093 produce a single value. The operands might represent multiple data, as is
3094 the case with the <a href="#t_vector">vector</a> data type. The result value
3095 has the same type as its operands.</p>
3096
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3097<p>There are several different binary operators:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3098
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3099</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3100
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3101<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3102<div class="doc_subsubsection">
3103 <a name="i_add">'<tt>add</tt>' Instruction</a>
3104</div>
3105
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3106<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3107
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3108<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3109<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3110 &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]3111 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3112 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3113 &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]3114</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3115
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3116<h5>Overview:</h5>
3117<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3118
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3119<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3120<p>The two arguments to the '<tt>add</tt>' instruction must
3121 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3122 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3123
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3124<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3125<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3126
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3127<p>If the sum has unsigned overflow, the result returned is the mathematical
3128 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]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>add</tt>
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]3136 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3137 respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3138
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3139<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3140<pre>
3141 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]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>
Bill Wendlingf85859d2009-07-20 02:29:24 +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_fadd">'<tt>fadd</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; = fadd &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>fadd</tt>' instruction returns the sum of its two operands.</p>
3160
3161<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3162<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3163 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3164 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3165
3166<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3167<p>The value produced is the floating point sum of the two operands.</p>
3168
3169<h5>Example:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3170<pre>
3171 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3172</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3173
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3174</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3175
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3176<!-- _______________________________________________________________________ -->
3177<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3178 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3179</div>
3180
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3181<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3182
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3183<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3184<pre>
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3185 &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]3186 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3187 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3188 &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]3189</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3190
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3191<h5>Overview:</h5>
3192<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3193 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3194
3195<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3196 '<tt>neg</tt>' instruction present in most other intermediate
3197 representations.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3198
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3199<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3200<p>The two arguments to the '<tt>sub</tt>' instruction must
3201 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3202 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3203
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3204<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3205<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3206
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3207<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3208 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3209 result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3210
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3211<p>Because LLVM integers use a two's complement representation, this instruction
3212 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3213
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3214<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3215 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3216 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]3217 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3218 respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3219
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3220<h5>Example:</h5>
3221<pre>
3222 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
3223 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
3224</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3225
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3226</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3227
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3228<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3229<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3230 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3231</div>
3232
3233<div class="doc_text">
3234
3235<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3236<pre>
3237 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3238</pre>
3239
3240<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3241<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3242 operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3243
3244<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3245 '<tt>fneg</tt>' instruction present in most other intermediate
3246 representations.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3247
3248<h5>Arguments:</h5>
Bill Wendling1a2630a2009-07-20 02:32:41 +0000[diff] [blame]3249<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3250 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3251 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3252
3253<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3254<p>The value produced is the floating point difference of the two operands.</p>
3255
3256<h5>Example:</h5>
3257<pre>
3258 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3259 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3260</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3261
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3262</div>
3263
3264<!-- _______________________________________________________________________ -->
3265<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3266 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3267</div>
3268
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3269<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3270
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3271<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3272<pre>
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3273 &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]3274 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3275 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3276 &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]3277</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3278
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3279<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3280<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3281
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3282<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3283<p>The two arguments to the '<tt>mul</tt>' instruction must
3284 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3285 integer values. Both arguments must have identical types.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3286
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3287<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3288<p>The value produced is the integer product of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3289
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3290<p>If the result of the multiplication has unsigned overflow, the result
3291 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3292 width of the result.</p>
3293
3294<p>Because LLVM integers use a two's complement representation, and the result
3295 is the same width as the operands, this instruction returns the correct
3296 result for both signed and unsigned integers. If a full product
3297 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3298 be sign-extended or zero-extended as appropriate to the width of the full
3299 product.</p>
3300
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3301<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3302 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3303 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]3304 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3305 respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3306
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3307<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3308<pre>
3309 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3310</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3311
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3312</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3313
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3314<!-- _______________________________________________________________________ -->
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3315<div class="doc_subsubsection">
3316 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3317</div>
3318
3319<div class="doc_text">
3320
3321<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3322<pre>
3323 &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]3324</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3325
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3326<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3327<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3328
3329<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3330<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3331 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3332 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3333
3334<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3335<p>The value produced is the floating point product of the two operands.</p>
3336
3337<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3338<pre>
3339 &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]3340</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3341
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3342</div>
3343
3344<!-- _______________________________________________________________________ -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3345<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3346</a></div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3347
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3348<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3349
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3350<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3351<pre>
3352 &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]3353</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3354
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3355<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3356<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3357
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3358<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3359<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3360 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3361 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3362
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3363<h5>Semantics:</h5>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3364<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3365
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3366<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3367 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3368
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3369<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3370
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3371<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3372<pre>
3373 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3374</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3375
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3376</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3377
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3378<!-- _______________________________________________________________________ -->
3379<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3380</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3381
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3382<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3383
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3384<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3385<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3386 &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]3387 &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]3388</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3389
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3390<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3391<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3392
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3393<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3394<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3395 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3396 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3397
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3398<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3399<p>The value produced is the signed integer quotient of the two operands rounded
3400 towards zero.</p>
3401
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3402<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3403 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3404
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3405<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3406 undefined behavior; this is a rare case, but can occur, for example, by doing
3407 a 32-bit division of -2147483648 by -1.</p>
3408
Dan Gohman67fa48e2009-07-22 00:04:19 +0000[diff] [blame]3409<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohmanf7263862010-04-23 15:23:32 +0000[diff] [blame^]3410 <tt>sdiv</tt> is a <a href="#trapvalues">trap value</a> if the result would
3411 be rounded or if overflow would occur.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3412
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3413<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3414<pre>
3415 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3416</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3417
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3418</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3419
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3420<!-- _______________________________________________________________________ -->
3421<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
3422Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3423
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3424<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3425
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3426<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3427<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3428 &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]3429</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3430
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3431<h5>Overview:</h5>
3432<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3433
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3434<h5>Arguments:</h5>
3435<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3436 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3437 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3438
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3439<h5>Semantics:</h5>
3440<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3441
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3442<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3443<pre>
3444 &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]3445</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3446
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3447</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3448
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3449<!-- _______________________________________________________________________ -->
3450<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3451</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3452
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3453<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3454
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3455<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3456<pre>
3457 &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]3458</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3459
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3460<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3461<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3462 division of its two arguments.</p>
3463
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3464<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3465<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3466 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3467 values. Both arguments must have identical types.</p>
3468
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3469<h5>Semantics:</h5>
3470<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3471 This instruction always performs an unsigned division to get the
3472 remainder.</p>
3473
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3474<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3475 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3476
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3477<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3478
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3479<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3480<pre>
3481 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3482</pre>
3483
3484</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3485
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3486<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3487<div class="doc_subsubsection">
3488 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3489</div>
3490
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3491<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3492
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3493<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3494<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3495 &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]3496</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3497
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3498<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3499<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3500 division of its two operands. This instruction can also take
3501 <a href="#t_vector">vector</a> versions of the values in which case the
3502 elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]3503
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3504<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3505<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3506 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3507 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3508
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3509<h5>Semantics:</h5>
3510<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3511 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3512 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3513 a value. For more information about the difference,
3514 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3515 Math Forum</a>. For a table of how this is implemented in various languages,
3516 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3517 Wikipedia: modulo operation</a>.</p>
3518
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3519<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3520 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3521
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3522<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3523 Overflow also leads to undefined behavior; this is a rare case, but can
3524 occur, for example, by taking the remainder of a 32-bit division of
3525 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3526 lets srem be implemented using instructions that return both the result of
3527 the division and the remainder.)</p>
3528
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3529<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3530<pre>
3531 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3532</pre>
3533
3534</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3535
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3536<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3537<div class="doc_subsubsection">
3538 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3539
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3540<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3541
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3542<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3543<pre>
3544 &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]3545</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3546
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3547<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3548<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3549 its two operands.</p>
3550
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3551<h5>Arguments:</h5>
3552<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3553 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3554 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3555
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3556<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3557<p>This instruction returns the <i>remainder</i> of a division. The remainder
3558 has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3559
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3560<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3561<pre>
3562 &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]3563</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3564
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3565</div>
3566
3567<!-- ======================================================================= -->
3568<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3569Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3570
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3571<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3572
3573<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3574 program. They are generally very efficient instructions and can commonly be
3575 strength reduced from other instructions. They require two operands of the
3576 same type, execute an operation on them, and produce a single value. The
3577 resulting value is the same type as its operands.</p>
3578
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3579</div>
3580
3581<!-- _______________________________________________________________________ -->
3582<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3583Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3584
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3585<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3586
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3587<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3588<pre>
3589 &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]3590</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3591
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3592<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3593<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3594 a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3595
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3596<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3597<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3598 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3599 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3600
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3601<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3602<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3603 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3604 is (statically or dynamically) negative or equal to or larger than the number
3605 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3606 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3607 shift amount in <tt>op2</tt>.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3608
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3609<h5>Example:</h5>
3610<pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3611 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3612 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3613 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3614 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3615 &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]3616</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3617
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3618</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3619
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3620<!-- _______________________________________________________________________ -->
3621<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3622Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3623
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3624<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3625
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3626<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3627<pre>
3628 &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]3629</pre>
3630
3631<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3632<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3633 operand shifted to the right a specified number of bits with zero fill.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3634
3635<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3636<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3637 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3638 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3639
3640<h5>Semantics:</h5>
3641<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3642 significant bits of the result will be filled with zero bits after the shift.
3643 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3644 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3645 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3646 shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3647
3648<h5>Example:</h5>
3649<pre>
3650 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3651 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3652 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3653 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3654 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3655 &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]3656</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3657
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3658</div>
3659
3660<!-- _______________________________________________________________________ -->
3661<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3662Instruction</a> </div>
3663<div class="doc_text">
3664
3665<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3666<pre>
3667 &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]3668</pre>
3669
3670<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3671<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3672 operand shifted to the right a specified number of bits with sign
3673 extension.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3674
3675<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3676<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3677 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3678 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3679
3680<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3681<p>This instruction always performs an arithmetic shift right operation, The
3682 most significant bits of the result will be filled with the sign bit
3683 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3684 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3685 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3686 the corresponding shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3687
3688<h5>Example:</h5>
3689<pre>
3690 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3691 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3692 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3693 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3694 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3695 &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]3696</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3697
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3698</div>
3699
3700<!-- _______________________________________________________________________ -->
3701<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3702Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3703
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3704<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3705
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3706<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3707<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3708 &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]3709</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3710
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3711<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3712<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3713 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3714
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3715<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3716<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3717 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3718 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3719
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3720<h5>Semantics:</h5>
3721<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3722
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3723<table border="1" cellspacing="0" cellpadding="4">
3724 <tbody>
3725 <tr>
3726 <td>In0</td>
3727 <td>In1</td>
3728 <td>Out</td>
3729 </tr>
3730 <tr>
3731 <td>0</td>
3732 <td>0</td>
3733 <td>0</td>
3734 </tr>
3735 <tr>
3736 <td>0</td>
3737 <td>1</td>
3738 <td>0</td>
3739 </tr>
3740 <tr>
3741 <td>1</td>
3742 <td>0</td>
3743 <td>0</td>
3744 </tr>
3745 <tr>
3746 <td>1</td>
3747 <td>1</td>
3748 <td>1</td>
3749 </tr>
3750 </tbody>
3751</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3752
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3753<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3754<pre>
3755 &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]3756 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3757 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
3758</pre>
3759</div>
3760<!-- _______________________________________________________________________ -->
3761<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3762
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3763<div class="doc_text">
3764
3765<h5>Syntax:</h5>
3766<pre>
3767 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3768</pre>
3769
3770<h5>Overview:</h5>
3771<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3772 two operands.</p>
3773
3774<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3775<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3776 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3777 values. Both arguments must have identical types.</p>
3778
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3779<h5>Semantics:</h5>
3780<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3781
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3782<table border="1" cellspacing="0" cellpadding="4">
3783 <tbody>
3784 <tr>
3785 <td>In0</td>
3786 <td>In1</td>
3787 <td>Out</td>
3788 </tr>
3789 <tr>
3790 <td>0</td>
3791 <td>0</td>
3792 <td>0</td>
3793 </tr>
3794 <tr>
3795 <td>0</td>
3796 <td>1</td>
3797 <td>1</td>
3798 </tr>
3799 <tr>
3800 <td>1</td>
3801 <td>0</td>
3802 <td>1</td>
3803 </tr>
3804 <tr>
3805 <td>1</td>
3806 <td>1</td>
3807 <td>1</td>
3808 </tr>
3809 </tbody>
3810</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3811
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3812<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3813<pre>
3814 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3815 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3816 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
3817</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3818
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3819</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3820
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3821<!-- _______________________________________________________________________ -->
3822<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3823Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3824
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3825<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3826
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3827<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3828<pre>
3829 &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]3830</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3831
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3832<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3833<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3834 its two operands. The <tt>xor</tt> is used to implement the "one's
3835 complement" operation, which is the "~" operator in C.</p>
3836
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3837<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3838<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3839 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3840 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3841
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3842<h5>Semantics:</h5>
3843<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3844
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3845<table border="1" cellspacing="0" cellpadding="4">
3846 <tbody>
3847 <tr>
3848 <td>In0</td>
3849 <td>In1</td>
3850 <td>Out</td>
3851 </tr>
3852 <tr>
3853 <td>0</td>
3854 <td>0</td>
3855 <td>0</td>
3856 </tr>
3857 <tr>
3858 <td>0</td>
3859 <td>1</td>
3860 <td>1</td>
3861 </tr>
3862 <tr>
3863 <td>1</td>
3864 <td>0</td>
3865 <td>1</td>
3866 </tr>
3867 <tr>
3868 <td>1</td>
3869 <td>1</td>
3870 <td>0</td>
3871 </tr>
3872 </tbody>
3873</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3874
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3875<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3876<pre>
3877 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3878 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3879 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3880 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
3881</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3882
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3883</div>
3884
3885<!-- ======================================================================= -->
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3886<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3887 <a name="vectorops">Vector Operations</a>
3888</div>
3889
3890<div class="doc_text">
3891
3892<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3893 target-independent manner. These instructions cover the element-access and
3894 vector-specific operations needed to process vectors effectively. While LLVM
3895 does directly support these vector operations, many sophisticated algorithms
3896 will want to use target-specific intrinsics to take full advantage of a
3897 specific target.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3898
3899</div>
3900
3901<!-- _______________________________________________________________________ -->
3902<div class="doc_subsubsection">
3903 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3904</div>
3905
3906<div class="doc_text">
3907
3908<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3909<pre>
3910 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
3911</pre>
3912
3913<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3914<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3915 from a vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3916
3917
3918<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3919<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3920 of <a href="#t_vector">vector</a> type. The second operand is an index
3921 indicating the position from which to extract the element. The index may be
3922 a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3923
3924<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3925<p>The result is a scalar of the same type as the element type of
3926 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3927 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3928 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3929
3930<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3931<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]3932 &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]3933</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3934
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3935</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3936
3937<!-- _______________________________________________________________________ -->
3938<div class="doc_subsubsection">
3939 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3940</div>
3941
3942<div class="doc_text">
3943
3944<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3945<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]3946 &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]3947</pre>
3948
3949<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3950<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
3951 vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3952
3953<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3954<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
3955 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
3956 whose type must equal the element type of the first operand. The third
3957 operand is an index indicating the position at which to insert the value.
3958 The index may be a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3959
3960<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3961<p>The result is a vector of the same type as <tt>val</tt>. Its element values
3962 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
3963 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3964 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3965
3966<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3967<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]3968 &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]3969</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3970
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3971</div>
3972
3973<!-- _______________________________________________________________________ -->
3974<div class="doc_subsubsection">
3975 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3976</div>
3977
3978<div class="doc_text">
3979
3980<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3981<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3982 &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]3983</pre>
3984
3985<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3986<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
3987 from two input vectors, returning a vector with the same element type as the
3988 input and length that is the same as the shuffle mask.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3989
3990<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3991<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3992 with types that match each other. The third argument is a shuffle mask whose
3993 element type is always 'i32'. The result of the instruction is a vector
3994 whose length is the same as the shuffle mask and whose element type is the
3995 same as the element type of the first two operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3996
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3997<p>The shuffle mask operand is required to be a constant vector with either
3998 constant integer or undef values.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3999
4000<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4001<p>The elements of the two input vectors are numbered from left to right across
4002 both of the vectors. The shuffle mask operand specifies, for each element of
4003 the result vector, which element of the two input vectors the result element
4004 gets. The element selector may be undef (meaning "don't care") and the
4005 second operand may be undef if performing a shuffle from only one vector.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4006
4007<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4008<pre>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4009 &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]4010 &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]4011 &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]4012 &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]4013 &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]4014 &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]4015 &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]4016 &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]4017</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4018
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4019</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4020
4021<!-- ======================================================================= -->
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4022<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4023 <a name="aggregateops">Aggregate Operations</a>
4024</div>
4025
4026<div class="doc_text">
4027
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4028<p>LLVM supports several instructions for working with
4029 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4030
4031</div>
4032
4033<!-- _______________________________________________________________________ -->
4034<div class="doc_subsubsection">
4035 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
4036</div>
4037
4038<div class="doc_text">
4039
4040<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4041<pre>
4042 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4043</pre>
4044
4045<h5>Overview:</h5>
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4046<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4047 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4048
4049<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4050<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4051 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4052 <a href="#t_array">array</a> type. The operands are constant indices to
4053 specify which value to extract in a similar manner as indices in a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4054 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4055
4056<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4057<p>The result is the value at the position in the aggregate specified by the
4058 index operands.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4059
4060<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4061<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]4062 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4063</pre>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4064
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4065</div>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4066
4067<!-- _______________________________________________________________________ -->
4068<div class="doc_subsubsection">
4069 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
4070</div>
4071
4072<div class="doc_text">
4073
4074<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4075<pre>
Jeffrey Yasskine05d7732010-01-11 19:19:26 +0000[diff] [blame]4076 &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]4077</pre>
4078
4079<h5>Overview:</h5>
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4080<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4081 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4082
4083<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4084<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4085 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4086 <a href="#t_array">array</a> type. The second operand is a first-class
4087 value to insert. The following operands are constant indices indicating
4088 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]4089 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
4090 value to insert must have the same type as the value identified by the
4091 indices.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4092
4093<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4094<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4095 that of <tt>val</tt> except that the value at the position specified by the
4096 indices is that of <tt>elt</tt>.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4097
4098<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4099<pre>
Jeffrey Yasskine05d7732010-01-11 19:19:26 +0000[diff] [blame]4100 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4101 %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]4102</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4103
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4104</div>
4105
4106
4107<!-- ======================================================================= -->
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4108<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4109 <a name="memoryops">Memory Access and Addressing Operations</a>
4110</div>
4111
4112<div class="doc_text">
4113
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4114<p>A key design point of an SSA-based representation is how it represents
4115 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]4116 very simple. This section describes how to read, write, and allocate
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4117 memory in LLVM.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4118
4119</div>
4120
4121<!-- _______________________________________________________________________ -->
4122<div class="doc_subsubsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4123 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4124</div>
4125
4126<div class="doc_text">
4127
4128<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4129<pre>
4130 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
4131</pre>
4132
4133<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4134<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4135 currently executing function, to be automatically released when this function
4136 returns to its caller. The object is always allocated in the generic address
4137 space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4138
4139<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4140<p>The '<tt>alloca</tt>' instruction
4141 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4142 runtime stack, returning a pointer of the appropriate type to the program.
4143 If "NumElements" is specified, it is the number of elements allocated,
4144 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4145 specified, the value result of the allocation is guaranteed to be aligned to
4146 at least that boundary. If not specified, or if zero, the target can choose
4147 to align the allocation on any convenient boundary compatible with the
4148 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4149
4150<p>'<tt>type</tt>' may be any sized type.</p>
4151
4152<h5>Semantics:</h5>
Bill Wendling2a454572009-05-08 20:49:29 +0000[diff] [blame]4153<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4154 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4155 memory is automatically released when the function returns. The
4156 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4157 variables that must have an address available. When the function returns
4158 (either with the <tt><a href="#i_ret">ret</a></tt>
4159 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4160 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4161
4162<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4163<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]4164 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4165 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4166 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4167 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4168</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4169
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4170</div>
4171
4172<!-- _______________________________________________________________________ -->
4173<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4174Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4175
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4176<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4177
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4178<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4179<pre>
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4180 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4181 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4182 !&lt;index&gt; = !{ i32 1 }
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4183</pre>
4184
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4185<h5>Overview:</h5>
4186<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4187
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4188<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4189<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4190 from which to load. The pointer must point to
4191 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4192 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
4193 number or order of execution of this <tt>load</tt> with other
4194 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4195 instructions.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4196
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4197<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4198 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]4199 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4200 alignment for the target. It is the responsibility of the code emitter to
4201 ensure that the alignment information is correct. Overestimating the
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4202 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4203 produce less efficient code. An alignment of 1 is always safe.</p>
4204
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4205<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4206 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]4207 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4208 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4209 and code generator that this load is not expected to be reused in the cache.
4210 The code generator may select special instructions to save cache bandwidth,
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]4211 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4212
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4213<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4214<p>The location of memory pointed to is loaded. If the value being loaded is of
4215 scalar type then the number of bytes read does not exceed the minimum number
4216 of bytes needed to hold all bits of the type. For example, loading an
4217 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4218 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4219 is undefined if the value was not originally written using a store of the
4220 same type.</p>
4221
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4222<h5>Examples:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4223<pre>
4224 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4225 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4226 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
4227</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4228
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4229</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4230
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4231<!-- _______________________________________________________________________ -->
4232<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4233Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4234
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4235<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4236
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4237<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4238<pre>
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4239 store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !<index>] <i>; yields {void}</i>
4240 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]4241</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4242
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4243<h5>Overview:</h5>
4244<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4245
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4246<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4247<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4248 and an address at which to store it. The type of the
4249 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4250 the <a href="#t_firstclass">first class</a> type of the
4251 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked
4252 as <tt>volatile</tt>, then the optimizer is not allowed to modify the number
4253 or order of execution of this <tt>store</tt> with other
4254 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
4255 instructions.</p>
4256
4257<p>The optional constant "align" argument specifies the alignment of the
4258 operation (that is, the alignment of the memory address). A value of 0 or an
4259 omitted "align" argument means that the operation has the preferential
4260 alignment for the target. It is the responsibility of the code emitter to
4261 ensure that the alignment information is correct. Overestimating the
4262 alignment results in an undefined behavior. Underestimating the alignment may
4263 produce less efficient code. An alignment of 1 is always safe.</p>
4264
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4265<p>The optional !nontemporal metadata must reference a single metatadata
4266 name <index> corresponding to a metadata node with one i32 entry of
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]4267 value 1. The existence of the !nontemporal metatadata on the
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4268 instruction tells the optimizer and code generator that this load is
4269 not expected to be reused in the cache. The code generator may
4270 select special instructions to save cache bandwidth, such as the
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]4271 MOVNT instruction on x86.</p>
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4272
4273
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4274<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4275<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4276 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4277 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4278 does not exceed the minimum number of bytes needed to hold all bits of the
4279 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4280 writing a value of a type like <tt>i20</tt> with a size that is not an
4281 integral number of bytes, it is unspecified what happens to the extra bits
4282 that do not belong to the type, but they will typically be overwritten.</p>
4283
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4284<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4285<pre>
4286 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]4287 store i32 3, i32* %ptr <i>; yields {void}</i>
4288 %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]4289</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4290
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4291</div>
4292
4293<!-- _______________________________________________________________________ -->
4294<div class="doc_subsubsection">
4295 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4296</div>
4297
4298<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4299
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4300<h5>Syntax:</h5>
4301<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4302 &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]4303 &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]4304</pre>
4305
4306<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4307<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4308 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4309 It performs address calculation only and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4310
4311<h5>Arguments:</h5>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4312<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnere92fc832009-07-29 06:44:13 +0000[diff] [blame]4313 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4314 elements of the aggregate object are indexed. The interpretation of each
4315 index is dependent on the type being indexed into. The first index always
4316 indexes the pointer value given as the first argument, the second index
4317 indexes a value of the type pointed to (not necessarily the value directly
4318 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4319 indexed into must be a pointer value, subsequent types can be arrays,
4320 vectors, structs and unions. Note that subsequent types being indexed into
4321 can never be pointers, since that would require loading the pointer before
4322 continuing calculation.</p>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4323
4324<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]4325 When indexing into a (optionally packed) structure or union, only <tt>i32</tt>
4326 integer <b>constants</b> are allowed. When indexing into an array, pointer
4327 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]4328 constant.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4329
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4330<p>For example, let's consider a C code fragment and how it gets compiled to
4331 LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4332
4333<div class="doc_code">
4334<pre>
4335struct RT {
4336 char A;
4337 int B[10][20];
4338 char C;
4339};
4340struct ST {
4341 int X;
4342 double Y;
4343 struct RT Z;
4344};
4345
4346int *foo(struct ST *s) {
4347 return &amp;s[1].Z.B[5][13];
4348}
4349</pre>
4350</div>
4351
4352<p>The LLVM code generated by the GCC frontend is:</p>
4353
4354<div class="doc_code">
4355<pre>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]4356%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4357%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4358
Dan Gohman47360842009-07-25 02:23:48 +0000[diff] [blame]4359define i32* @foo(%ST* %s) {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4360entry:
4361 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4362 ret i32* %reg
4363}
4364</pre>
4365</div>
4366
4367<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4368<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]4369 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4370 }</tt>' type, a structure. The second index indexes into the third element
4371 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4372 i8 }</tt>' type, another structure. The third index indexes into the second
4373 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4374 array. The two dimensions of the array are subscripted into, yielding an
4375 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4376 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4377
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4378<p>Note that it is perfectly legal to index partially through a structure,
4379 returning a pointer to an inner element. Because of this, the LLVM code for
4380 the given testcase is equivalent to:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4381
4382<pre>
Dan Gohman47360842009-07-25 02:23:48 +0000[diff] [blame]4383 define i32* @foo(%ST* %s) {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4384 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
4385 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4386 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
4387 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4388 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4389 ret i32* %t5
4390 }
4391</pre>
4392
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4393<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohmanf7263862010-04-23 15:23:32 +0000[diff] [blame^]4394 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
4395 base pointer is not an <i>in bounds</i> address of an allocated object,
4396 or if any of the addresses that would be formed by successive addition of
4397 the offsets implied by the indices to the base address with infinitely
4398 precise arithmetic are not an <i>in bounds</i> address of that allocated
4399 object. The <i>in bounds</i> addresses for an allocated object are all
4400 the addresses that point into the object, plus the address one byte past
4401 the end.</p>
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4402
4403<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4404 the base address with silently-wrapping two's complement arithmetic, and
4405 the result value of the <tt>getelementptr</tt> may be outside the object
4406 pointed to by the base pointer. The result value may not necessarily be
4407 used to access memory though, even if it happens to point into allocated
4408 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4409 section for more information.</p>
4410
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4411<p>The getelementptr instruction is often confusing. For some more insight into
4412 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4413
4414<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4415<pre>
4416 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4417 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4418 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4419 %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]4420 <i>; yields i8*:eptr</i>
4421 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta4f9a0dc2009-04-25 07:27:44 +0000[diff] [blame]4422 <i>; yields i32*:iptr</i>
Sanjiv Gupta1e46c582009-04-24 16:38:13 +0000[diff] [blame]4423 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4424</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4425
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4426</div>
4427
4428<!-- ======================================================================= -->
4429<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
4430</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4431
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4432<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4433
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4434<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4435 which all take a single operand and a type. They perform various bit
4436 conversions on the operand.</p>
4437
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4438</div>
4439
4440<!-- _______________________________________________________________________ -->
4441<div class="doc_subsubsection">
4442 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4443</div>
4444<div class="doc_text">
4445
4446<h5>Syntax:</h5>
4447<pre>
4448 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4449</pre>
4450
4451<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4452<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4453 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4454
4455<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4456<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4457 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4458 size and type of the result, which must be
4459 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4460 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4461 allowed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4462
4463<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4464<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4465 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4466 source size must be larger than the destination size, <tt>trunc</tt> cannot
4467 be a <i>no-op cast</i>. It will always truncate bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4468
4469<h5>Example:</h5>
4470<pre>
4471 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
4472 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4473 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4474</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4475
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4476</div>
4477
4478<!-- _______________________________________________________________________ -->
4479<div class="doc_subsubsection">
4480 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4481</div>
4482<div class="doc_text">
4483
4484<h5>Syntax:</h5>
4485<pre>
4486 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4487</pre>
4488
4489<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4490<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4491 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4492
4493
4494<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4495<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]4496 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4497 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]4498 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4499 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4500
4501<h5>Semantics:</h5>
4502<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]4503 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4504
4505<p>When zero extending from i1, the result will always be either 0 or 1.</p>
4506
4507<h5>Example:</h5>
4508<pre>
4509 %X = zext i32 257 to i64 <i>; yields i64:257</i>
4510 %Y = zext i1 true to i32 <i>; yields i32:1</i>
4511</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4512
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4513</div>
4514
4515<!-- _______________________________________________________________________ -->
4516<div class="doc_subsubsection">
4517 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4518</div>
4519<div class="doc_text">
4520
4521<h5>Syntax:</h5>
4522<pre>
4523 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4524</pre>
4525
4526<h5>Overview:</h5>
4527<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4528
4529<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4530<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]4531 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4532 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]4533 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4534 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4535
4536<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4537<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4538 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4539 of the type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4540
4541<p>When sign extending from i1, the extension always results in -1 or 0.</p>
4542
4543<h5>Example:</h5>
4544<pre>
4545 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
4546 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
4547</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4548
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4549</div>
4550
4551<!-- _______________________________________________________________________ -->
4552<div class="doc_subsubsection">
4553 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4554</div>
4555
4556<div class="doc_text">
4557
4558<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4559<pre>
4560 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4561</pre>
4562
4563<h5>Overview:</h5>
4564<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4565 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4566
4567<h5>Arguments:</h5>
4568<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4569 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4570 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]4571 <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]4572 <i>no-op cast</i>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4573
4574<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4575<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4576 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4577 <a href="#t_floating">floating point</a> type. If the value cannot fit
4578 within the destination type, <tt>ty2</tt>, then the results are
4579 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4580
4581<h5>Example:</h5>
4582<pre>
4583 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4584 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4585</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4586
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4587</div>
4588
4589<!-- _______________________________________________________________________ -->
4590<div class="doc_subsubsection">
4591 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4592</div>
4593<div class="doc_text">
4594
4595<h5>Syntax:</h5>
4596<pre>
4597 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4598</pre>
4599
4600<h5>Overview:</h5>
4601<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]4602 floating point value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4603
4604<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4605<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4606 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4607 a <a href="#t_floating">floating point</a> type to cast it to. The source
4608 type must be smaller than the destination type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4609
4610<h5>Semantics:</h5>
4611<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4612 <a href="#t_floating">floating point</a> type to a larger
4613 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4614 used to make a <i>no-op cast</i> because it always changes bits. Use
4615 <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]4616
4617<h5>Example:</h5>
4618<pre>
4619 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4620 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4621</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4622
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4623</div>
4624
4625<!-- _______________________________________________________________________ -->
4626<div class="doc_subsubsection">
4627 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
4628</div>
4629<div class="doc_text">
4630
4631<h5>Syntax:</h5>
4632<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4633 &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]4634</pre>
4635
4636<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4637<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4638 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4639
4640<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4641<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4642 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4643 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4644 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4645 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4646
4647<h5>Semantics:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4648<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4649 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4650 towards zero) unsigned integer value. If the value cannot fit
4651 in <tt>ty2</tt>, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4652
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4653<h5>Example:</h5>
4654<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4655 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4656 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4657 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4658</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4659
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4660</div>
4661
4662<!-- _______________________________________________________________________ -->
4663<div class="doc_subsubsection">
4664 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
4665</div>
4666<div class="doc_text">
4667
4668<h5>Syntax:</h5>
4669<pre>
4670 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4671</pre>
4672
4673<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4674<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4675 <a href="#t_floating">floating point</a> <tt>value</tt> to
4676 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4677
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4678<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4679<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4680 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4681 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4682 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4683 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4684
4685<h5>Semantics:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4686<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4687 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4688 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4689 the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4690
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4691<h5>Example:</h5>
4692<pre>
4693 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4694 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4695 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4696</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4697
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4698</div>
4699
4700<!-- _______________________________________________________________________ -->
4701<div class="doc_subsubsection">
4702 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
4703</div>
4704<div class="doc_text">
4705
4706<h5>Syntax:</h5>
4707<pre>
4708 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4709</pre>
4710
4711<h5>Overview:</h5>
4712<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4713 integer and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4714
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4715<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4716<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]4717 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4718 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4719 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4720 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4721
4722<h5>Semantics:</h5>
4723<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4724 integer quantity and converts it to the corresponding floating point
4725 value. If the value cannot fit in the floating point value, the results are
4726 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4727
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4728<h5>Example:</h5>
4729<pre>
4730 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4731 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4732</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4733
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4734</div>
4735
4736<!-- _______________________________________________________________________ -->
4737<div class="doc_subsubsection">
4738 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
4739</div>
4740<div class="doc_text">
4741
4742<h5>Syntax:</h5>
4743<pre>
4744 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4745</pre>
4746
4747<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4748<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4749 and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4750
4751<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4752<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]4753 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4754 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4755 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4756 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4757
4758<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4759<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4760 quantity and converts it to the corresponding floating point value. If the
4761 value cannot fit in the floating point value, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4762
4763<h5>Example:</h5>
4764<pre>
4765 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4766 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4767</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4768
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4769</div>
4770
4771<!-- _______________________________________________________________________ -->
4772<div class="doc_subsubsection">
4773 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4774</div>
4775<div class="doc_text">
4776
4777<h5>Syntax:</h5>
4778<pre>
4779 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4780</pre>
4781
4782<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4783<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4784 the integer type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4785
4786<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4787<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4788 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4789 <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]4790
4791<h5>Semantics:</h5>
4792<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4793 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4794 truncating or zero extending that value to the size of the integer type. If
4795 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4796 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4797 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4798 change.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4799
4800<h5>Example:</h5>
4801<pre>
4802 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4803 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
4804</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4805
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4806</div>
4807
4808<!-- _______________________________________________________________________ -->
4809<div class="doc_subsubsection">
4810 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4811</div>
4812<div class="doc_text">
4813
4814<h5>Syntax:</h5>
4815<pre>
4816 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4817</pre>
4818
4819<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4820<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4821 pointer type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4822
4823<h5>Arguments:</h5>
4824<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4825 value to cast, and a type to cast it to, which must be a
4826 <a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4827
4828<h5>Semantics:</h5>
4829<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4830 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4831 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4832 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4833 than the size of a pointer then a zero extension is done. If they are the
4834 same size, nothing is done (<i>no-op cast</i>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4835
4836<h5>Example:</h5>
4837<pre>
4838 %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]4839 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4840 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4841</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4842
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4843</div>
4844
4845<!-- _______________________________________________________________________ -->
4846<div class="doc_subsubsection">
4847 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
4848</div>
4849<div class="doc_text">
4850
4851<h5>Syntax:</h5>
4852<pre>
4853 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4854</pre>
4855
4856<h5>Overview:</h5>
4857<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4858 <tt>ty2</tt> without changing any bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4859
4860<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4861<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4862 non-aggregate first class value, and a type to cast it to, which must also be
4863 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4864 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4865 identical. If the source type is a pointer, the destination type must also be
4866 a pointer. This instruction supports bitwise conversion of vectors to
4867 integers and to vectors of other types (as long as they have the same
4868 size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4869
4870<h5>Semantics:</h5>
4871<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4872 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4873 this conversion. The conversion is done as if the <tt>value</tt> had been
4874 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4875 be converted to other pointer types with this instruction. To convert
4876 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4877 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4878
4879<h5>Example:</h5>
4880<pre>
4881 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
4882 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4883 %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]4884</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4885
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4886</div>
4887
4888<!-- ======================================================================= -->
4889<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4890
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4891<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4892
4893<p>The instructions in this category are the "miscellaneous" instructions, which
4894 defy better classification.</p>
4895
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4896</div>
4897
4898<!-- _______________________________________________________________________ -->
4899<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4900</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4901
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4902<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4903
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4904<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4905<pre>
4906 &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]4907</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4908
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4909<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4910<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4911 boolean values based on comparison of its two integer, integer vector, or
4912 pointer operands.</p>
4913
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4914<h5>Arguments:</h5>
4915<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4916 the condition code indicating the kind of comparison to perform. It is not a
4917 value, just a keyword. The possible condition code are:</p>
4918
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4919<ol>
4920 <li><tt>eq</tt>: equal</li>
4921 <li><tt>ne</tt>: not equal </li>
4922 <li><tt>ugt</tt>: unsigned greater than</li>
4923 <li><tt>uge</tt>: unsigned greater or equal</li>
4924 <li><tt>ult</tt>: unsigned less than</li>
4925 <li><tt>ule</tt>: unsigned less or equal</li>
4926 <li><tt>sgt</tt>: signed greater than</li>
4927 <li><tt>sge</tt>: signed greater or equal</li>
4928 <li><tt>slt</tt>: signed less than</li>
4929 <li><tt>sle</tt>: signed less or equal</li>
4930</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4931
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4932<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4933 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
4934 typed. They must also be identical types.</p>
4935
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4936<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4937<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
4938 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]4939 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]4940 result, as follows:</p>
4941
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4942<ol>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4943 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4944 <tt>false</tt> otherwise. No sign interpretation is necessary or
4945 performed.</li>
4946
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4947 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4948 <tt>false</tt> otherwise. No sign interpretation is necessary or
4949 performed.</li>
4950
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4951 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4952 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4953
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4954 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4955 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4956 to <tt>op2</tt>.</li>
4957
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4958 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4959 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4960
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4961 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4962 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4963
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4964 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4965 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4966
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4967 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4968 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4969 to <tt>op2</tt>.</li>
4970
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4971 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4972 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4973
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4974 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4975 <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]4976</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4977
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4978<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4979 values are compared as if they were integers.</p>
4980
4981<p>If the operands are integer vectors, then they are compared element by
4982 element. The result is an <tt>i1</tt> vector with the same number of elements
4983 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4984
4985<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4986<pre>
4987 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4988 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4989 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4990 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4991 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4992 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
4993</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4994
4995<p>Note that the code generator does not yet support vector types with
4996 the <tt>icmp</tt> instruction.</p>
4997
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4998</div>
4999
5000<!-- _______________________________________________________________________ -->
5001<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5002</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5003
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5004<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5005
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5006<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5007<pre>
5008 &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]5009</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5010
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5011<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5012<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5013 values based on comparison of its operands.</p>
5014
5015<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]5016(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5017
5018<p>If the operands are floating point vectors, then the result type is a vector
5019 of boolean with the same number of elements as the operands being
5020 compared.</p>
5021
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5022<h5>Arguments:</h5>
5023<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5024 the condition code indicating the kind of comparison to perform. It is not a
5025 value, just a keyword. The possible condition code are:</p>
5026
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5027<ol>
5028 <li><tt>false</tt>: no comparison, always returns false</li>
5029 <li><tt>oeq</tt>: ordered and equal</li>
5030 <li><tt>ogt</tt>: ordered and greater than </li>
5031 <li><tt>oge</tt>: ordered and greater than or equal</li>
5032 <li><tt>olt</tt>: ordered and less than </li>
5033 <li><tt>ole</tt>: ordered and less than or equal</li>
5034 <li><tt>one</tt>: ordered and not equal</li>
5035 <li><tt>ord</tt>: ordered (no nans)</li>
5036 <li><tt>ueq</tt>: unordered or equal</li>
5037 <li><tt>ugt</tt>: unordered or greater than </li>
5038 <li><tt>uge</tt>: unordered or greater than or equal</li>
5039 <li><tt>ult</tt>: unordered or less than </li>
5040 <li><tt>ule</tt>: unordered or less than or equal</li>
5041 <li><tt>une</tt>: unordered or not equal</li>
5042 <li><tt>uno</tt>: unordered (either nans)</li>
5043 <li><tt>true</tt>: no comparison, always returns true</li>
5044</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5045
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5046<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5047 <i>unordered</i> means that either operand may be a QNAN.</p>
5048
5049<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5050 a <a href="#t_floating">floating point</a> type or
5051 a <a href="#t_vector">vector</a> of floating point type. They must have
5052 identical types.</p>
5053
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5054<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]5055<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5056 according to the condition code given as <tt>cond</tt>. If the operands are
5057 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]5058 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5059 follows:</p>
5060
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5061<ol>
5062 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5063
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5064 <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]5065 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5066
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5067 <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]5068 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5069
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5070 <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]5071 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5072
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5073 <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]5074 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5075
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5076 <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]5077 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5078
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5079 <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]5080 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5081
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5082 <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]5083
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5084 <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]5085 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5086
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5087 <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]5088 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5089
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5090 <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]5091 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5092
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5093 <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]5094 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5095
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5096 <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]5097 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5098
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5099 <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]5100 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5101
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5102 <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]5103
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5104 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5105</ol>
5106
5107<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5108<pre>
5109 &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]5110 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5111 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5112 &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]5113</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]5114
5115<p>Note that the code generator does not yet support vector types with
5116 the <tt>fcmp</tt> instruction.</p>
5117
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5118</div>
5119
5120<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]5121<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5122 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5123</div>
5124
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5125<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5126
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5127<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5128<pre>
5129 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5130</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5131
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5132<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5133<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5134 SSA graph representing the function.</p>
5135
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5136<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5137<p>The type of the incoming values is specified with the first type field. After
5138 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5139 one pair for each predecessor basic block of the current block. Only values
5140 of <a href="#t_firstclass">first class</a> type may be used as the value
5141 arguments to the PHI node. Only labels may be used as the label
5142 arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5143
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5144<p>There must be no non-phi instructions between the start of a basic block and
5145 the PHI instructions: i.e. PHI instructions must be first in a basic
5146 block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5147
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5148<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5149 occur on the edge from the corresponding predecessor block to the current
5150 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5151 value on the same edge).</p>
Jay Foad8e2fd2c2009-06-03 10:20:10 +0000[diff] [blame]5152
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5153<h5>Semantics:</h5>
5154<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5155 specified by the pair corresponding to the predecessor basic block that
5156 executed just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5157
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5158<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5159<pre>
5160Loop: ; Infinite loop that counts from 0 on up...
5161 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5162 %nextindvar = add i32 %indvar, 1
5163 br label %Loop
5164</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5165
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5166</div>
5167
5168<!-- _______________________________________________________________________ -->
5169<div class="doc_subsubsection">
5170 <a name="i_select">'<tt>select</tt>' Instruction</a>
5171</div>
5172
5173<div class="doc_text">
5174
5175<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5176<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]5177 &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>
5178
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5179 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5180</pre>
5181
5182<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5183<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5184 condition, without branching.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5185
5186
5187<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5188<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5189 values indicating the condition, and two values of the
5190 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5191 vectors and the condition is a scalar, then entire vectors are selected, not
5192 individual elements.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5193
5194<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5195<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5196 first value argument; otherwise, it returns the second value argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5197
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5198<p>If the condition is a vector of i1, then the value arguments must be vectors
5199 of the same size, and the selection is done element by element.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5200
5201<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5202<pre>
5203 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
5204</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]5205
5206<p>Note that the code generator does not yet support conditions
5207 with vector type.</p>
5208
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5209</div>
5210
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5211<!-- _______________________________________________________________________ -->
5212<div class="doc_subsubsection">
5213 <a name="i_call">'<tt>call</tt>' Instruction</a>
5214</div>
5215
5216<div class="doc_text">
5217
5218<h5>Syntax:</h5>
5219<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]5220 &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]5221</pre>
5222
5223<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5224<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
5225
5226<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5227<p>This instruction requires several arguments:</p>
5228
5229<ol>
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]5230 <li>The optional "tail" marker indicates that the callee function does not
5231 access any allocas or varargs in the caller. Note that calls may be
5232 marked "tail" even if they do not occur before
5233 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5234 present, the function call is eligible for tail call optimization,
5235 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Chengcc7495c2010-03-08 21:05:02 +0000[diff] [blame]5236 optimized into a jump</a>. The code generator may optimize calls marked
5237 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5238 sibling call optimization</a> when the caller and callee have
5239 matching signatures, or 2) forced tail call optimization when the
5240 following extra requirements are met:
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]5241 <ul>
5242 <li>Caller and callee both have the calling
5243 convention <tt>fastcc</tt>.</li>
5244 <li>The call is in tail position (ret immediately follows call and ret
5245 uses value of call or is void).</li>
5246 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohman1be84f02010-03-02 01:08:11 +0000[diff] [blame]5247 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]5248 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5249 constraints are met.</a></li>
5250 </ul>
5251 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5252
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5253 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5254 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]5255 defaults to using C calling conventions. The calling convention of the
5256 call must match the calling convention of the target function, or else the
5257 behavior is undefined.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5258
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5259 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5260 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5261 '<tt>inreg</tt>' attributes are valid here.</li>
5262
5263 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5264 type of the return value. Functions that return no value are marked
5265 <tt><a href="#t_void">void</a></tt>.</li>
5266
5267 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5268 being invoked. The argument types must match the types implied by this
5269 signature. This type can be omitted if the function is not varargs and if
5270 the function type does not return a pointer to a function.</li>
5271
5272 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5273 be invoked. In most cases, this is a direct function invocation, but
5274 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5275 to function value.</li>
5276
5277 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner553fb1e2010-03-02 06:36:51 +0000[diff] [blame]5278 signature argument types and parameter attributes. All arguments must be
5279 of <a href="#t_firstclass">first class</a> type. If the function
5280 signature indicates the function accepts a variable number of arguments,
5281 the extra arguments can be specified.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5282
5283 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5284 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5285 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5286</ol>
5287
5288<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5289<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5290 a specified function, with its incoming arguments bound to the specified
5291 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5292 function, control flow continues with the instruction after the function
5293 call, and the return value of the function is bound to the result
5294 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5295
5296<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5297<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]5298 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]5299 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
5300 %X = tail call i32 @foo() <i>; yields i32</i>
5301 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5302 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]5303
5304 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5305 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]5306 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5307 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +0000[diff] [blame]5308 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +0000[diff] [blame]5309 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5310</pre>
5311
Dale Johannesen9fcf4a92009-09-24 18:38:21 +0000[diff] [blame]5312<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen4730cd32009-09-25 17:04:42 +0000[diff] [blame]5313standard C99 library as being the C99 library functions, and may perform
5314optimizations or generate code for them under that assumption. This is
5315something we'd like to change in the future to provide better support for
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]5316freestanding environments and non-C-based languages.</p>
Dale Johannesen9fcf4a92009-09-24 18:38:21 +0000[diff] [blame]5317
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5318</div>
5319
5320<!-- _______________________________________________________________________ -->
5321<div class="doc_subsubsection">
5322 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
5323</div>
5324
5325<div class="doc_text">
5326
5327<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5328<pre>
5329 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
5330</pre>
5331
5332<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5333<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5334 the "variable argument" area of a function call. It is used to implement the
5335 <tt>va_arg</tt> macro in C.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5336
5337<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5338<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5339 argument. It returns a value of the specified argument type and increments
5340 the <tt>va_list</tt> to point to the next argument. The actual type
5341 of <tt>va_list</tt> is target specific.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5342
5343<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5344<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5345 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5346 to the next argument. For more information, see the variable argument
5347 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5348
5349<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]5350 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5351 function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5352
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5353<p><tt>va_arg</tt> is an LLVM instruction instead of
5354 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5355 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5356
5357<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5358<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5359
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5360<p>Note that the code generator does not yet fully support va_arg on many
5361 targets. Also, it does not currently support va_arg with aggregate types on
5362 any target.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]5363
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5364</div>
5365
5366<!-- *********************************************************************** -->
5367<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5368<!-- *********************************************************************** -->
5369
5370<div class="doc_text">
5371
5372<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5373 well known names and semantics and are required to follow certain
5374 restrictions. Overall, these intrinsics represent an extension mechanism for
5375 the LLVM language that does not require changing all of the transformations
5376 in LLVM when adding to the language (or the bitcode reader/writer, the
5377 parser, etc...).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5378
5379<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5380 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5381 begin with this prefix. Intrinsic functions must always be external
5382 functions: you cannot define the body of intrinsic functions. Intrinsic
5383 functions may only be used in call or invoke instructions: it is illegal to
5384 take the address of an intrinsic function. Additionally, because intrinsic
5385 functions are part of the LLVM language, it is required if any are added that
5386 they be documented here.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5387
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5388<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5389 family of functions that perform the same operation but on different data
5390 types. Because LLVM can represent over 8 million different integer types,
5391 overloading is used commonly to allow an intrinsic function to operate on any
5392 integer type. One or more of the argument types or the result type can be
5393 overloaded to accept any integer type. Argument types may also be defined as
5394 exactly matching a previous argument's type or the result type. This allows
5395 an intrinsic function which accepts multiple arguments, but needs all of them
5396 to be of the same type, to only be overloaded with respect to a single
5397 argument or the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5398
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5399<p>Overloaded intrinsics will have the names of its overloaded argument types
5400 encoded into its function name, each preceded by a period. Only those types
5401 which are overloaded result in a name suffix. Arguments whose type is matched
5402 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5403 can take an integer of any width and returns an integer of exactly the same
5404 integer width. This leads to a family of functions such as
5405 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5406 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5407 suffix is required. Because the argument's type is matched against the return
5408 type, it does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5409
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5410<p>To learn how to add an intrinsic function, please see the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5411 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5412
5413</div>
5414
5415<!-- ======================================================================= -->
5416<div class="doc_subsection">
5417 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5418</div>
5419
5420<div class="doc_text">
5421
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5422<p>Variable argument support is defined in LLVM with
5423 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5424 intrinsic functions. These functions are related to the similarly named
5425 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5426
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5427<p>All of these functions operate on arguments that use a target-specific value
5428 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5429 not define what this type is, so all transformations should be prepared to
5430 handle these functions regardless of the type used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5431
5432<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]5433 instruction and the variable argument handling intrinsic functions are
5434 used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5435
5436<div class="doc_code">
5437<pre>
5438define i32 @test(i32 %X, ...) {
5439 ; Initialize variable argument processing
5440 %ap = alloca i8*
5441 %ap2 = bitcast i8** %ap to i8*
5442 call void @llvm.va_start(i8* %ap2)
5443
5444 ; Read a single integer argument
5445 %tmp = va_arg i8** %ap, i32
5446
5447 ; Demonstrate usage of llvm.va_copy and llvm.va_end
5448 %aq = alloca i8*
5449 %aq2 = bitcast i8** %aq to i8*
5450 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
5451 call void @llvm.va_end(i8* %aq2)
5452
5453 ; Stop processing of arguments.
5454 call void @llvm.va_end(i8* %ap2)
5455 ret i32 %tmp
5456}
5457
5458declare void @llvm.va_start(i8*)
5459declare void @llvm.va_copy(i8*, i8*)
5460declare void @llvm.va_end(i8*)
5461</pre>
5462</div>
5463
5464</div>
5465
5466<!-- _______________________________________________________________________ -->
5467<div class="doc_subsubsection">
5468 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
5469</div>
5470
5471
5472<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5473
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5474<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5475<pre>
5476 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5477</pre>
5478
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5479<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5480<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5481 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]5482
5483<h5>Arguments:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5484<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]5485
5486<h5>Semantics:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5487<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]5488 macro available in C. In a target-dependent way, it initializes
5489 the <tt>va_list</tt> element to which the argument points, so that the next
5490 call to <tt>va_arg</tt> will produce the first variable argument passed to
5491 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5492 need to know the last argument of the function as the compiler can figure
5493 that out.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5494
5495</div>
5496
5497<!-- _______________________________________________________________________ -->
5498<div class="doc_subsubsection">
5499 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
5500</div>
5501
5502<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5503
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5504<h5>Syntax:</h5>
5505<pre>
5506 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5507</pre>
5508
5509<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5510<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5511 which has been initialized previously
5512 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5513 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5514
5515<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5516<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
5517
5518<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5519<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]5520 macro available in C. In a target-dependent way, it destroys
5521 the <tt>va_list</tt> element to which the argument points. Calls
5522 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5523 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5524 with calls to <tt>llvm.va_end</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5525
5526</div>
5527
5528<!-- _______________________________________________________________________ -->
5529<div class="doc_subsubsection">
5530 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
5531</div>
5532
5533<div class="doc_text">
5534
5535<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5536<pre>
5537 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
5538</pre>
5539
5540<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5541<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5542 from the source argument list to the destination argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5543
5544<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5545<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]5546 The second argument is a pointer to a <tt>va_list</tt> element to copy
5547 from.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5548
5549<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5550<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]5551 macro available in C. In a target-dependent way, it copies the
5552 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5553 element. This intrinsic is necessary because
5554 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5555 arbitrarily complex and require, for example, memory allocation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5556
5557</div>
5558
5559<!-- ======================================================================= -->
5560<div class="doc_subsection">
5561 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5562</div>
5563
5564<div class="doc_text">
5565
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5566<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5567Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5568intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5569roots on the stack</a>, as well as garbage collector implementations that
5570require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5571barriers. Front-ends for type-safe garbage collected languages should generate
5572these intrinsics to make use of the LLVM garbage collectors. For more details,
5573see <a href="GarbageCollection.html">Accurate Garbage Collection with
5574LLVM</a>.</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5575
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5576<p>The garbage collection intrinsics only operate on objects in the generic
5577 address space (address space zero).</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5578
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5579</div>
5580
5581<!-- _______________________________________________________________________ -->
5582<div class="doc_subsubsection">
5583 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
5584</div>
5585
5586<div class="doc_text">
5587
5588<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5589<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5590 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5591</pre>
5592
5593<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5594<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]5595 the code generator, and allows some metadata to be associated with it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5596
5597<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5598<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5599 root pointer. The second pointer (which must be either a constant or a
5600 global value address) contains the meta-data to be associated with the
5601 root.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5602
5603<h5>Semantics:</h5>
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]5604<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]5605 location. At compile-time, the code generator generates information to allow
5606 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5607 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5608 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5609
5610</div>
5611
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5612<!-- _______________________________________________________________________ -->
5613<div class="doc_subsubsection">
5614 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
5615</div>
5616
5617<div class="doc_text">
5618
5619<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5620<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5621 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5622</pre>
5623
5624<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5625<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5626 locations, allowing garbage collector implementations that require read
5627 barriers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5628
5629<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5630<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]5631 allocated from the garbage collector. The first object is a pointer to the
5632 start of the referenced object, if needed by the language runtime (otherwise
5633 null).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5634
5635<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5636<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5637 instruction, but may be replaced with substantially more complex code by the
5638 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5639 may only be used in a function which <a href="#gc">specifies a GC
5640 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5641
5642</div>
5643
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5644<!-- _______________________________________________________________________ -->
5645<div class="doc_subsubsection">
5646 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
5647</div>
5648
5649<div class="doc_text">
5650
5651<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5652<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5653 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5654</pre>
5655
5656<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5657<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5658 locations, allowing garbage collector implementations that require write
5659 barriers (such as generational or reference counting collectors).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5660
5661<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5662<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]5663 object to store it to, and the third is the address of the field of Obj to
5664 store to. If the runtime does not require a pointer to the object, Obj may
5665 be null.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5666
5667<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5668<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5669 instruction, but may be replaced with substantially more complex code by the
5670 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5671 may only be used in a function which <a href="#gc">specifies a GC
5672 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5673
5674</div>
5675
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5676<!-- ======================================================================= -->
5677<div class="doc_subsection">
5678 <a name="int_codegen">Code Generator Intrinsics</a>
5679</div>
5680
5681<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5682
5683<p>These intrinsics are provided by LLVM to expose special features that may
5684 only be implemented with code generator support.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5685
5686</div>
5687
5688<!-- _______________________________________________________________________ -->
5689<div class="doc_subsubsection">
5690 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
5691</div>
5692
5693<div class="doc_text">
5694
5695<h5>Syntax:</h5>
5696<pre>
5697 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
5698</pre>
5699
5700<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5701<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5702 target-specific value indicating the return address of the current function
5703 or one of its callers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5704
5705<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5706<p>The argument to this intrinsic indicates which function to return the address
5707 for. Zero indicates the calling function, one indicates its caller, etc.
5708 The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5709
5710<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5711<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5712 indicating the return address of the specified call frame, or zero if it
5713 cannot be identified. The value returned by this intrinsic is likely to be
5714 incorrect or 0 for arguments other than zero, so it should only be used for
5715 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5716
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5717<p>Note that calling this intrinsic does not prevent function inlining or other
5718 aggressive transformations, so the value returned may not be that of the
5719 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5720
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5721</div>
5722
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5723<!-- _______________________________________________________________________ -->
5724<div class="doc_subsubsection">
5725 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
5726</div>
5727
5728<div class="doc_text">
5729
5730<h5>Syntax:</h5>
5731<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5732 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5733</pre>
5734
5735<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5736<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5737 target-specific frame pointer value for the specified stack frame.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5738
5739<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5740<p>The argument to this intrinsic indicates which function to return the frame
5741 pointer for. Zero indicates the calling function, one indicates its caller,
5742 etc. The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5743
5744<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5745<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5746 indicating the frame address of the specified call frame, or zero if it
5747 cannot be identified. The value returned by this intrinsic is likely to be
5748 incorrect or 0 for arguments other than zero, so it should only be used for
5749 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5750
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5751<p>Note that calling this intrinsic does not prevent function inlining or other
5752 aggressive transformations, so the value returned may not be that of the
5753 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5754
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5755</div>
5756
5757<!-- _______________________________________________________________________ -->
5758<div class="doc_subsubsection">
5759 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
5760</div>
5761
5762<div class="doc_text">
5763
5764<h5>Syntax:</h5>
5765<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5766 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5767</pre>
5768
5769<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5770<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5771 of the function stack, for use
5772 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5773 useful for implementing language features like scoped automatic variable
5774 sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5775
5776<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5777<p>This intrinsic returns a opaque pointer value that can be passed
5778 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5779 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5780 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5781 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5782 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5783 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5784
5785</div>
5786
5787<!-- _______________________________________________________________________ -->
5788<div class="doc_subsubsection">
5789 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
5790</div>
5791
5792<div class="doc_text">
5793
5794<h5>Syntax:</h5>
5795<pre>
5796 declare void @llvm.stackrestore(i8 * %ptr)
5797</pre>
5798
5799<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5800<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5801 the function stack to the state it was in when the
5802 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5803 executed. This is useful for implementing language features like scoped
5804 automatic variable sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5805
5806<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5807<p>See the description
5808 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5809
5810</div>
5811
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5812<!-- _______________________________________________________________________ -->
5813<div class="doc_subsubsection">
5814 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
5815</div>
5816
5817<div class="doc_text">
5818
5819<h5>Syntax:</h5>
5820<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5821 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]5822</pre>
5823
5824<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5825<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5826 insert a prefetch instruction if supported; otherwise, it is a noop.
5827 Prefetches have no effect on the behavior of the program but can change its
5828 performance characteristics.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5829
5830<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5831<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5832 specifier determining if the fetch should be for a read (0) or write (1),
5833 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5834 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5835 and <tt>locality</tt> arguments must be constant integers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5836
5837<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5838<p>This intrinsic does not modify the behavior of the program. In particular,
5839 prefetches cannot trap and do not produce a value. On targets that support
5840 this intrinsic, the prefetch can provide hints to the processor cache for
5841 better performance.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5842
5843</div>
5844
5845<!-- _______________________________________________________________________ -->
5846<div class="doc_subsubsection">
5847 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
5848</div>
5849
5850<div class="doc_text">
5851
5852<h5>Syntax:</h5>
5853<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5854 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5855</pre>
5856
5857<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5858<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5859 Counter (PC) in a region of code to simulators and other tools. The method
5860 is target specific, but it is expected that the marker will use exported
5861 symbols to transmit the PC of the marker. The marker makes no guarantees
5862 that it will remain with any specific instruction after optimizations. It is
5863 possible that the presence of a marker will inhibit optimizations. The
5864 intended use is to be inserted after optimizations to allow correlations of
5865 simulation runs.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5866
5867<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5868<p><tt>id</tt> is a numerical id identifying the marker.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5869
5870<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5871<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]5872 not support this intrinsic may ignore it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5873
5874</div>
5875
5876<!-- _______________________________________________________________________ -->
5877<div class="doc_subsubsection">
5878 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5879</div>
5880
5881<div class="doc_text">
5882
5883<h5>Syntax:</h5>
5884<pre>
5885 declare i64 @llvm.readcyclecounter( )
5886</pre>
5887
5888<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5889<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5890 counter register (or similar low latency, high accuracy clocks) on those
5891 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5892 should map to RPCC. As the backing counters overflow quickly (on the order
5893 of 9 seconds on alpha), this should only be used for small timings.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5894
5895<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5896<p>When directly supported, reading the cycle counter should not modify any
5897 memory. Implementations are allowed to either return a application specific
5898 value or a system wide value. On backends without support, this is lowered
5899 to a constant 0.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5900
5901</div>
5902
5903<!-- ======================================================================= -->
5904<div class="doc_subsection">
5905 <a name="int_libc">Standard C Library Intrinsics</a>
5906</div>
5907
5908<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5909
5910<p>LLVM provides intrinsics for a few important standard C library functions.
5911 These intrinsics allow source-language front-ends to pass information about
5912 the alignment of the pointer arguments to the code generator, providing
5913 opportunity for more efficient code generation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5914
5915</div>
5916
5917<!-- _______________________________________________________________________ -->
5918<div class="doc_subsubsection">
5919 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
5920</div>
5921
5922<div class="doc_text">
5923
5924<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5925<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
Mon P Wang238462c2010-04-07 06:35:53 +0000[diff] [blame]5926 integer bit width and for different address spaces. Not all targets support
5927 all bit widths however.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5928
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5929<pre>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]5930 declare void @llvm.memcpy.p0i8.p0i8.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5931 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
5932 declare void @llvm.memcpy.p0i8.p0i8.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5933 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5934</pre>
5935
5936<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5937<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5938 source location to the destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5939
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5940<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]5941 intrinsics do not return a value, takes extra alignment/isvolatile arguments
5942 and the pointers can be in specified address spaces.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5943
5944<h5>Arguments:</h5>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]5945
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5946<p>The first argument is a pointer to the destination, the second is a pointer
5947 to the source. The third argument is an integer argument specifying the
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]5948 number of bytes to copy, the fourth argument is the alignment of the
5949 source and destination locations, and the fifth is a boolean indicating a
5950 volatile access.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5951
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]5952<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]5953 then the caller guarantees that both the source and destination pointers are
5954 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5955
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]5956<p>Volatile accesses should not be deleted if dead, but the access behavior is
5957 not very cleanly specified and it is unwise to depend on it.</p>
5958
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5959<h5>Semantics:</h5>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]5960
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5961<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5962 source location to the destination location, which are not allowed to
5963 overlap. It copies "len" bytes of memory over. If the argument is known to
5964 be aligned to some boundary, this can be specified as the fourth argument,
5965 otherwise it should be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5966
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5967</div>
5968
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5969<!-- _______________________________________________________________________ -->
5970<div class="doc_subsubsection">
5971 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
5972</div>
5973
5974<div class="doc_text">
5975
5976<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5977<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
Mon P Wang238462c2010-04-07 06:35:53 +0000[diff] [blame]5978 width and for different address space. Not all targets support all bit
5979 widths however.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5980
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5981<pre>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]5982 declare void @llvm.memmove.p0i8.p0i8.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5983 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
5984 declare void @llvm.memmove.p0i8.p0i8.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5985 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5986</pre>
5987
5988<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5989<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
5990 source location to the destination location. It is similar to the
5991 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
5992 overlap.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5993
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5994<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]5995 intrinsics do not return a value, takes extra alignment/isvolatile arguments
5996 and the pointers can be in specified address spaces.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5997
5998<h5>Arguments:</h5>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]5999
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6000<p>The first argument is a pointer to the destination, the second is a pointer
6001 to the source. The third argument is an integer argument specifying the
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6002 number of bytes to copy, the fourth argument is the alignment of the
6003 source and destination locations, and the fifth is a boolean indicating a
6004 volatile access.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6005
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]6006<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]6007 then the caller guarantees that the source and destination pointers are
6008 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6009
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6010<p>Volatile accesses should not be deleted if dead, but the access behavior is
6011 not very cleanly specified and it is unwise to depend on it.</p>
6012
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6013<h5>Semantics:</h5>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6014
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6015<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6016 source location to the destination location, which may overlap. It copies
6017 "len" bytes of memory over. If the argument is known to be aligned to some
6018 boundary, this can be specified as the fourth argument, otherwise it should
6019 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6020
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6021</div>
6022
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6023<!-- _______________________________________________________________________ -->
6024<div class="doc_subsubsection">
6025 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
6026</div>
6027
6028<div class="doc_text">
6029
6030<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]6031<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
Mon P Wang238462c2010-04-07 06:35:53 +0000[diff] [blame]6032 width and for different address spaces. Not all targets support all bit
6033 widths however.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6034
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6035<pre>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6036 declare void @llvm.memset.p0i8.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerc0dfafe2010-04-08 00:54:34 +0000[diff] [blame]6037 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6038 declare void @llvm.memset.p0i8.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerc0dfafe2010-04-08 00:54:34 +0000[diff] [blame]6039 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6040</pre>
6041
6042<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6043<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6044 particular byte value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6045
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6046<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6047 intrinsic does not return a value, takes extra alignment/volatile arguments,
6048 and the destination can be in an arbitrary address space.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6049
6050<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6051<p>The first argument is a pointer to the destination to fill, the second is the
6052 byte value to fill it with, the third argument is an integer argument
6053 specifying the number of bytes to fill, and the fourth argument is the known
6054 alignment of destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6055
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]6056<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]6057 then the caller guarantees that the destination pointer is aligned to that
6058 boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6059
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6060<p>Volatile accesses should not be deleted if dead, but the access behavior is
6061 not very cleanly specified and it is unwise to depend on it.</p>
6062
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6063<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6064<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6065 at the destination location. If the argument is known to be aligned to some
6066 boundary, this can be specified as the fourth argument, otherwise it should
6067 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6068
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6069</div>
6070
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6071<!-- _______________________________________________________________________ -->
6072<div class="doc_subsubsection">
6073 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
6074</div>
6075
6076<div class="doc_text">
6077
6078<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6079<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6080 floating point or vector of floating point type. Not all targets support all
6081 types however.</p>
6082
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6083<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]6084 declare float @llvm.sqrt.f32(float %Val)
6085 declare double @llvm.sqrt.f64(double %Val)
6086 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6087 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6088 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6089</pre>
6090
6091<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6092<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6093 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6094 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6095 behavior for negative numbers other than -0.0 (which allows for better
6096 optimization, because there is no need to worry about errno being
6097 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]6098
6099<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6100<p>The argument and return value are floating point numbers of the same
6101 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6102
6103<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6104<p>This function returns the sqrt of the specified operand if it is a
6105 nonnegative floating point number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6106
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6107</div>
6108
6109<!-- _______________________________________________________________________ -->
6110<div class="doc_subsubsection">
6111 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
6112</div>
6113
6114<div class="doc_text">
6115
6116<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6117<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6118 floating point or vector of floating point type. Not all targets support all
6119 types however.</p>
6120
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6121<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]6122 declare float @llvm.powi.f32(float %Val, i32 %power)
6123 declare double @llvm.powi.f64(double %Val, i32 %power)
6124 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6125 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6126 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6127</pre>
6128
6129<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6130<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6131 specified (positive or negative) power. The order of evaluation of
6132 multiplications is not defined. When a vector of floating point type is
6133 used, the second argument remains a scalar integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6134
6135<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6136<p>The second argument is an integer power, and the first is a value to raise to
6137 that power.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6138
6139<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6140<p>This function returns the first value raised to the second power with an
6141 unspecified sequence of rounding operations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6142
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6143</div>
6144
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6145<!-- _______________________________________________________________________ -->
6146<div class="doc_subsubsection">
6147 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6148</div>
6149
6150<div class="doc_text">
6151
6152<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6153<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6154 floating point or vector of floating point type. Not all targets support all
6155 types however.</p>
6156
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6157<pre>
6158 declare float @llvm.sin.f32(float %Val)
6159 declare double @llvm.sin.f64(double %Val)
6160 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6161 declare fp128 @llvm.sin.f128(fp128 %Val)
6162 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6163</pre>
6164
6165<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6166<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6167
6168<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6169<p>The argument and return value are floating point numbers of the same
6170 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6171
6172<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6173<p>This function returns the sine of the specified operand, returning the same
6174 values as the libm <tt>sin</tt> functions would, and handles error conditions
6175 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6176
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6177</div>
6178
6179<!-- _______________________________________________________________________ -->
6180<div class="doc_subsubsection">
6181 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6182</div>
6183
6184<div class="doc_text">
6185
6186<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6187<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6188 floating point or vector of floating point type. Not all targets support all
6189 types however.</p>
6190
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6191<pre>
6192 declare float @llvm.cos.f32(float %Val)
6193 declare double @llvm.cos.f64(double %Val)
6194 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6195 declare fp128 @llvm.cos.f128(fp128 %Val)
6196 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6197</pre>
6198
6199<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6200<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6201
6202<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6203<p>The argument and return value are floating point numbers of the same
6204 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6205
6206<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6207<p>This function returns the cosine of the specified operand, returning the same
6208 values as the libm <tt>cos</tt> functions would, and handles error conditions
6209 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6210
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6211</div>
6212
6213<!-- _______________________________________________________________________ -->
6214<div class="doc_subsubsection">
6215 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6216</div>
6217
6218<div class="doc_text">
6219
6220<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6221<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6222 floating point or vector of floating point type. Not all targets support all
6223 types however.</p>
6224
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6225<pre>
6226 declare float @llvm.pow.f32(float %Val, float %Power)
6227 declare double @llvm.pow.f64(double %Val, double %Power)
6228 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6229 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6230 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6231</pre>
6232
6233<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6234<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6235 specified (positive or negative) power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6236
6237<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6238<p>The second argument is a floating point power, and the first is a value to
6239 raise to that power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6240
6241<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6242<p>This function returns the first value raised to the second power, returning
6243 the same values as the libm <tt>pow</tt> functions would, and handles error
6244 conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6245
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6246</div>
6247
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6248<!-- ======================================================================= -->
6249<div class="doc_subsection">
6250 <a name="int_manip">Bit Manipulation Intrinsics</a>
6251</div>
6252
6253<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6254
6255<p>LLVM provides intrinsics for a few important bit manipulation operations.
6256 These allow efficient code generation for some algorithms.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6257
6258</div>
6259
6260<!-- _______________________________________________________________________ -->
6261<div class="doc_subsubsection">
6262 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
6263</div>
6264
6265<div class="doc_text">
6266
6267<h5>Syntax:</h5>
6268<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6269 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6270
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6271<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6272 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6273 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6274 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6275</pre>
6276
6277<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6278<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6279 values with an even number of bytes (positive multiple of 16 bits). These
6280 are useful for performing operations on data that is not in the target's
6281 native byte order.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6282
6283<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6284<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6285 and low byte of the input i16 swapped. Similarly,
6286 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6287 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6288 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6289 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6290 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6291 more, respectively).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6292
6293</div>
6294
6295<!-- _______________________________________________________________________ -->
6296<div class="doc_subsubsection">
6297 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
6298</div>
6299
6300<div class="doc_text">
6301
6302<h5>Syntax:</h5>
6303<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]6304 width. Not all targets support all bit widths however.</p>
6305
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6306<pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6307 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6308 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6309 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6310 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6311 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6312</pre>
6313
6314<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6315<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6316 in a value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6317
6318<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6319<p>The only argument is the value to be counted. The argument may be of any
6320 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6321
6322<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6323<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]6324
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6325</div>
6326
6327<!-- _______________________________________________________________________ -->
6328<div class="doc_subsubsection">
6329 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
6330</div>
6331
6332<div class="doc_text">
6333
6334<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6335<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6336 integer bit width. Not all targets support all bit widths however.</p>
6337
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6338<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6339 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6340 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6341 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6342 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6343 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6344</pre>
6345
6346<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6347<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6348 leading zeros in a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6349
6350<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6351<p>The only argument is the value to be counted. The argument may be of any
6352 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6353
6354<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6355<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6356 zeros in a variable. If the src == 0 then the result is the size in bits of
6357 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6358
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6359</div>
6360
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6361<!-- _______________________________________________________________________ -->
6362<div class="doc_subsubsection">
6363 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
6364</div>
6365
6366<div class="doc_text">
6367
6368<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6369<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6370 integer bit width. Not all targets support all bit widths however.</p>
6371
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6372<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6373 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6374 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6375 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6376 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6377 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6378</pre>
6379
6380<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6381<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6382 trailing zeros.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6383
6384<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6385<p>The only argument is the value to be counted. The argument may be of any
6386 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6387
6388<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6389<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6390 zeros in a variable. If the src == 0 then the result is the size in bits of
6391 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6392
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6393</div>
6394
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6395<!-- ======================================================================= -->
6396<div class="doc_subsection">
6397 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6398</div>
6399
6400<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6401
6402<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6403
6404</div>
6405
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6406<!-- _______________________________________________________________________ -->
6407<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6408 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6409</div>
6410
6411<div class="doc_text">
6412
6413<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6414<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]6415 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6416
6417<pre>
6418 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6419 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6420 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6421</pre>
6422
6423<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6424<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6425 a signed addition of the two arguments, and indicate whether an overflow
6426 occurred during the signed summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6427
6428<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6429<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]6430 be of integer types of any bit width, but they must have the same bit
6431 width. The second element of the result structure must be of
6432 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6433 undergo signed addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6434
6435<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6436<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6437 a signed addition of the two variables. They return a structure &mdash; the
6438 first element of which is the signed summation, and the second element of
6439 which is a bit specifying if the signed summation resulted in an
6440 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6441
6442<h5>Examples:</h5>
6443<pre>
6444 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6445 %sum = extractvalue {i32, i1} %res, 0
6446 %obit = extractvalue {i32, i1} %res, 1
6447 br i1 %obit, label %overflow, label %normal
6448</pre>
6449
6450</div>
6451
6452<!-- _______________________________________________________________________ -->
6453<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6454 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6455</div>
6456
6457<div class="doc_text">
6458
6459<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6460<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]6461 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6462
6463<pre>
6464 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6465 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6466 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6467</pre>
6468
6469<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6470<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6471 an unsigned addition of the two arguments, and indicate whether a carry
6472 occurred during the unsigned summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6473
6474<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6475<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]6476 be of integer types of any bit width, but they must have the same bit
6477 width. The second element of the result structure must be of
6478 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6479 undergo unsigned addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6480
6481<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6482<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6483 an unsigned addition of the two arguments. They return a structure &mdash;
6484 the first element of which is the sum, and the second element of which is a
6485 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6486
6487<h5>Examples:</h5>
6488<pre>
6489 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6490 %sum = extractvalue {i32, i1} %res, 0
6491 %obit = extractvalue {i32, i1} %res, 1
6492 br i1 %obit, label %carry, label %normal
6493</pre>
6494
6495</div>
6496
6497<!-- _______________________________________________________________________ -->
6498<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6499 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6500</div>
6501
6502<div class="doc_text">
6503
6504<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6505<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]6506 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6507
6508<pre>
6509 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6510 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6511 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6512</pre>
6513
6514<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6515<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6516 a signed subtraction of the two arguments, and indicate whether an overflow
6517 occurred during the signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6518
6519<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6520<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]6521 be of integer types of any bit width, but they must have the same bit
6522 width. The second element of the result structure must be of
6523 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6524 undergo signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6525
6526<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6527<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6528 a signed subtraction of the two arguments. They return a structure &mdash;
6529 the first element of which is the subtraction, and the second element of
6530 which is a bit specifying if the signed subtraction resulted in an
6531 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6532
6533<h5>Examples:</h5>
6534<pre>
6535 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6536 %sum = extractvalue {i32, i1} %res, 0
6537 %obit = extractvalue {i32, i1} %res, 1
6538 br i1 %obit, label %overflow, label %normal
6539</pre>
6540
6541</div>
6542
6543<!-- _______________________________________________________________________ -->
6544<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6545 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6546</div>
6547
6548<div class="doc_text">
6549
6550<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6551<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]6552 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6553
6554<pre>
6555 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6556 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6557 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6558</pre>
6559
6560<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6561<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6562 an unsigned subtraction of the two arguments, and indicate whether an
6563 overflow occurred during the unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6564
6565<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6566<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]6567 be of integer types of any bit width, but they must have the same bit
6568 width. The second element of the result structure must be of
6569 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6570 undergo unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6571
6572<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6573<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6574 an unsigned subtraction of the two arguments. They return a structure &mdash;
6575 the first element of which is the subtraction, and the second element of
6576 which is a bit specifying if the unsigned subtraction resulted in an
6577 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6578
6579<h5>Examples:</h5>
6580<pre>
6581 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6582 %sum = extractvalue {i32, i1} %res, 0
6583 %obit = extractvalue {i32, i1} %res, 1
6584 br i1 %obit, label %overflow, label %normal
6585</pre>
6586
6587</div>
6588
6589<!-- _______________________________________________________________________ -->
6590<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6591 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6592</div>
6593
6594<div class="doc_text">
6595
6596<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6597<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]6598 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6599
6600<pre>
6601 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6602 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6603 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6604</pre>
6605
6606<h5>Overview:</h5>
6607
6608<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6609 a signed multiplication of the two arguments, and indicate whether an
6610 overflow occurred during the signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6611
6612<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6613<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]6614 be of integer types of any bit width, but they must have the same bit
6615 width. The second element of the result structure must be of
6616 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6617 undergo signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6618
6619<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6620<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6621 a signed multiplication of the two arguments. They return a structure &mdash;
6622 the first element of which is the multiplication, and the second element of
6623 which is a bit specifying if the signed multiplication resulted in an
6624 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6625
6626<h5>Examples:</h5>
6627<pre>
6628 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6629 %sum = extractvalue {i32, i1} %res, 0
6630 %obit = extractvalue {i32, i1} %res, 1
6631 br i1 %obit, label %overflow, label %normal
6632</pre>
6633
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6634</div>
6635
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6636<!-- _______________________________________________________________________ -->
6637<div class="doc_subsubsection">
6638 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6639</div>
6640
6641<div class="doc_text">
6642
6643<h5>Syntax:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6644<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]6645 on any integer bit width.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6646
6647<pre>
6648 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6649 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6650 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6651</pre>
6652
6653<h5>Overview:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6654<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6655 a unsigned multiplication of the two arguments, and indicate whether an
6656 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6657
6658<h5>Arguments:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6659<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]6660 be of integer types of any bit width, but they must have the same bit
6661 width. The second element of the result structure must be of
6662 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6663 undergo unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6664
6665<h5>Semantics:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6666<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6667 an unsigned multiplication of the two arguments. They return a structure
6668 &mdash; the first element of which is the multiplication, and the second
6669 element of which is a bit specifying if the unsigned multiplication resulted
6670 in an overflow.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6671
6672<h5>Examples:</h5>
6673<pre>
6674 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6675 %sum = extractvalue {i32, i1} %res, 0
6676 %obit = extractvalue {i32, i1} %res, 1
6677 br i1 %obit, label %overflow, label %normal
6678</pre>
6679
6680</div>
6681
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6682<!-- ======================================================================= -->
6683<div class="doc_subsection">
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]6684 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
6685</div>
6686
6687<div class="doc_text">
6688
Chris Lattnere5969c62010-03-15 04:12:21 +0000[diff] [blame]6689<p>Half precision floating point is a storage-only format. This means that it is
6690 a dense encoding (in memory) but does not support computation in the
6691 format.</p>
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6692
Chris Lattnere5969c62010-03-15 04:12:21 +0000[diff] [blame]6693<p>This means that code must first load the half-precision floating point
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6694 value as an i16, then convert it to float with <a
6695 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
6696 Computation can then be performed on the float value (including extending to
Chris Lattnere5969c62010-03-15 04:12:21 +0000[diff] [blame]6697 double etc). To store the value back to memory, it is first converted to
6698 float if needed, then converted to i16 with
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6699 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
6700 storing as an i16 value.</p>
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]6701</div>
6702
6703<!-- _______________________________________________________________________ -->
6704<div class="doc_subsubsection">
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6705 <a name="int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a>
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]6706</div>
6707
6708<div class="doc_text">
6709
6710<h5>Syntax:</h5>
6711<pre>
6712 declare i16 @llvm.convert.to.fp16(f32 %a)
6713</pre>
6714
6715<h5>Overview:</h5>
6716<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6717 a conversion from single precision floating point format to half precision
6718 floating point format.</p>
6719
6720<h5>Arguments:</h5>
6721<p>The intrinsic function contains single argument - the value to be
6722 converted.</p>
6723
6724<h5>Semantics:</h5>
6725<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6726 a conversion from single precision floating point format to half precision
Chris Lattnere5969c62010-03-15 04:12:21 +0000[diff] [blame]6727 floating point format. The return value is an <tt>i16</tt> which
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6728 contains the converted number.</p>
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]6729
6730<h5>Examples:</h5>
6731<pre>
6732 %res = call i16 @llvm.convert.to.fp16(f32 %a)
6733 store i16 %res, i16* @x, align 2
6734</pre>
6735
6736</div>
6737
6738<!-- _______________________________________________________________________ -->
6739<div class="doc_subsubsection">
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6740 <a name="int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a>
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]6741</div>
6742
6743<div class="doc_text">
6744
6745<h5>Syntax:</h5>
6746<pre>
6747 declare f32 @llvm.convert.from.fp16(i16 %a)
6748</pre>
6749
6750<h5>Overview:</h5>
6751<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
6752 a conversion from half precision floating point format to single precision
6753 floating point format.</p>
6754
6755<h5>Arguments:</h5>
6756<p>The intrinsic function contains single argument - the value to be
6757 converted.</p>
6758
6759<h5>Semantics:</h5>
6760<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattnere5969c62010-03-15 04:12:21 +0000[diff] [blame]6761 conversion from half single precision floating point format to single
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6762 precision floating point format. The input half-float value is represented by
6763 an <tt>i16</tt> value.</p>
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]6764
6765<h5>Examples:</h5>
6766<pre>
6767 %a = load i16* @x, align 2
6768 %res = call f32 @llvm.convert.from.fp16(i16 %a)
6769</pre>
6770
6771</div>
6772
6773<!-- ======================================================================= -->
6774<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6775 <a name="int_debugger">Debugger Intrinsics</a>
6776</div>
6777
6778<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6779
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6780<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6781 prefix), are described in
6782 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6783 Level Debugging</a> document.</p>
6784
6785</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6786
6787<!-- ======================================================================= -->
6788<div class="doc_subsection">
6789 <a name="int_eh">Exception Handling Intrinsics</a>
6790</div>
6791
6792<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6793
6794<p>The LLVM exception handling intrinsics (which all start with
6795 <tt>llvm.eh.</tt> prefix), are described in
6796 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6797 Handling</a> document.</p>
6798
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6799</div>
6800
6801<!-- ======================================================================= -->
6802<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6803 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6804</div>
6805
6806<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6807
6808<p>This intrinsic makes it possible to excise one parameter, marked with
6809 the <tt>nest</tt> attribute, from a function. The result is a callable
6810 function pointer lacking the nest parameter - the caller does not need to
6811 provide a value for it. Instead, the value to use is stored in advance in a
6812 "trampoline", a block of memory usually allocated on the stack, which also
6813 contains code to splice the nest value into the argument list. This is used
6814 to implement the GCC nested function address extension.</p>
6815
6816<p>For example, if the function is
6817 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6818 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6819 follows:</p>
6820
6821<div class="doc_code">
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6822<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6823 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6824 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6825 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6826 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6827</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6828</div>
6829
6830<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6831 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6832
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6833</div>
6834
6835<!-- _______________________________________________________________________ -->
6836<div class="doc_subsubsection">
6837 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6838</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6839
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6840<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6841
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6842<h5>Syntax:</h5>
6843<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6844 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]6845</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6846
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6847<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6848<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6849 function pointer suitable for executing it.</p>
6850
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6851<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6852<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6853 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6854 sufficiently aligned block of memory; this memory is written to by the
6855 intrinsic. Note that the size and the alignment are target-specific - LLVM
6856 currently provides no portable way of determining them, so a front-end that
6857 generates this intrinsic needs to have some target-specific knowledge.
6858 The <tt>func</tt> argument must hold a function bitcast to
6859 an <tt>i8*</tt>.</p>
6860
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6861<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6862<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6863 dependent code, turning it into a function. A pointer to this function is
6864 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6865 function pointer type</a> before being called. The new function's signature
6866 is the same as that of <tt>func</tt> with any arguments marked with
6867 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6868 is allowed, and it must be of pointer type. Calling the new function is
6869 equivalent to calling <tt>func</tt> with the same argument list, but
6870 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6871 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6872 by <tt>tramp</tt> is modified, then the effect of any later call to the
6873 returned function pointer is undefined.</p>
6874
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6875</div>
6876
6877<!-- ======================================================================= -->
6878<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6879 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6880</div>
6881
6882<div class="doc_text">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6883
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6884<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6885 hardware constructs for atomic operations and memory synchronization. This
6886 provides an interface to the hardware, not an interface to the programmer. It
6887 is aimed at a low enough level to allow any programming models or APIs
6888 (Application Programming Interfaces) which need atomic behaviors to map
6889 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6890 hardware provides a "universal IR" for source languages, it also provides a
6891 starting point for developing a "universal" atomic operation and
6892 synchronization IR.</p>
6893
6894<p>These do <em>not</em> form an API such as high-level threading libraries,
6895 software transaction memory systems, atomic primitives, and intrinsic
6896 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6897 application libraries. The hardware interface provided by LLVM should allow
6898 a clean implementation of all of these APIs and parallel programming models.
6899 No one model or paradigm should be selected above others unless the hardware
6900 itself ubiquitously does so.</p>
6901
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6902</div>
6903
6904<!-- _______________________________________________________________________ -->
6905<div class="doc_subsubsection">
6906 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6907</div>
6908<div class="doc_text">
6909<h5>Syntax:</h5>
6910<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6911 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]6912</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6913
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6914<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6915<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6916 specific pairs of memory access types.</p>
6917
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6918<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6919<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6920 The first four arguments enables a specific barrier as listed below. The
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]6921 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6922 memory.</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6923
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6924<ul>
6925 <li><tt>ll</tt>: load-load barrier</li>
6926 <li><tt>ls</tt>: load-store barrier</li>
6927 <li><tt>sl</tt>: store-load barrier</li>
6928 <li><tt>ss</tt>: store-store barrier</li>
6929 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6930</ul>
6931
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6932<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6933<p>This intrinsic causes the system to enforce some ordering constraints upon
6934 the loads and stores of the program. This barrier does not
6935 indicate <em>when</em> any events will occur, it only enforces
6936 an <em>order</em> in which they occur. For any of the specified pairs of load
6937 and store operations (f.ex. load-load, or store-load), all of the first
6938 operations preceding the barrier will complete before any of the second
6939 operations succeeding the barrier begin. Specifically the semantics for each
6940 pairing is as follows:</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6941
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6942<ul>
6943 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6944 after the barrier begins.</li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]6945 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6946 store after the barrier begins.</li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]6947 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6948 store after the barrier begins.</li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]6949 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6950 load after the barrier begins.</li>
6951</ul>
6952
6953<p>These semantics are applied with a logical "and" behavior when more than one
6954 is enabled in a single memory barrier intrinsic.</p>
6955
6956<p>Backends may implement stronger barriers than those requested when they do
6957 not support as fine grained a barrier as requested. Some architectures do
6958 not need all types of barriers and on such architectures, these become
6959 noops.</p>
6960
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6961<h5>Example:</h5>
6962<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6963%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6964%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6965 store i32 4, %ptr
6966
6967%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6968 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6969 <i>; guarantee the above finishes</i>
6970 store i32 8, %ptr <i>; before this begins</i>
6971</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6972
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6973</div>
6974
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6975<!-- _______________________________________________________________________ -->
6976<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6977 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6978</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6979
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6980<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6981
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6982<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6983<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6984 any integer bit width and for different address spaces. Not all targets
6985 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6986
6987<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6988 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6989 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6990 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6991 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]6992</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6993
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6994<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6995<p>This loads a value in memory and compares it to a given value. If they are
6996 equal, it stores a new value into the memory.</p>
6997
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6998<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6999<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
7000 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
7001 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
7002 this integer type. While any bit width integer may be used, targets may only
7003 lower representations they support in hardware.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7004
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7005<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7006<p>This entire intrinsic must be executed atomically. It first loads the value
7007 in memory pointed to by <tt>ptr</tt> and compares it with the
7008 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
7009 memory. The loaded value is yielded in all cases. This provides the
7010 equivalent of an atomic compare-and-swap operation within the SSA
7011 framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7012
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7013<h5>Examples:</h5>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7014<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7015%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7016%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7017 store i32 4, %ptr
7018
7019%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7020%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7021 <i>; yields {i32}:result1 = 4</i>
7022%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7023%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7024
7025%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7026%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7027 <i>; yields {i32}:result2 = 8</i>
7028%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
7029
7030%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
7031</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7032
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7033</div>
7034
7035<!-- _______________________________________________________________________ -->
7036<div class="doc_subsubsection">
7037 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
7038</div>
7039<div class="doc_text">
7040<h5>Syntax:</h5>
7041
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7042<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
7043 integer bit width. Not all targets support all bit widths however.</p>
7044
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7045<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7046 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
7047 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
7048 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
7049 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]7050</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7051
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7052<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7053<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
7054 the value from memory. It then stores the value in <tt>val</tt> in the memory
7055 at <tt>ptr</tt>.</p>
7056
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7057<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7058<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
7059 the <tt>val</tt> argument and the result must be integers of the same bit
7060 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
7061 integer type. The targets may only lower integer representations they
7062 support.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7063
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7064<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7065<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
7066 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
7067 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7068
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7069<h5>Examples:</h5>
7070<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7071%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7072%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7073 store i32 4, %ptr
7074
7075%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7076%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7077 <i>; yields {i32}:result1 = 4</i>
7078%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7079%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7080
7081%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7082%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7083 <i>; yields {i32}:result2 = 8</i>
7084
7085%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
7086%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
7087</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7088
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7089</div>
7090
7091<!-- _______________________________________________________________________ -->
7092<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7093 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7094
7095</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7096
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7097<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7098
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7099<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7100<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
7101 any integer bit width. Not all targets support all bit widths however.</p>
7102
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7103<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7104 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7105 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7106 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7107 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]7108</pre>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7109
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7110<h5>Overview:</h5>
7111<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
7112 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7113
7114<h5>Arguments:</h5>
7115<p>The intrinsic takes two arguments, the first a pointer to an integer value
7116 and the second an integer value. The result is also an integer value. These
7117 integer types can have any bit width, but they must all have the same bit
7118 width. The targets may only lower integer representations they support.</p>
7119
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7120<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7121<p>This intrinsic does a series of operations atomically. It first loads the
7122 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
7123 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]7124
7125<h5>Examples:</h5>
7126<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7127%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7128%ptr = bitcast i8* %mallocP to i32*
7129 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7130%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7131 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7132%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7133 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7134%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7135 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7136%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7137</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7138
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7139</div>
7140
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7141<!-- _______________________________________________________________________ -->
7142<div class="doc_subsubsection">
7143 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
7144
7145</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7146
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7147<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7148
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7149<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7150<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
7151 any integer bit width and for different address spaces. Not all targets
7152 support all bit widths however.</p>
7153
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7154<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7155 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7156 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7157 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7158 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]7159</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7160
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7161<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7162<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7163 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7164
7165<h5>Arguments:</h5>
7166<p>The intrinsic takes two arguments, the first a pointer to an integer value
7167 and the second an integer value. The result is also an integer value. These
7168 integer types can have any bit width, but they must all have the same bit
7169 width. The targets may only lower integer representations they support.</p>
7170
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7171<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7172<p>This intrinsic does a series of operations atomically. It first loads the
7173 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
7174 result to <tt>ptr</tt>. It yields the original value stored
7175 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7176
7177<h5>Examples:</h5>
7178<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7179%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7180%ptr = bitcast i8* %mallocP to i32*
7181 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7182%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7183 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7184%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7185 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7186%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7187 <i>; yields {i32}:result3 = 2</i>
7188%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
7189</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7190
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7191</div>
7192
7193<!-- _______________________________________________________________________ -->
7194<div class="doc_subsubsection">
7195 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
7196 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
7197 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
7198 <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]7199</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7200
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7201<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7202
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7203<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7204<p>These are overloaded intrinsics. You can
7205 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
7206 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7207 bit width and for different address spaces. Not all targets support all bit
7208 widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7209
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7210<pre>
7211 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7212 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7213 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7214 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]7215</pre>
7216
7217<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7218 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7219 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7220 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7221 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]7222</pre>
7223
7224<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7225 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7226 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7227 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7228 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]7229</pre>
7230
7231<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7232 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7233 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7234 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7235 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]7236</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7237
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7238<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7239<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7240 the value stored in memory at <tt>ptr</tt>. It yields the original value
7241 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7242
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7243<h5>Arguments:</h5>
7244<p>These intrinsics take two arguments, the first a pointer to an integer value
7245 and the second an integer value. The result is also an integer value. These
7246 integer types can have any bit width, but they must all have the same bit
7247 width. The targets may only lower integer representations they support.</p>
7248
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7249<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7250<p>These intrinsics does a series of operations atomically. They first load the
7251 value stored at <tt>ptr</tt>. They then do the bitwise
7252 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7253 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7254
7255<h5>Examples:</h5>
7256<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7257%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7258%ptr = bitcast i8* %mallocP to i32*
7259 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7260%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7261 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7262%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7263 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7264%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7265 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7266%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7267 <i>; yields {i32}:result3 = FF</i>
7268%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7269</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7270
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7271</div>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7272
7273<!-- _______________________________________________________________________ -->
7274<div class="doc_subsubsection">
7275 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7276 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7277 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7278 <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]7279</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7280
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7281<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7282
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7283<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7284<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7285 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7286 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7287 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7288
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7289<pre>
7290 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7291 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7292 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7293 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]7294</pre>
7295
7296<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7297 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7298 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7299 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7300 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]7301</pre>
7302
7303<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7304 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7305 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7306 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7307 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]7308</pre>
7309
7310<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7311 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7312 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7313 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7314 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]7315</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7316
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7317<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7318<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7319 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7320 original value at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7321
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7322<h5>Arguments:</h5>
7323<p>These intrinsics take two arguments, the first a pointer to an integer value
7324 and the second an integer value. The result is also an integer value. These
7325 integer types can have any bit width, but they must all have the same bit
7326 width. The targets may only lower integer representations they support.</p>
7327
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7328<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7329<p>These intrinsics does a series of operations atomically. They first load the
7330 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7331 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7332 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7333
7334<h5>Examples:</h5>
7335<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7336%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7337%ptr = bitcast i8* %mallocP to i32*
7338 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7339%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7340 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7341%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7342 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7343%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7344 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7345%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7346 <i>; yields {i32}:result3 = 8</i>
7347%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7348</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7349
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7350</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7351
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7352
7353<!-- ======================================================================= -->
7354<div class="doc_subsection">
7355 <a name="int_memorymarkers">Memory Use Markers</a>
7356</div>
7357
7358<div class="doc_text">
7359
7360<p>This class of intrinsics exists to information about the lifetime of memory
7361 objects and ranges where variables are immutable.</p>
7362
7363</div>
7364
7365<!-- _______________________________________________________________________ -->
7366<div class="doc_subsubsection">
7367 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7368</div>
7369
7370<div class="doc_text">
7371
7372<h5>Syntax:</h5>
7373<pre>
7374 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7375</pre>
7376
7377<h5>Overview:</h5>
7378<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7379 object's lifetime.</p>
7380
7381<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7382<p>The first argument is a constant integer representing the size of the
7383 object, or -1 if it is variable sized. The second argument is a pointer to
7384 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7385
7386<h5>Semantics:</h5>
7387<p>This intrinsic indicates that before this point in the code, the value of the
7388 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]7389 never be used and has an undefined value. A load from the pointer that
7390 precedes this intrinsic can be replaced with
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7391 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7392
7393</div>
7394
7395<!-- _______________________________________________________________________ -->
7396<div class="doc_subsubsection">
7397 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7398</div>
7399
7400<div class="doc_text">
7401
7402<h5>Syntax:</h5>
7403<pre>
7404 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7405</pre>
7406
7407<h5>Overview:</h5>
7408<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7409 object's lifetime.</p>
7410
7411<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7412<p>The first argument is a constant integer representing the size of the
7413 object, or -1 if it is variable sized. The second argument is a pointer to
7414 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7415
7416<h5>Semantics:</h5>
7417<p>This intrinsic indicates that after this point in the code, the value of the
7418 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7419 never be used and has an undefined value. Any stores into the memory object
7420 following this intrinsic may be removed as dead.
7421
7422</div>
7423
7424<!-- _______________________________________________________________________ -->
7425<div class="doc_subsubsection">
7426 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7427</div>
7428
7429<div class="doc_text">
7430
7431<h5>Syntax:</h5>
7432<pre>
7433 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7434</pre>
7435
7436<h5>Overview:</h5>
7437<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7438 a memory object will not change.</p>
7439
7440<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7441<p>The first argument is a constant integer representing the size of the
7442 object, or -1 if it is variable sized. The second argument is a pointer to
7443 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7444
7445<h5>Semantics:</h5>
7446<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7447 the return value, the referenced memory location is constant and
7448 unchanging.</p>
7449
7450</div>
7451
7452<!-- _______________________________________________________________________ -->
7453<div class="doc_subsubsection">
7454 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7455</div>
7456
7457<div class="doc_text">
7458
7459<h5>Syntax:</h5>
7460<pre>
7461 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7462</pre>
7463
7464<h5>Overview:</h5>
7465<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7466 a memory object are mutable.</p>
7467
7468<h5>Arguments:</h5>
7469<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7470 The second argument is a constant integer representing the size of the
7471 object, or -1 if it is variable sized and the third argument is a pointer
7472 to the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7473
7474<h5>Semantics:</h5>
7475<p>This intrinsic indicates that the memory is mutable again.</p>
7476
7477</div>
7478
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7479<!-- ======================================================================= -->
7480<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7481 <a name="int_general">General Intrinsics</a>
7482</div>
7483
7484<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7485
7486<p>This class of intrinsics is designed to be generic and has no specific
7487 purpose.</p>
7488
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7489</div>
7490
7491<!-- _______________________________________________________________________ -->
7492<div class="doc_subsubsection">
7493 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7494</div>
7495
7496<div class="doc_text">
7497
7498<h5>Syntax:</h5>
7499<pre>
7500 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7501</pre>
7502
7503<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7504<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7505
7506<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7507<p>The first argument is a pointer to a value, the second is a pointer to a
7508 global string, the third is a pointer to a global string which is the source
7509 file name, and the last argument is the line number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7510
7511<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7512<p>This intrinsic allows annotation of local variables with arbitrary strings.
7513 This can be useful for special purpose optimizations that want to look for
7514 these annotations. These have no other defined use, they are ignored by code
7515 generation and optimization.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7516
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7517</div>
7518
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7519<!-- _______________________________________________________________________ -->
7520<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]7521 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7522</div>
7523
7524<div class="doc_text">
7525
7526<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7527<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7528 any integer bit width.</p>
7529
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7530<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +0000[diff] [blame]7531 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7532 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7533 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7534 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7535 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]7536</pre>
7537
7538<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7539<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7540
7541<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7542<p>The first argument is an integer value (result of some expression), the
7543 second is a pointer to a global string, the third is a pointer to a global
7544 string which is the source file name, and the last argument is the line
7545 number. It returns the value of the first argument.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7546
7547<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7548<p>This intrinsic allows annotations to be put on arbitrary expressions with
7549 arbitrary strings. This can be useful for special purpose optimizations that
7550 want to look for these annotations. These have no other defined use, they
7551 are ignored by code generation and optimization.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7552
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7553</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7554
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7555<!-- _______________________________________________________________________ -->
7556<div class="doc_subsubsection">
7557 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7558</div>
7559
7560<div class="doc_text">
7561
7562<h5>Syntax:</h5>
7563<pre>
7564 declare void @llvm.trap()
7565</pre>
7566
7567<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7568<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7569
7570<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7571<p>None.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7572
7573<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7574<p>This intrinsics is lowered to the target dependent trap instruction. If the
7575 target does not have a trap instruction, this intrinsic will be lowered to
7576 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7577
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7578</div>
7579
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7580<!-- _______________________________________________________________________ -->
7581<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +0000[diff] [blame]7582 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7583</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7584
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7585<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7586
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7587<h5>Syntax:</h5>
7588<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7589 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7590</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7591
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7592<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7593<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7594 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7595 ensure that it is placed on the stack before local variables.</p>
7596
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7597<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7598<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7599 arguments. The first argument is the value loaded from the stack
7600 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7601 that has enough space to hold the value of the guard.</p>
7602
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7603<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7604<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7605 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7606 stack. This is to ensure that if a local variable on the stack is
7607 overwritten, it will destroy the value of the guard. When the function exits,
7608 the guard on the stack is checked against the original guard. If they're
7609 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7610 function.</p>
7611
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7612</div>
7613
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7614<!-- _______________________________________________________________________ -->
7615<div class="doc_subsubsection">
7616 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7617</div>
7618
7619<div class="doc_text">
7620
7621<h5>Syntax:</h5>
7622<pre>
Eric Christopher0101f9d2009-12-23 00:29:49 +0000[diff] [blame]7623 declare i32 @llvm.objectsize.i32( i8* &lt;object&gt;, i1 &lt;type&gt; )
7624 declare i64 @llvm.objectsize.i64( i8* &lt;object&gt;, i1 &lt;type&gt; )
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7625</pre>
7626
7627<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7628<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information
Eric Christopher184f44d2010-01-08 21:42:39 +0000[diff] [blame]7629 to the optimizers to discover at compile time either a) when an
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7630 operation like memcpy will either overflow a buffer that corresponds to
7631 an object, or b) to determine that a runtime check for overflow isn't
7632 necessary. An object in this context means an allocation of a
Eric Christopher0101f9d2009-12-23 00:29:49 +0000[diff] [blame]7633 specific class, structure, array, or other object.</p>
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7634
7635<h5>Arguments:</h5>
7636<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher0101f9d2009-12-23 00:29:49 +0000[diff] [blame]7637 argument is a pointer to or into the <tt>object</tt>. The second argument
7638 is a boolean 0 or 1. This argument determines whether you want the
7639 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
7640 1, variables are not allowed.</p>
7641
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7642<h5>Semantics:</h5>
7643<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7644 representing the size of the object concerned or <tt>i32/i64 -1 or 0</tt>
7645 (depending on the <tt>type</tt> argument if the size cannot be determined
7646 at compile time.</p>
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7647
7648</div>
7649
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7650<!-- *********************************************************************** -->
7651<hr>
7652<address>
7653 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
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Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7657
7658 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
7659 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
7660 Last modified: $Date$
7661</address>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]7662
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7663</body>
7664</html>