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5 <title>LLVM Assembly Language Reference Manual</title>
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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.">
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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>
Jeffrey Yasskin6dc467f2010-04-26 21:21:24 +0000[diff] [blame]53 <li><a href="#volatile">Volatile Memory Accesses</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]54 </ol>
55 </li>
56 <li><a href="#typesystem">Type System</a>
57 <ol>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]58 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]59 <li><a href="#t_primitive">Primitive Types</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]60 <ol>
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]61 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]62 <li><a href="#t_floating">Floating Point Types</a></li>
63 <li><a href="#t_void">Void Type</a></li>
64 <li><a href="#t_label">Label Type</a></li>
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]65 <li><a href="#t_metadata">Metadata Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]66 </ol>
67 </li>
68 <li><a href="#t_derived">Derived Types</a>
69 <ol>
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]70 <li><a href="#t_aggregate">Aggregate Types</a>
71 <ol>
72 <li><a href="#t_array">Array Type</a></li>
73 <li><a href="#t_struct">Structure Type</a></li>
74 <li><a href="#t_pstruct">Packed Structure Type</a></li>
75 <li><a href="#t_union">Union Type</a></li>
76 <li><a href="#t_vector">Vector Type</a></li>
77 </ol>
78 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]79 <li><a href="#t_function">Function Type</a></li>
80 <li><a href="#t_pointer">Pointer Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]81 <li><a href="#t_opaque">Opaque Type</a></li>
82 </ol>
83 </li>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]84 <li><a href="#t_uprefs">Type Up-references</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]85 </ol>
86 </li>
87 <li><a href="#constants">Constants</a>
88 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]89 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]90 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]91 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
92 <li><a href="#undefvalues">Undefined Values</a></li>
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]93 <li><a href="#trapvalues">Trap Values</a></li>
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]94 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]95 <li><a href="#constantexprs">Constant Expressions</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]96 </ol>
97 </li>
98 <li><a href="#othervalues">Other Values</a>
99 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]100 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]101 <li><a href="#metadata">Metadata Nodes and Metadata Strings</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]102 </ol>
103 </li>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]104 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
105 <ol>
106 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]107 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
108 Global Variable</a></li>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]109 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
110 Global Variable</a></li>
111 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
112 Global Variable</a></li>
113 </ol>
114 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]115 <li><a href="#instref">Instruction Reference</a>
116 <ol>
117 <li><a href="#terminators">Terminator Instructions</a>
118 <ol>
119 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
120 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
121 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]122 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]123 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
124 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
125 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
126 </ol>
127 </li>
128 <li><a href="#binaryops">Binary Operations</a>
129 <ol>
130 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]131 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]132 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]133 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]134 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]135 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]136 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
137 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
138 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
139 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
140 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
141 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
142 </ol>
143 </li>
144 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
145 <ol>
146 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
147 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
148 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
149 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
150 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
151 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
152 </ol>
153 </li>
154 <li><a href="#vectorops">Vector Operations</a>
155 <ol>
156 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
157 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
158 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
159 </ol>
160 </li>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]161 <li><a href="#aggregateops">Aggregate Operations</a>
162 <ol>
163 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
164 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
165 </ol>
166 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]167 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
168 <ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]169 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
170 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
171 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
172 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
173 </ol>
174 </li>
175 <li><a href="#convertops">Conversion Operations</a>
176 <ol>
177 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
178 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
179 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
180 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
181 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
182 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
183 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
184 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
185 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
186 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
187 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
188 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
189 </ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]190 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]191 <li><a href="#otherops">Other Operations</a>
192 <ol>
193 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
194 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
195 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
196 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
197 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
198 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
199 </ol>
200 </li>
201 </ol>
202 </li>
203 <li><a href="#intrinsics">Intrinsic Functions</a>
204 <ol>
205 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
206 <ol>
207 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
208 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
209 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
210 </ol>
211 </li>
212 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
213 <ol>
214 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
215 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
216 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
217 </ol>
218 </li>
219 <li><a href="#int_codegen">Code Generator Intrinsics</a>
220 <ol>
221 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
222 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
223 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
224 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
225 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
226 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
227 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
228 </ol>
229 </li>
230 <li><a href="#int_libc">Standard C Library Intrinsics</a>
231 <ol>
232 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
233 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
234 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
235 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
236 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]237 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
238 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
239 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]240 </ol>
241 </li>
242 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
243 <ol>
244 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
245 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
246 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
247 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]248 </ol>
249 </li>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]250 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
251 <ol>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]252 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
253 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
254 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
255 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
256 <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]257 <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]258 </ol>
259 </li>
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]260 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
261 <ol>
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]262 <li><a href="#int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
263 <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]264 </ol>
265 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]266 <li><a href="#int_debugger">Debugger intrinsics</a></li>
267 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]268 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]269 <ol>
270 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]271 </ol>
272 </li>
Bill Wendling9127adb2008-11-18 22:10:53 +0000[diff] [blame]273 <li><a href="#int_atomics">Atomic intrinsics</a>
274 <ol>
275 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
276 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
277 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
278 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
279 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
280 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
281 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
282 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
283 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
284 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
285 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
286 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
287 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
288 </ol>
289 </li>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]290 <li><a href="#int_memorymarkers">Memory Use Markers</a>
291 <ol>
292 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
293 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
294 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
295 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
296 </ol>
297 </li>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]298 <li><a href="#int_general">General intrinsics</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]299 <ol>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]300 <li><a href="#int_var_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]301 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]302 <li><a href="#int_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]303 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]304 <li><a href="#int_trap">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]305 '<tt>llvm.trap</tt>' Intrinsic</a></li>
306 <li><a href="#int_stackprotector">
307 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]308 <li><a href="#int_objectsize">
309 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]310 </ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]311 </li>
312 </ol>
313 </li>
314</ol>
315
316<div class="doc_author">
317 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
318 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
319</div>
320
321<!-- *********************************************************************** -->
322<div class="doc_section"> <a name="abstract">Abstract </a></div>
323<!-- *********************************************************************** -->
324
325<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]326
327<p>This document is a reference manual for the LLVM assembly language. LLVM is
328 a Static Single Assignment (SSA) based representation that provides type
329 safety, low-level operations, flexibility, and the capability of representing
330 'all' high-level languages cleanly. It is the common code representation
331 used throughout all phases of the LLVM compilation strategy.</p>
332
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]333</div>
334
335<!-- *********************************************************************** -->
336<div class="doc_section"> <a name="introduction">Introduction</a> </div>
337<!-- *********************************************************************** -->
338
339<div class="doc_text">
340
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]341<p>The LLVM code representation is designed to be used in three different forms:
342 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
343 for fast loading by a Just-In-Time compiler), and as a human readable
344 assembly language representation. This allows LLVM to provide a powerful
345 intermediate representation for efficient compiler transformations and
346 analysis, while providing a natural means to debug and visualize the
347 transformations. The three different forms of LLVM are all equivalent. This
348 document describes the human readable representation and notation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]349
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]350<p>The LLVM representation aims to be light-weight and low-level while being
351 expressive, typed, and extensible at the same time. It aims to be a
352 "universal IR" of sorts, by being at a low enough level that high-level ideas
353 may be cleanly mapped to it (similar to how microprocessors are "universal
354 IR's", allowing many source languages to be mapped to them). By providing
355 type information, LLVM can be used as the target of optimizations: for
356 example, through pointer analysis, it can be proven that a C automatic
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]357 variable is never accessed outside of the current function, allowing it to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]358 be promoted to a simple SSA value instead of a memory location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]359
360</div>
361
362<!-- _______________________________________________________________________ -->
363<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
364
365<div class="doc_text">
366
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]367<p>It is important to note that this document describes 'well formed' LLVM
368 assembly language. There is a difference between what the parser accepts and
369 what is considered 'well formed'. For example, the following instruction is
370 syntactically okay, but not well formed:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]371
372<div class="doc_code">
373<pre>
374%x = <a href="#i_add">add</a> i32 1, %x
375</pre>
376</div>
377
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]378<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
379 LLVM infrastructure provides a verification pass that may be used to verify
380 that an LLVM module is well formed. This pass is automatically run by the
381 parser after parsing input assembly and by the optimizer before it outputs
382 bitcode. The violations pointed out by the verifier pass indicate bugs in
383 transformation passes or input to the parser.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]384
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]385</div>
386
Chris Lattnera83fdc02007-10-03 17:34:29 +0000[diff] [blame]387<!-- Describe the typesetting conventions here. -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]388
389<!-- *********************************************************************** -->
390<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
391<!-- *********************************************************************** -->
392
393<div class="doc_text">
394
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]395<p>LLVM identifiers come in two basic types: global and local. Global
396 identifiers (functions, global variables) begin with the <tt>'@'</tt>
397 character. Local identifiers (register names, types) begin with
398 the <tt>'%'</tt> character. Additionally, there are three different formats
399 for identifiers, for different purposes:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]400
401<ol>
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]402 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]403 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
404 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
405 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
406 other characters in their names can be surrounded with quotes. Special
407 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
408 ASCII code for the character in hexadecimal. In this way, any character
409 can be used in a name value, even quotes themselves.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]410
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]411 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]412 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]413
414 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]415 constants</a>, below.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]416</ol>
417
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]418<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]419 don't need to worry about name clashes with reserved words, and the set of
420 reserved words may be expanded in the future without penalty. Additionally,
421 unnamed identifiers allow a compiler to quickly come up with a temporary
422 variable without having to avoid symbol table conflicts.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]423
424<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]425 languages. There are keywords for different opcodes
426 ('<tt><a href="#i_add">add</a></tt>',
427 '<tt><a href="#i_bitcast">bitcast</a></tt>',
428 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
429 ('<tt><a href="#t_void">void</a></tt>',
430 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
431 reserved words cannot conflict with variable names, because none of them
432 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]433
434<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]435 '<tt>%X</tt>' by 8:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]436
437<p>The easy way:</p>
438
439<div class="doc_code">
440<pre>
441%result = <a href="#i_mul">mul</a> i32 %X, 8
442</pre>
443</div>
444
445<p>After strength reduction:</p>
446
447<div class="doc_code">
448<pre>
449%result = <a href="#i_shl">shl</a> i32 %X, i8 3
450</pre>
451</div>
452
453<p>And the hard way:</p>
454
455<div class="doc_code">
456<pre>
Gabor Greifc0ea7672009-10-28 13:05:07 +0000[diff] [blame]457%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
458%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]459%result = <a href="#i_add">add</a> i32 %1, %1
460</pre>
461</div>
462
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]463<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
464 lexical features of LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]465
466<ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]467 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]468 line.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]469
470 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]471 assigned to a named value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]472
473 <li>Unnamed temporaries are numbered sequentially</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]474</ol>
475
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]476<p>It also shows a convention that we follow in this document. When
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]477 demonstrating instructions, we will follow an instruction with a comment that
478 defines the type and name of value produced. Comments are shown in italic
479 text.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]480
481</div>
482
483<!-- *********************************************************************** -->
484<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
485<!-- *********************************************************************** -->
486
487<!-- ======================================================================= -->
488<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
489</div>
490
491<div class="doc_text">
492
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]493<p>LLVM programs are composed of "Module"s, each of which is a translation unit
494 of the input programs. Each module consists of functions, global variables,
495 and symbol table entries. Modules may be combined together with the LLVM
496 linker, which merges function (and global variable) definitions, resolves
497 forward declarations, and merges symbol table entries. Here is an example of
498 the "hello world" module:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]499
500<div class="doc_code">
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]501<pre>
502<i>; Declare the string constant as a global constant.</i>
503<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]504
505<i>; External declaration of the puts function</i>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]506<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]507
508<i>; Definition of main function</i>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]509define i32 @main() { <i>; i32()* </i>
510 <i>; Convert [13 x i8]* to i8 *...</i>
511 %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]512
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]513 <i>; Call puts function to write out the string to stdout.</i>
514 <a href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]515 <a href="#i_ret">ret</a> i32 0<br>}
516
517<i>; Named metadata</i>
518!1 = metadata !{i32 41}
519!foo = !{!1, null}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]520</pre>
521</div>
522
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]523<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]524 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]525 a <a href="#functionstructure">function definition</a> for
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]526 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
527 "<tt>foo"</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]528
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]529<p>In general, a module is made up of a list of global values, where both
530 functions and global variables are global values. Global values are
531 represented by a pointer to a memory location (in this case, a pointer to an
532 array of char, and a pointer to a function), and have one of the
533 following <a href="#linkage">linkage types</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]534
535</div>
536
537<!-- ======================================================================= -->
538<div class="doc_subsection">
539 <a name="linkage">Linkage Types</a>
540</div>
541
542<div class="doc_text">
543
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]544<p>All Global Variables and Functions have one of the following types of
545 linkage:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]546
547<dl>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]548 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]549 <dd>Global values with private linkage are only directly accessible by objects
550 in the current module. In particular, linking code into a module with an
551 private global value may cause the private to be renamed as necessary to
552 avoid collisions. Because the symbol is private to the module, all
553 references can be updated. This doesn't show up in any symbol table in the
554 object file.</dd>
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000[diff] [blame]555
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]556 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]557 <dd>Similar to private, but the symbol is passed through the assembler and
Chris Lattner06c1ecc2009-08-24 04:32:16 +0000[diff] [blame]558 removed by the linker after evaluation. Note that (unlike private
559 symbols) linker_private symbols are subject to coalescing by the linker:
560 weak symbols get merged and redefinitions are rejected. However, unlike
561 normal strong symbols, they are removed by the linker from the final
562 linked image (executable or dynamic library).</dd>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]563
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]564 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]565 <dd>Similar to private, but the value shows as a local symbol
566 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
567 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]568
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]569 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]570 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]571 into the object file corresponding to the LLVM module. They exist to
572 allow inlining and other optimizations to take place given knowledge of
573 the definition of the global, which is known to be somewhere outside the
574 module. Globals with <tt>available_externally</tt> linkage are allowed to
575 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
576 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]577
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]578 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]579 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattnerd16c5512010-01-09 19:15:14 +0000[diff] [blame]580 the same name when linkage occurs. This can be used to implement
581 some forms of inline functions, templates, or other code which must be
582 generated in each translation unit that uses it, but where the body may
583 be overridden with a more definitive definition later. Unreferenced
584 <tt>linkonce</tt> globals are allowed to be discarded. Note that
585 <tt>linkonce</tt> linkage does not actually allow the optimizer to
586 inline the body of this function into callers because it doesn't know if
587 this definition of the function is the definitive definition within the
588 program or whether it will be overridden by a stronger definition.
589 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
590 linkage.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]591
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]592 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]593 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
594 <tt>linkonce</tt> linkage, except that unreferenced globals with
595 <tt>weak</tt> linkage may not be discarded. This is used for globals that
596 are declared "weak" in C source code.</dd>
597
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]598 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]599 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
600 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
601 global scope.
602 Symbols with "<tt>common</tt>" linkage are merged in the same way as
603 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattner83c4a712009-08-05 05:41:44 +0000[diff] [blame]604 <tt>common</tt> symbols may not have an explicit section,
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]605 must have a zero initializer, and may not be marked '<a
Chris Lattner83c4a712009-08-05 05:41:44 +0000[diff] [blame]606 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
607 have common linkage.</dd>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]608
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]609
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]610 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]611 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]612 pointer to array type. When two global variables with appending linkage
613 are linked together, the two global arrays are appended together. This is
614 the LLVM, typesafe, equivalent of having the system linker append together
615 "sections" with identical names when .o files are linked.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]616
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]617 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]618 <dd>The semantics of this linkage follow the ELF object file model: the symbol
619 is weak until linked, if not linked, the symbol becomes null instead of
620 being an undefined reference.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]621
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]622 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
623 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]624 <dd>Some languages allow differing globals to be merged, such as two functions
625 with different semantics. Other languages, such as <tt>C++</tt>, ensure
626 that only equivalent globals are ever merged (the "one definition rule" -
627 "ODR"). Such languages can use the <tt>linkonce_odr</tt>
628 and <tt>weak_odr</tt> linkage types to indicate that the global will only
629 be merged with equivalent globals. These linkage types are otherwise the
630 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]631
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]632 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]633 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]634 visible, meaning that it participates in linkage and can be used to
635 resolve external symbol references.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]636</dl>
637
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]638<p>The next two types of linkage are targeted for Microsoft Windows platform
639 only. They are designed to support importing (exporting) symbols from (to)
640 DLLs (Dynamic Link Libraries).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]641
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]642<dl>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]643 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]644 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]645 or variable via a global pointer to a pointer that is set up by the DLL
646 exporting the symbol. On Microsoft Windows targets, the pointer name is
647 formed by combining <code>__imp_</code> and the function or variable
648 name.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]649
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]650 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]651 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]652 pointer to a pointer in a DLL, so that it can be referenced with the
653 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
654 name is formed by combining <code>__imp_</code> and the function or
655 variable name.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]656</dl>
657
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]658<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
659 another module defined a "<tt>.LC0</tt>" variable and was linked with this
660 one, one of the two would be renamed, preventing a collision. Since
661 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
662 declarations), they are accessible outside of the current module.</p>
663
664<p>It is illegal for a function <i>declaration</i> to have any linkage type
665 other than "externally visible", <tt>dllimport</tt>
666 or <tt>extern_weak</tt>.</p>
667
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]668<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]669 or <tt>weak_odr</tt> linkages.</p>
670
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]671</div>
672
673<!-- ======================================================================= -->
674<div class="doc_subsection">
675 <a name="callingconv">Calling Conventions</a>
676</div>
677
678<div class="doc_text">
679
680<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]681 and <a href="#i_invoke">invokes</a> can all have an optional calling
682 convention specified for the call. The calling convention of any pair of
683 dynamic caller/callee must match, or the behavior of the program is
684 undefined. The following calling conventions are supported by LLVM, and more
685 may be added in the future:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]686
687<dl>
688 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]689 <dd>This calling convention (the default if no other calling convention is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]690 specified) matches the target C calling conventions. This calling
691 convention supports varargs function calls and tolerates some mismatch in
692 the declared prototype and implemented declaration of the function (as
693 does normal C).</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]694
695 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]696 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]697 (e.g. by passing things in registers). This calling convention allows the
698 target to use whatever tricks it wants to produce fast code for the
699 target, without having to conform to an externally specified ABI
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]700 (Application Binary Interface).
701 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattnerac9a9392010-03-11 00:22:57 +0000[diff] [blame]702 when this or the GHC convention is used.</a> This calling convention
703 does not support varargs and requires the prototype of all callees to
704 exactly match the prototype of the function definition.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]705
706 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]707 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]708 as possible under the assumption that the call is not commonly executed.
709 As such, these calls often preserve all registers so that the call does
710 not break any live ranges in the caller side. This calling convention
711 does not support varargs and requires the prototype of all callees to
712 exactly match the prototype of the function definition.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]713
Chris Lattnerac9a9392010-03-11 00:22:57 +0000[diff] [blame]714 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
715 <dd>This calling convention has been implemented specifically for use by the
716 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
717 It passes everything in registers, going to extremes to achieve this by
718 disabling callee save registers. This calling convention should not be
719 used lightly but only for specific situations such as an alternative to
720 the <em>register pinning</em> performance technique often used when
721 implementing functional programming languages.At the moment only X86
722 supports this convention and it has the following limitations:
723 <ul>
724 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
725 floating point types are supported.</li>
726 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
727 6 floating point parameters.</li>
728 </ul>
729 This calling convention supports
730 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
731 requires both the caller and callee are using it.
732 </dd>
733
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]734 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]735 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]736 target-specific calling conventions to be used. Target specific calling
737 conventions start at 64.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]738</dl>
739
740<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]741 support Pascal conventions or any other well-known target-independent
742 convention.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]743
744</div>
745
746<!-- ======================================================================= -->
747<div class="doc_subsection">
748 <a name="visibility">Visibility Styles</a>
749</div>
750
751<div class="doc_text">
752
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]753<p>All Global Variables and Functions have one of the following visibility
754 styles:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]755
756<dl>
757 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]758 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]759 that the declaration is visible to other modules and, in shared libraries,
760 means that the declared entity may be overridden. On Darwin, default
761 visibility means that the declaration is visible to other modules. Default
762 visibility corresponds to "external linkage" in the language.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]763
764 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]765 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]766 object if they are in the same shared object. Usually, hidden visibility
767 indicates that the symbol will not be placed into the dynamic symbol
768 table, so no other module (executable or shared library) can reference it
769 directly.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]770
771 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]772 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]773 the dynamic symbol table, but that references within the defining module
774 will bind to the local symbol. That is, the symbol cannot be overridden by
775 another module.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]776</dl>
777
778</div>
779
780<!-- ======================================================================= -->
781<div class="doc_subsection">
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]782 <a name="namedtypes">Named Types</a>
783</div>
784
785<div class="doc_text">
786
787<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]788 it easier to read the IR and make the IR more condensed (particularly when
789 recursive types are involved). An example of a name specification is:</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]790
791<div class="doc_code">
792<pre>
793%mytype = type { %mytype*, i32 }
794</pre>
795</div>
796
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]797<p>You may give a name to any <a href="#typesystem">type</a> except
798 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
799 is expected with the syntax "%mytype".</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]800
801<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]802 and that you can therefore specify multiple names for the same type. This
803 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
804 uses structural typing, the name is not part of the type. When printing out
805 LLVM IR, the printer will pick <em>one name</em> to render all types of a
806 particular shape. This means that if you have code where two different
807 source types end up having the same LLVM type, that the dumper will sometimes
808 print the "wrong" or unexpected type. This is an important design point and
809 isn't going to change.</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]810
811</div>
812
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]813<!-- ======================================================================= -->
814<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]815 <a name="globalvars">Global Variables</a>
816</div>
817
818<div class="doc_text">
819
820<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]821 instead of run-time. Global variables may optionally be initialized, may
822 have an explicit section to be placed in, and may have an optional explicit
823 alignment specified. A variable may be defined as "thread_local", which
824 means that it will not be shared by threads (each thread will have a
825 separated copy of the variable). A variable may be defined as a global
826 "constant," which indicates that the contents of the variable
827 will <b>never</b> be modified (enabling better optimization, allowing the
828 global data to be placed in the read-only section of an executable, etc).
829 Note that variables that need runtime initialization cannot be marked
830 "constant" as there is a store to the variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]831
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]832<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
833 constant, even if the final definition of the global is not. This capability
834 can be used to enable slightly better optimization of the program, but
835 requires the language definition to guarantee that optimizations based on the
836 'constantness' are valid for the translation units that do not include the
837 definition.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]838
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]839<p>As SSA values, global variables define pointer values that are in scope
840 (i.e. they dominate) all basic blocks in the program. Global variables
841 always define a pointer to their "content" type because they describe a
842 region of memory, and all memory objects in LLVM are accessed through
843 pointers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]844
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]845<p>A global variable may be declared to reside in a target-specific numbered
846 address space. For targets that support them, address spaces may affect how
847 optimizations are performed and/or what target instructions are used to
848 access the variable. The default address space is zero. The address space
849 qualifier must precede any other attributes.</p>
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]850
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]851<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]852 supports it, it will emit globals to the section specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]853
Chris Lattner72413b22010-04-28 00:13:42 +0000[diff] [blame]854<p>An explicit alignment may be specified for a global, which must be a power
855 of 2. If not present, or if the alignment is set to zero, the alignment of
856 the global is set by the target to whatever it feels convenient. If an
857 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner50d07d02010-04-28 00:31:12 +0000[diff] [blame]858 alignment. Targets and optimizers are not allowed to over-align the global
859 if the global has an assigned section. In this case, the extra alignment
860 could be observable: for example, code could assume that the globals are
861 densely packed in their section and try to iterate over them as an array,
862 alignment padding would break this iteration.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]863
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]864<p>For example, the following defines a global in a numbered address space with
865 an initializer, section, and alignment:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]866
867<div class="doc_code">
868<pre>
Dan Gohman21ef02c2009-01-11 00:40:00 +0000[diff] [blame]869@G = addrspace(5) constant float 1.0, section "foo", align 4
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]870</pre>
871</div>
872
873</div>
874
875
876<!-- ======================================================================= -->
877<div class="doc_subsection">
878 <a name="functionstructure">Functions</a>
879</div>
880
881<div class="doc_text">
882
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]883<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]884 optional <a href="#linkage">linkage type</a>, an optional
885 <a href="#visibility">visibility style</a>, an optional
886 <a href="#callingconv">calling convention</a>, a return type, an optional
887 <a href="#paramattrs">parameter attribute</a> for the return type, a function
888 name, a (possibly empty) argument list (each with optional
889 <a href="#paramattrs">parameter attributes</a>), optional
890 <a href="#fnattrs">function attributes</a>, an optional section, an optional
891 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
892 curly brace, a list of basic blocks, and a closing curly brace.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]893
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]894<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
895 optional <a href="#linkage">linkage type</a>, an optional
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]896 <a href="#visibility">visibility style</a>, an optional
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]897 <a href="#callingconv">calling convention</a>, a return type, an optional
898 <a href="#paramattrs">parameter attribute</a> for the return type, a function
899 name, a possibly empty list of arguments, an optional alignment, and an
900 optional <a href="#gc">garbage collector name</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]901
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]902<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]903 (Control Flow Graph) for the function. Each basic block may optionally start
904 with a label (giving the basic block a symbol table entry), contains a list
905 of instructions, and ends with a <a href="#terminators">terminator</a>
906 instruction (such as a branch or function return).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]907
908<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]909 executed on entrance to the function, and it is not allowed to have
910 predecessor basic blocks (i.e. there can not be any branches to the entry
911 block of a function). Because the block can have no predecessors, it also
912 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]913
914<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]915 supports it, it will emit functions to the section specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]916
917<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]918 the alignment is set to zero, the alignment of the function is set by the
919 target to whatever it feels convenient. If an explicit alignment is
920 specified, the function is forced to have at least that much alignment. All
921 alignments must be a power of 2.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]922
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]923<h5>Syntax:</h5>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]924<div class="doc_code">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]925<pre>
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]926define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]927 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
928 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
929 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
930 [<a href="#gc">gc</a>] { ... }
931</pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]932</div>
933
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]934</div>
935
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]936<!-- ======================================================================= -->
937<div class="doc_subsection">
938 <a name="aliasstructure">Aliases</a>
939</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]940
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]941<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]942
943<p>Aliases act as "second name" for the aliasee value (which can be either
944 function, global variable, another alias or bitcast of global value). Aliases
945 may have an optional <a href="#linkage">linkage type</a>, and an
946 optional <a href="#visibility">visibility style</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]947
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]948<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]949<div class="doc_code">
950<pre>
Duncan Sandsd7bfabf2008-09-12 20:48:21 +0000[diff] [blame]951@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]952</pre>
953</div>
954
955</div>
956
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]957<!-- ======================================================================= -->
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]958<div class="doc_subsection">
959 <a name="namedmetadatastructure">Named Metadata</a>
960</div>
961
962<div class="doc_text">
963
Chris Lattnerd0d96292010-01-15 21:50:19 +0000[diff] [blame]964<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
965 nodes</a> (but not metadata strings) and null are the only valid operands for
966 a named metadata.</p>
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]967
968<h5>Syntax:</h5>
969<div class="doc_code">
970<pre>
971!1 = metadata !{metadata !"one"}
972!name = !{null, !1}
973</pre>
974</div>
975
976</div>
977
978<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]979<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]980
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]981<div class="doc_text">
982
983<p>The return type and each parameter of a function type may have a set of
984 <i>parameter attributes</i> associated with them. Parameter attributes are
985 used to communicate additional information about the result or parameters of
986 a function. Parameter attributes are considered to be part of the function,
987 not of the function type, so functions with different parameter attributes
988 can have the same function type.</p>
989
990<p>Parameter attributes are simple keywords that follow the type specified. If
991 multiple parameter attributes are needed, they are space separated. For
992 example:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]993
994<div class="doc_code">
995<pre>
Nick Lewycky3022a742009-02-15 23:06:14 +0000[diff] [blame]996declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]997declare i32 @atoi(i8 zeroext)
998declare signext i8 @returns_signed_char()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]999</pre>
1000</div>
1001
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1002<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1003 <tt>readonly</tt>) come immediately after the argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1004
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1005<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]1006
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1007<dl>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1008 <dt><tt><b>zeroext</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 zero-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>signext</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1014 <dd>This indicates to the code generator that the parameter or return value
1015 should be sign-extended to a 32-bit value by the caller (for a parameter)
1016 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]1017
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1018 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1019 <dd>This indicates that this parameter or return value should be treated in a
1020 special target-dependent fashion during while emitting code for a function
1021 call or return (usually, by putting it in a register as opposed to memory,
1022 though some targets use it to distinguish between two different kinds of
1023 registers). Use of this attribute is target-specific.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]1024
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1025 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1026 <dd>This indicates that the pointer parameter should really be passed by value
1027 to the function. The attribute implies that a hidden copy of the pointee
1028 is made between the caller and the callee, so the callee is unable to
1029 modify the value in the callee. This attribute is only valid on LLVM
1030 pointer arguments. It is generally used to pass structs and arrays by
1031 value, but is also valid on pointers to scalars. The copy is considered
1032 to belong to the caller not the callee (for example,
1033 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1034 <tt>byval</tt> parameters). This is not a valid attribute for return
1035 values. The byval attribute also supports specifying an alignment with
1036 the align attribute. This has a target-specific effect on the code
1037 generator that usually indicates a desired alignment for the synthesized
1038 stack slot.</dd>
1039
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1040 <dt><tt><b>sret</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1041 <dd>This indicates that the pointer parameter specifies the address of a
1042 structure that is the return value of the function in the source program.
1043 This pointer must be guaranteed by the caller to be valid: loads and
1044 stores to the structure may be assumed by the callee to not to trap. This
1045 may only be applied to the first parameter. This is not a valid attribute
1046 for return values. </dd>
1047
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1048 <dt><tt><b>noalias</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1049 <dd>This indicates that the pointer does not alias any global or any other
1050 parameter. The caller is responsible for ensuring that this is the
1051 case. On a function return value, <tt>noalias</tt> additionally indicates
1052 that the pointer does not alias any other pointers visible to the
1053 caller. For further details, please see the discussion of the NoAlias
1054 response in
1055 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
1056 analysis</a>.</dd>
1057
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1058 <dt><tt><b>nocapture</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1059 <dd>This indicates that the callee does not make any copies of the pointer
1060 that outlive the callee itself. This is not a valid attribute for return
1061 values.</dd>
1062
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1063 <dt><tt><b>nest</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1064 <dd>This indicates that the pointer parameter can be excised using the
1065 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1066 attribute for return values.</dd>
1067</dl>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1068
1069</div>
1070
1071<!-- ======================================================================= -->
1072<div class="doc_subsection">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1073 <a name="gc">Garbage Collector Names</a>
1074</div>
1075
1076<div class="doc_text">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1077
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1078<p>Each function may specify a garbage collector name, which is simply a
1079 string:</p>
1080
1081<div class="doc_code">
1082<pre>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1083define void @f() gc "name" { ... }
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1084</pre>
1085</div>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1086
1087<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1088 collector which will cause the compiler to alter its output in order to
1089 support the named garbage collection algorithm.</p>
1090
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1091</div>
1092
1093<!-- ======================================================================= -->
1094<div class="doc_subsection">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1095 <a name="fnattrs">Function Attributes</a>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1096</div>
1097
1098<div class="doc_text">
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 set to communicate additional information about a
1101 function. Function attributes are considered to be part of the function, not
1102 of the function type, so functions with different parameter attributes can
1103 have the same function type.</p>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1104
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1105<p>Function attributes are simple keywords that follow the type specified. If
1106 multiple attributes are needed, they are space separated. For example:</p>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1107
1108<div class="doc_code">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1109<pre>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1110define void @f() noinline { ... }
1111define void @f() alwaysinline { ... }
1112define void @f() alwaysinline optsize { ... }
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1113define void @f() optsize { ... }
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1114</pre>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1115</div>
1116
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1117<dl>
Charles Davisfaa8f752010-02-12 00:31:15 +0000[diff] [blame]1118 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1119 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1120 the backend should forcibly align the stack pointer. Specify the
1121 desired alignment, which must be a power of two, in parentheses.
1122
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1123 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1124 <dd>This attribute indicates that the inliner should attempt to inline this
1125 function into callers whenever possible, ignoring any active inlining size
1126 threshold for this caller.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1127
Jakob Stoklund Olesen77180732010-02-06 01:16:28 +0000[diff] [blame]1128 <dt><tt><b>inlinehint</b></tt></dt>
1129 <dd>This attribute indicates that the source code contained a hint that inlining
1130 this function is desirable (such as the "inline" keyword in C/C++). It
1131 is just a hint; it imposes no requirements on the inliner.</dd>
1132
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1133 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1134 <dd>This attribute indicates that the inliner should never inline this
1135 function in any situation. This attribute may not be used together with
1136 the <tt>alwaysinline</tt> attribute.</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>optsize</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1139 <dd>This attribute suggests that optimization passes and code generator passes
1140 make choices that keep the code size of this function low, and otherwise
1141 do optimizations specifically to reduce code size.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1142
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1143 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1144 <dd>This function attribute indicates that the function never returns
1145 normally. This produces undefined behavior at runtime if the function
1146 ever does dynamically return.</dd>
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1147
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1148 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1149 <dd>This function attribute indicates that the function never returns with an
1150 unwind or exceptional control flow. If the function does unwind, its
1151 runtime behavior is undefined.</dd>
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1152
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1153 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1154 <dd>This attribute indicates that the function computes its result (or decides
1155 to unwind an exception) based strictly on its arguments, without
1156 dereferencing any pointer arguments or otherwise accessing any mutable
1157 state (e.g. memory, control registers, etc) visible to caller functions.
1158 It does not write through any pointer arguments
1159 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1160 changes any state visible to callers. This means that it cannot unwind
1161 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1162 could use the <tt>unwind</tt> instruction.</dd>
Devang Patela2f9f412009-06-12 19:45:19 +0000[diff] [blame]1163
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1164 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1165 <dd>This attribute indicates that the function does not write through any
1166 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1167 arguments) or otherwise modify any state (e.g. memory, control registers,
1168 etc) visible to caller functions. It may dereference pointer arguments
1169 and read state that may be set in the caller. A readonly function always
1170 returns the same value (or unwinds an exception identically) when called
1171 with the same set of arguments and global state. It cannot unwind an
1172 exception by calling the <tt>C++</tt> exception throwing methods, but may
1173 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovedd7d112009-07-17 18:07:26 +0000[diff] [blame]1174
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1175 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1176 <dd>This attribute indicates that the function should emit a stack smashing
1177 protector. It is in the form of a "canary"&mdash;a random value placed on
1178 the stack before the local variables that's checked upon return from the
1179 function to see if it has been overwritten. A heuristic is used to
1180 determine if a function needs stack protectors or not.<br>
1181<br>
1182 If a function that has an <tt>ssp</tt> attribute is inlined into a
1183 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1184 function will have an <tt>ssp</tt> attribute.</dd>
1185
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1186 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1187 <dd>This attribute indicates that the function should <em>always</em> emit a
1188 stack smashing protector. This overrides
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1189 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1190<br>
1191 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1192 function that doesn't have an <tt>sspreq</tt> attribute or which has
1193 an <tt>ssp</tt> attribute, then the resulting function will have
1194 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1195
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1196 <dt><tt><b>noredzone</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1197 <dd>This attribute indicates that the code generator should not use a red
1198 zone, even if the target-specific ABI normally permits it.</dd>
1199
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1200 <dt><tt><b>noimplicitfloat</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1201 <dd>This attributes disables implicit floating point instructions.</dd>
1202
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1203 <dt><tt><b>naked</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1204 <dd>This attribute disables prologue / epilogue emission for the function.
1205 This can have very system-specific consequences.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1206</dl>
1207
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1208</div>
1209
1210<!-- ======================================================================= -->
1211<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1212 <a name="moduleasm">Module-Level Inline Assembly</a>
1213</div>
1214
1215<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1216
1217<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1218 the GCC "file scope inline asm" blocks. These blocks are internally
1219 concatenated by LLVM and treated as a single unit, but may be separated in
1220 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1221
1222<div class="doc_code">
1223<pre>
1224module asm "inline asm code goes here"
1225module asm "more can go here"
1226</pre>
1227</div>
1228
1229<p>The strings can contain any character by escaping non-printable characters.
1230 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]1231 for the number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1232
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1233<p>The inline asm code is simply printed to the machine code .s file when
1234 assembly code is generated.</p>
1235
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1236</div>
1237
1238<!-- ======================================================================= -->
1239<div class="doc_subsection">
1240 <a name="datalayout">Data Layout</a>
1241</div>
1242
1243<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1244
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1245<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1246 data is to be laid out in memory. The syntax for the data layout is
1247 simply:</p>
1248
1249<div class="doc_code">
1250<pre>
1251target datalayout = "<i>layout specification</i>"
1252</pre>
1253</div>
1254
1255<p>The <i>layout specification</i> consists of a list of specifications
1256 separated by the minus sign character ('-'). Each specification starts with
1257 a letter and may include other information after the letter to define some
1258 aspect of the data layout. The specifications accepted are as follows:</p>
1259
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1260<dl>
1261 <dt><tt>E</tt></dt>
1262 <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]1263 bits with the most significance have the lowest address location.</dd>
1264
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1265 <dt><tt>e</tt></dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1266 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1267 the bits with the least significance have the lowest address
1268 location.</dd>
1269
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1270 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1271 <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]1272 <i>preferred</i> alignments. All sizes are in bits. Specifying
1273 the <i>pref</i> alignment is optional. If omitted, the
1274 preceding <tt>:</tt> should be omitted too.</dd>
1275
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1276 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1277 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1278 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1279
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1280 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1281 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1282 <i>size</i>.</dd>
1283
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1284 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1285 <dd>This specifies the alignment for a floating point type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1286 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1287 (double).</dd>
1288
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1289 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1290 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1291 <i>size</i>.</dd>
1292
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1293 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1294 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1295 <i>size</i>.</dd>
Chris Lattnerece41802009-11-07 09:35:34 +0000[diff] [blame]1296
1297 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1298 <dd>This specifies a set of native integer widths for the target CPU
1299 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1300 "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]1301 this set are considered to support most general arithmetic
Chris Lattnerece41802009-11-07 09:35:34 +0000[diff] [blame]1302 operations efficiently.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1303</dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1304
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1305<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohmanfde3cd72010-04-28 00:36:01 +0000[diff] [blame]1306 default set of specifications which are then (possibly) overridden by the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1307 specifications in the <tt>datalayout</tt> keyword. The default specifications
1308 are given in this list:</p>
1309
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1310<ul>
1311 <li><tt>E</tt> - big endian</li>
Dan Gohmane78194f2010-02-23 02:44:03 +0000[diff] [blame]1312 <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]1313 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1314 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1315 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1316 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1317 <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]1318 alignment of 64-bits</li>
1319 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1320 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1321 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1322 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1323 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1324 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1325</ul>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1326
1327<p>When LLVM is determining the alignment for a given type, it uses the
1328 following rules:</p>
1329
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1330<ol>
1331 <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]1332 specification is used.</li>
1333
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1334 <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]1335 smallest integer type that is larger than the bitwidth of the sought type
1336 is used. If none of the specifications are larger than the bitwidth then
1337 the the largest integer type is used. For example, given the default
1338 specifications above, the i7 type will use the alignment of i8 (next
1339 largest) while both i65 and i256 will use the alignment of i64 (largest
1340 specified).</li>
1341
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1342 <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]1343 largest vector type that is smaller than the sought vector type will be
1344 used as a fall back. This happens because &lt;128 x double&gt; can be
1345 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1346</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1347
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1348</div>
1349
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1350<!-- ======================================================================= -->
1351<div class="doc_subsection">
1352 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1353</div>
1354
1355<div class="doc_text">
1356
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1357<p>Any memory access must be done through a pointer value associated
Andreas Bolka23bece42009-07-27 20:37:10 +0000[diff] [blame]1358with an address range of the memory access, otherwise the behavior
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1359is undefined. Pointer values are associated with address ranges
1360according to the following rules:</p>
1361
1362<ul>
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1363 <li>A pointer value formed from a
1364 <tt><a href="#i_getelementptr">getelementptr</a></tt> instruction
1365 is associated with the addresses associated with the first operand
1366 of the <tt>getelementptr</tt>.</li>
1367 <li>An address of a global variable is associated with the address
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1368 range of the variable's storage.</li>
1369 <li>The result value of an allocation instruction is associated with
1370 the address range of the allocated storage.</li>
1371 <li>A null pointer in the default address-space is associated with
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1372 no address.</li>
1373 <li>A pointer value formed by an
1374 <tt><a href="#i_inttoptr">inttoptr</a></tt> is associated with all
1375 address ranges of all pointer values that contribute (directly or
1376 indirectly) to the computation of the pointer's value.</li>
1377 <li>The result value of a
1378 <tt><a href="#i_bitcast">bitcast</a></tt> is associated with all
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1379 addresses associated with the operand of the <tt>bitcast</tt>.</li>
1380 <li>An integer constant other than zero or a pointer value returned
1381 from a function not defined within LLVM may be associated with address
1382 ranges allocated through mechanisms other than those provided by
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1383 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1384 allocated by mechanisms provided by LLVM.</li>
1385 </ul>
1386
1387<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1388<tt><a href="#i_load">load</a></tt> merely indicates the size and
1389alignment of the memory from which to load, as well as the
1390interpretation of the value. The first operand of a
1391<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1392and alignment of the store.</p>
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1393
1394<p>Consequently, type-based alias analysis, aka TBAA, aka
1395<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1396LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1397additional information which specialized optimization passes may use
1398to implement type-based alias analysis.</p>
1399
1400</div>
1401
Jeffrey Yasskin6dc467f2010-04-26 21:21:24 +0000[diff] [blame]1402<!-- ======================================================================= -->
1403<div class="doc_subsection">
1404 <a name="volatile">Volatile Memory Accesses</a>
1405</div>
1406
1407<div class="doc_text">
1408
1409<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1410href="#i_store"><tt>store</tt></a>s, and <a
1411href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1412The optimizers must not change the number of volatile operations or change their
1413order of execution relative to other volatile operations. The optimizers
1414<i>may</i> change the order of volatile operations relative to non-volatile
1415operations. This is not Java's "volatile" and has no cross-thread
1416synchronization behavior.</p>
1417
1418</div>
1419
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1420<!-- *********************************************************************** -->
1421<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1422<!-- *********************************************************************** -->
1423
1424<div class="doc_text">
1425
1426<p>The LLVM type system is one of the most important features of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1427 intermediate representation. Being typed enables a number of optimizations
1428 to be performed on the intermediate representation directly, without having
1429 to do extra analyses on the side before the transformation. A strong type
1430 system makes it easier to read the generated code and enables novel analyses
1431 and transformations that are not feasible to perform on normal three address
1432 code representations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1433
1434</div>
1435
1436<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1437<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1438Classifications</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1439
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1440<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1441
1442<p>The types fall into a few useful classifications:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1443
1444<table border="1" cellspacing="0" cellpadding="4">
1445 <tbody>
1446 <tr><th>Classification</th><th>Types</th></tr>
1447 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1448 <td><a href="#t_integer">integer</a></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1449 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
1450 </tr>
1451 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1452 <td><a href="#t_floating">floating point</a></td>
1453 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1454 </tr>
1455 <tr>
1456 <td><a name="t_firstclass">first class</a></td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1457 <td><a href="#t_integer">integer</a>,
1458 <a href="#t_floating">floating point</a>,
1459 <a href="#t_pointer">pointer</a>,
Dan Gohmanf6237db2008-06-18 18:42:13 +0000[diff] [blame]1460 <a href="#t_vector">vector</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1461 <a href="#t_struct">structure</a>,
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1462 <a href="#t_union">union</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1463 <a href="#t_array">array</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1464 <a href="#t_label">label</a>,
1465 <a href="#t_metadata">metadata</a>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1466 </td>
1467 </tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1468 <tr>
1469 <td><a href="#t_primitive">primitive</a></td>
1470 <td><a href="#t_label">label</a>,
1471 <a href="#t_void">void</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1472 <a href="#t_floating">floating point</a>,
1473 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1474 </tr>
1475 <tr>
1476 <td><a href="#t_derived">derived</a></td>
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1477 <td><a href="#t_array">array</a>,
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1478 <a href="#t_function">function</a>,
1479 <a href="#t_pointer">pointer</a>,
1480 <a href="#t_struct">structure</a>,
1481 <a href="#t_pstruct">packed structure</a>,
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1482 <a href="#t_union">union</a>,
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1483 <a href="#t_vector">vector</a>,
1484 <a href="#t_opaque">opaque</a>.
Dan Gohman032ba852008-10-14 16:32:04 +0000[diff] [blame]1485 </td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1486 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1487 </tbody>
1488</table>
1489
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1490<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1491 important. Values of these types are the only ones which can be produced by
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1492 instructions.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1493
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1494</div>
1495
1496<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1497<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1498
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1499<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1500
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1501<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1502 system.</p>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1503
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1504</div>
1505
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1506<!-- _______________________________________________________________________ -->
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1507<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1508
1509<div class="doc_text">
1510
1511<h5>Overview:</h5>
1512<p>The integer type is a very simple type that simply specifies an arbitrary
1513 bit width for the integer type desired. Any bit width from 1 bit to
1514 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1515
1516<h5>Syntax:</h5>
1517<pre>
1518 iN
1519</pre>
1520
1521<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1522 value.</p>
1523
1524<h5>Examples:</h5>
1525<table class="layout">
1526 <tr class="layout">
1527 <td class="left"><tt>i1</tt></td>
1528 <td class="left">a single-bit integer.</td>
1529 </tr>
1530 <tr class="layout">
1531 <td class="left"><tt>i32</tt></td>
1532 <td class="left">a 32-bit integer.</td>
1533 </tr>
1534 <tr class="layout">
1535 <td class="left"><tt>i1942652</tt></td>
1536 <td class="left">a really big integer of over 1 million bits.</td>
1537 </tr>
1538</table>
1539
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1540</div>
1541
1542<!-- _______________________________________________________________________ -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1543<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1544
1545<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1546
1547<table>
1548 <tbody>
1549 <tr><th>Type</th><th>Description</th></tr>
1550 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1551 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1552 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1553 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1554 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1555 </tbody>
1556</table>
1557
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1558</div>
1559
1560<!-- _______________________________________________________________________ -->
1561<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1562
1563<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1564
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1565<h5>Overview:</h5>
1566<p>The void type does not represent any value and has no size.</p>
1567
1568<h5>Syntax:</h5>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1569<pre>
1570 void
1571</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1572
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1573</div>
1574
1575<!-- _______________________________________________________________________ -->
1576<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1577
1578<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1579
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1580<h5>Overview:</h5>
1581<p>The label type represents code labels.</p>
1582
1583<h5>Syntax:</h5>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1584<pre>
1585 label
1586</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1587
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1588</div>
1589
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1590<!-- _______________________________________________________________________ -->
1591<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1592
1593<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1594
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1595<h5>Overview:</h5>
Nick Lewyckyeb021882009-09-27 23:27:42 +0000[diff] [blame]1596<p>The metadata type represents embedded metadata. No derived types may be
1597 created from metadata except for <a href="#t_function">function</a>
1598 arguments.
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1599
1600<h5>Syntax:</h5>
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1601<pre>
1602 metadata
1603</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1604
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1605</div>
1606
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1607
1608<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1609<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
1610
1611<div class="doc_text">
1612
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1613<p>The real power in LLVM comes from the derived types in the system. This is
1614 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1615 useful types. Each of these types contain one or more element types which
1616 may be a primitive type, or another derived type. For example, it is
1617 possible to have a two dimensional array, using an array as the element type
1618 of another array.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1619
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1620
1621</div>
1622
1623<!-- _______________________________________________________________________ -->
1624<div class="doc_subsubsection"> <a name="t_aggregate">Aggregate Types</a> </div>
1625
1626<div class="doc_text">
1627
1628<p>Aggregate Types are a subset of derived types that can contain multiple
1629 member types. <a href="#t_array">Arrays</a>,
1630 <a href="#t_struct">structs</a>, <a href="#t_vector">vectors</a> and
1631 <a href="#t_union">unions</a> are aggregate types.</p>
1632
1633</div>
1634
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1635</div>
1636
1637<!-- _______________________________________________________________________ -->
1638<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
1639
1640<div class="doc_text">
1641
1642<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1643<p>The array type is a very simple derived type that arranges elements
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1644 sequentially in memory. The array type requires a size (number of elements)
1645 and an underlying data type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1646
1647<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1648<pre>
1649 [&lt;# elements&gt; x &lt;elementtype&gt;]
1650</pre>
1651
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1652<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1653 be any type with a size.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1654
1655<h5>Examples:</h5>
1656<table class="layout">
1657 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1658 <td class="left"><tt>[40 x i32]</tt></td>
1659 <td class="left">Array of 40 32-bit integer values.</td>
1660 </tr>
1661 <tr class="layout">
1662 <td class="left"><tt>[41 x i32]</tt></td>
1663 <td class="left">Array of 41 32-bit integer values.</td>
1664 </tr>
1665 <tr class="layout">
1666 <td class="left"><tt>[4 x i8]</tt></td>
1667 <td class="left">Array of 4 8-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1668 </tr>
1669</table>
1670<p>Here are some examples of multidimensional arrays:</p>
1671<table class="layout">
1672 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1673 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1674 <td class="left">3x4 array of 32-bit integer values.</td>
1675 </tr>
1676 <tr class="layout">
1677 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1678 <td class="left">12x10 array of single precision floating point values.</td>
1679 </tr>
1680 <tr class="layout">
1681 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1682 <td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1683 </tr>
1684</table>
1685
Dan Gohman87ec5ad2009-11-09 19:01:53 +0000[diff] [blame]1686<p>There is no restriction on indexing beyond the end of the array implied by
1687 a static type (though there are restrictions on indexing beyond the bounds
1688 of an allocated object in some cases). This means that single-dimension
1689 'variable sized array' addressing can be implemented in LLVM with a zero
1690 length array type. An implementation of 'pascal style arrays' in LLVM could
1691 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1692
1693</div>
1694
1695<!-- _______________________________________________________________________ -->
1696<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1697
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1698<div class="doc_text">
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1699
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1700<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1701<p>The function type can be thought of as a function signature. It consists of
1702 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]1703 function type is a scalar type, a void type, a struct type, or a union
1704 type. If the return type is a struct type then all struct elements must be
1705 of first class types, and the struct must have at least one element.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1706
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1707<h5>Syntax:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1708<pre>
Nick Lewycky3b3b54d2009-09-27 07:55:32 +0000[diff] [blame]1709 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1710</pre>
1711
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1712<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]1713 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1714 which indicates that the function takes a variable number of arguments.
1715 Variable argument functions can access their arguments with
1716 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner553fb1e2010-03-02 06:36:51 +0000[diff] [blame]1717 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewyckyeb021882009-09-27 23:27:42 +0000[diff] [blame]1718 <a href="#t_label">label</a>.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1719
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1720<h5>Examples:</h5>
1721<table class="layout">
1722 <tr class="layout">
1723 <td class="left"><tt>i32 (i32)</tt></td>
1724 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
1725 </td>
1726 </tr><tr class="layout">
Chris Lattner553fb1e2010-03-02 06:36:51 +0000[diff] [blame]1727 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1728 </tt></td>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1729 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner553fb1e2010-03-02 06:36:51 +0000[diff] [blame]1730 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
1731 returning <tt>float</tt>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1732 </td>
1733 </tr><tr class="layout">
1734 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1735 <td class="left">A vararg function that takes at least one
1736 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1737 which returns an integer. This is the signature for <tt>printf</tt> in
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1738 LLVM.
1739 </td>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1740 </tr><tr class="layout">
1741 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky3b3b54d2009-09-27 07:55:32 +0000[diff] [blame]1742 <td class="left">A function taking an <tt>i32</tt>, returning a
1743 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1744 </td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1745 </tr>
1746</table>
1747
1748</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1749
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1750<!-- _______________________________________________________________________ -->
1751<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1752
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1753<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1754
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1755<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1756<p>The structure type is used to represent a collection of data members together
1757 in memory. The packing of the field types is defined to match the ABI of the
1758 underlying processor. The elements of a structure may be any type that has a
1759 size.</p>
1760
Jeffrey Yasskine05d7732010-01-11 19:19:26 +0000[diff] [blame]1761<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
1762 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
1763 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1764 Structures in registers are accessed using the
1765 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
1766 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1767<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1768<pre>
1769 { &lt;type list&gt; }
1770</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1771
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1772<h5>Examples:</h5>
1773<table class="layout">
1774 <tr class="layout">
1775 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1776 <td class="left">A triple of three <tt>i32</tt> values</td>
1777 </tr><tr class="layout">
1778 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1779 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1780 second element is a <a href="#t_pointer">pointer</a> to a
1781 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1782 an <tt>i32</tt>.</td>
1783 </tr>
1784</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1785
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1786</div>
1787
1788<!-- _______________________________________________________________________ -->
1789<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1790</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1791
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1792<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1793
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1794<h5>Overview:</h5>
1795<p>The packed structure type is used to represent a collection of data members
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1796 together in memory. There is no padding between fields. Further, the
1797 alignment of a packed structure is 1 byte. The elements of a packed
1798 structure may be any type that has a size.</p>
1799
1800<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1801 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1802 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1803
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1804<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1805<pre>
1806 &lt; { &lt;type list&gt; } &gt;
1807</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1808
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1809<h5>Examples:</h5>
1810<table class="layout">
1811 <tr class="layout">
1812 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1813 <td class="left">A triple of three <tt>i32</tt> values</td>
1814 </tr><tr class="layout">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1815 <td class="left">
1816<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1817 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1818 second element is a <a href="#t_pointer">pointer</a> to a
1819 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1820 an <tt>i32</tt>.</td>
1821 </tr>
1822</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1823
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1824</div>
1825
1826<!-- _______________________________________________________________________ -->
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1827<div class="doc_subsubsection"> <a name="t_union">Union Type</a> </div>
1828
1829<div class="doc_text">
1830
1831<h5>Overview:</h5>
1832<p>A union type describes an object with size and alignment suitable for
1833 an object of any one of a given set of types (also known as an "untagged"
1834 union). It is similar in concept and usage to a
1835 <a href="#t_struct">struct</a>, except that all members of the union
1836 have an offset of zero. The elements of a union may be any type that has a
1837 size. Unions must have at least one member - empty unions are not allowed.
1838 </p>
1839
1840<p>The size of the union as a whole will be the size of its largest member,
1841 and the alignment requirements of the union as a whole will be the largest
1842 alignment requirement of any member.</p>
1843
Dan Gohmanef8400c2010-02-25 16:51:31 +0000[diff] [blame]1844<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]1845 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1846 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1847 Since all members are at offset zero, the getelementptr instruction does
1848 not affect the address, only the type of the resulting pointer.</p>
1849
1850<h5>Syntax:</h5>
1851<pre>
1852 union { &lt;type list&gt; }
1853</pre>
1854
1855<h5>Examples:</h5>
1856<table class="layout">
1857 <tr class="layout">
1858 <td class="left"><tt>union { i32, i32*, float }</tt></td>
1859 <td class="left">A union of three types: an <tt>i32</tt>, a pointer to
1860 an <tt>i32</tt>, and a <tt>float</tt>.</td>
1861 </tr><tr class="layout">
1862 <td class="left">
1863 <tt>union {&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1864 <td class="left">A union, where the first element is a <tt>float</tt> and the
1865 second element is a <a href="#t_pointer">pointer</a> to a
1866 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1867 an <tt>i32</tt>.</td>
1868 </tr>
1869</table>
1870
1871</div>
1872
1873<!-- _______________________________________________________________________ -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1874<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1875
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1876<div class="doc_text">
1877
1878<h5>Overview:</h5>
Dan Gohmanb2f72c82010-02-25 16:50:07 +0000[diff] [blame]1879<p>The pointer type is used to specify memory locations.
1880 Pointers are commonly used to reference objects in memory.</p>
1881
1882<p>Pointer types may have an optional address space attribute defining the
1883 numbered address space where the pointed-to object resides. The default
1884 address space is number zero. The semantics of non-zero address
1885 spaces are target-specific.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1886
1887<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1888 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1889
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1890<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1891<pre>
1892 &lt;type&gt; *
1893</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1894
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1895<h5>Examples:</h5>
1896<table class="layout">
1897 <tr class="layout">
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]1898 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1899 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1900 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1901 </tr>
1902 <tr class="layout">
1903 <td class="left"><tt>i32 (i32 *) *</tt></td>
1904 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1905 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1906 <tt>i32</tt>.</td>
1907 </tr>
1908 <tr class="layout">
1909 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1910 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1911 that resides in address space #5.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1912 </tr>
1913</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1914
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1915</div>
1916
1917<!-- _______________________________________________________________________ -->
1918<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1919
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1920<div class="doc_text">
1921
1922<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1923<p>A vector type is a simple derived type that represents a vector of elements.
1924 Vector types are used when multiple primitive data are operated in parallel
1925 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sands87598b02009-11-27 13:38:03 +0000[diff] [blame]1926 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1927 <a href="#t_firstclass">first class</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1928
1929<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1930<pre>
1931 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1932</pre>
1933
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1934<p>The number of elements is a constant integer value; elementtype may be any
1935 integer or floating point type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1936
1937<h5>Examples:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1938<table class="layout">
1939 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1940 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1941 <td class="left">Vector of 4 32-bit integer values.</td>
1942 </tr>
1943 <tr class="layout">
1944 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1945 <td class="left">Vector of 8 32-bit floating-point values.</td>
1946 </tr>
1947 <tr class="layout">
1948 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1949 <td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1950 </tr>
1951</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1952
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1953</div>
1954
1955<!-- _______________________________________________________________________ -->
1956<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1957<div class="doc_text">
1958
1959<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1960<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1961 corresponds (for example) to the C notion of a forward declared structure
1962 type. In LLVM, opaque types can eventually be resolved to any type (not just
1963 a structure type).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1964
1965<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1966<pre>
1967 opaque
1968</pre>
1969
1970<h5>Examples:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1971<table class="layout">
1972 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1973 <td class="left"><tt>opaque</tt></td>
1974 <td class="left">An opaque type.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1975 </tr>
1976</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1977
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1978</div>
1979
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1980<!-- ======================================================================= -->
1981<div class="doc_subsection">
1982 <a name="t_uprefs">Type Up-references</a>
1983</div>
1984
1985<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1986
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1987<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1988<p>An "up reference" allows you to refer to a lexically enclosing type without
1989 requiring it to have a name. For instance, a structure declaration may
1990 contain a pointer to any of the types it is lexically a member of. Example
1991 of up references (with their equivalent as named type declarations)
1992 include:</p>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1993
1994<pre>
Chris Lattner5ad632d2009-02-09 10:00:56 +0000[diff] [blame]1995 { \2 * } %x = type { %x* }
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1996 { \2 }* %y = type { %y }*
1997 \1* %z = type %z*
1998</pre>
1999
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2000<p>An up reference is needed by the asmprinter for printing out cyclic types
2001 when there is no declared name for a type in the cycle. Because the
2002 asmprinter does not want to print out an infinite type string, it needs a
2003 syntax to handle recursive types that have no names (all names are optional
2004 in llvm IR).</p>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]2005
2006<h5>Syntax:</h5>
2007<pre>
2008 \&lt;level&gt;
2009</pre>
2010
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2011<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]2012
2013<h5>Examples:</h5>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]2014<table class="layout">
2015 <tr class="layout">
2016 <td class="left"><tt>\1*</tt></td>
2017 <td class="left">Self-referential pointer.</td>
2018 </tr>
2019 <tr class="layout">
2020 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
2021 <td class="left">Recursive structure where the upref refers to the out-most
2022 structure.</td>
2023 </tr>
2024</table>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]2025
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2026</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2027
2028<!-- *********************************************************************** -->
2029<div class="doc_section"> <a name="constants">Constants</a> </div>
2030<!-- *********************************************************************** -->
2031
2032<div class="doc_text">
2033
2034<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2035 them all and their syntax.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2036
2037</div>
2038
2039<!-- ======================================================================= -->
2040<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
2041
2042<div class="doc_text">
2043
2044<dl>
2045 <dt><b>Boolean constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2046 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]2047 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2048
2049 <dt><b>Integer constants</b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2050 <dd>Standard integers (such as '4') are constants of
2051 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2052 with integer types.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2053
2054 <dt><b>Floating point constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2055 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2056 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2057 notation (see below). The assembler requires the exact decimal value of a
2058 floating-point constant. For example, the assembler accepts 1.25 but
2059 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2060 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2061
2062 <dt><b>Null pointer constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2063 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2064 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2065</dl>
2066
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2067<p>The one non-intuitive notation for constants is the hexadecimal form of
2068 floating point constants. For example, the form '<tt>double
2069 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2070 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2071 constants are required (and the only time that they are generated by the
2072 disassembler) is when a floating point constant must be emitted but it cannot
2073 be represented as a decimal floating point number in a reasonable number of
2074 digits. For example, NaN's, infinities, and other special values are
2075 represented in their IEEE hexadecimal format so that assembly and disassembly
2076 do not cause any bits to change in the constants.</p>
2077
Dale Johannesenf82a52f2009-02-11 22:14:51 +0000[diff] [blame]2078<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2079 represented using the 16-digit form shown above (which matches the IEEE754
2080 representation for double); float values must, however, be exactly
2081 representable as IEE754 single precision. Hexadecimal format is always used
2082 for long double, and there are three forms of long double. The 80-bit format
2083 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2084 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2085 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2086 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2087 currently supported target uses this format. Long doubles will only work if
2088 they match the long double format on your target. All hexadecimal formats
2089 are big-endian (sign bit at the left).</p>
2090
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2091</div>
2092
2093<!-- ======================================================================= -->
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]2094<div class="doc_subsection">
Bill Wendling1a2630a2009-07-20 02:32:41 +0000[diff] [blame]2095<a name="aggregateconstants"></a> <!-- old anchor -->
2096<a name="complexconstants">Complex Constants</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2097</div>
2098
2099<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2100
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]2101<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2102 constants and smaller complex constants.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2103
2104<dl>
2105 <dt><b>Structure constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2106 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2107 type definitions (a comma separated list of elements, surrounded by braces
2108 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2109 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2110 Structure constants must have <a href="#t_struct">structure type</a>, and
2111 the number and types of elements must match those specified by the
2112 type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2113
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]2114 <dt><b>Union constants</b></dt>
2115 <dd>Union constants are represented with notation similar to a structure with
2116 a single element - that is, a single typed element surrounded
2117 by braces (<tt>{}</tt>)). For example: "<tt>{ i32 4 }</tt>". The
2118 <a href="#t_union">union type</a> can be initialized with a single-element
2119 struct as long as the type of the struct element matches the type of
2120 one of the union members.</dd>
2121
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2122 <dt><b>Array constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2123 <dd>Array constants are represented with notation similar to array type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2124 definitions (a comma separated list of elements, surrounded by square
2125 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2126 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2127 the number and types of elements must match those specified by the
2128 type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2129
2130 <dt><b>Vector constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2131 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2132 definitions (a comma separated list of elements, surrounded by
2133 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2134 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2135 have <a href="#t_vector">vector type</a>, and the number and types of
2136 elements must match those specified by the type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2137
2138 <dt><b>Zero initialization</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2139 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]2140 value to zero of <em>any</em> type, including scalar and
2141 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2142 This is often used to avoid having to print large zero initializers
2143 (e.g. for large arrays) and is always exactly equivalent to using explicit
2144 zero initializers.</dd>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2145
2146 <dt><b>Metadata node</b></dt>
Nick Lewyckyf122c7e2009-05-30 16:08:30 +0000[diff] [blame]2147 <dd>A metadata node is a structure-like constant with
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2148 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2149 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2150 be interpreted as part of the instruction stream, metadata is a place to
2151 attach additional information such as debug info.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2152</dl>
2153
2154</div>
2155
2156<!-- ======================================================================= -->
2157<div class="doc_subsection">
2158 <a name="globalconstants">Global Variable and Function Addresses</a>
2159</div>
2160
2161<div class="doc_text">
2162
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2163<p>The addresses of <a href="#globalvars">global variables</a>
2164 and <a href="#functionstructure">functions</a> are always implicitly valid
2165 (link-time) constants. These constants are explicitly referenced when
2166 the <a href="#identifiers">identifier for the global</a> is used and always
2167 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2168 legal LLVM file:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2169
2170<div class="doc_code">
2171<pre>
2172@X = global i32 17
2173@Y = global i32 42
2174@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
2175</pre>
2176</div>
2177
2178</div>
2179
2180<!-- ======================================================================= -->
2181<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
2182<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2183
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2184<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]2185 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2186 Undefined values may be of any type (other than label or void) and be used
2187 anywhere a constant is permitted.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2188
Chris Lattner9d1e4fa2009-09-11 01:49:31 +0000[diff] [blame]2189<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2190 program is well defined no matter what value is used. This gives the
2191 compiler more freedom to optimize. Here are some examples of (potentially
2192 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2193
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2194
2195<div class="doc_code">
2196<pre>
2197 %A = add %X, undef
2198 %B = sub %X, undef
2199 %C = xor %X, undef
2200Safe:
2201 %A = undef
2202 %B = undef
2203 %C = undef
2204</pre>
2205</div>
2206
2207<p>This is safe because all of the output bits are affected by the undef bits.
2208Any output bit can have a zero or one depending on the input bits.</p>
2209
2210<div class="doc_code">
2211<pre>
2212 %A = or %X, undef
2213 %B = and %X, undef
2214Safe:
2215 %A = -1
2216 %B = 0
2217Unsafe:
2218 %A = undef
2219 %B = undef
2220</pre>
2221</div>
2222
2223<p>These logical operations have bits that are not always affected by the input.
2224For example, if "%X" has a zero bit, then the output of the 'and' operation will
2225always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattner9d1e4fa2009-09-11 01:49:31 +0000[diff] [blame]2226such, 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]2227However, it is safe to assume that all bits of the undef could be 0, and
2228optimize the and to 0. Likewise, it is safe to assume that all the bits of
2229the 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]2230-1.</p>
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2231
2232<div class="doc_code">
2233<pre>
2234 %A = select undef, %X, %Y
2235 %B = select undef, 42, %Y
2236 %C = select %X, %Y, undef
2237Safe:
2238 %A = %X (or %Y)
2239 %B = 42 (or %Y)
2240 %C = %Y
2241Unsafe:
2242 %A = undef
2243 %B = undef
2244 %C = undef
2245</pre>
2246</div>
2247
2248<p>This set of examples show that undefined select (and conditional branch)
2249conditions can go "either way" but they have to come from one of the two
2250operands. In the %A example, if %X and %Y were both known to have a clear low
2251bit, then %A would have to have a cleared low bit. However, in the %C example,
2252the optimizer is allowed to assume that the undef operand could be the same as
2253%Y, allowing the whole select to be eliminated.</p>
2254
2255
2256<div class="doc_code">
2257<pre>
2258 %A = xor undef, undef
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2259
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2260 %B = undef
2261 %C = xor %B, %B
2262
2263 %D = undef
2264 %E = icmp lt %D, 4
2265 %F = icmp gte %D, 4
2266
2267Safe:
2268 %A = undef
2269 %B = undef
2270 %C = undef
2271 %D = undef
2272 %E = undef
2273 %F = undef
2274</pre>
2275</div>
2276
2277<p>This example points out that two undef operands are not necessarily the same.
2278This can be surprising to people (and also matches C semantics) where they
2279assume that "X^X" is always zero, even if X is undef. This isn't true for a
2280number of reasons, but the short answer is that an undef "variable" can
2281arbitrarily change its value over its "live range". This is true because the
2282"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2283logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2284so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattnerc802e482009-09-08 15:13:16 +0000[diff] [blame]2285to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2286would not hold.</p>
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2287
2288<div class="doc_code">
2289<pre>
2290 %A = fdiv undef, %X
2291 %B = fdiv %X, undef
2292Safe:
2293 %A = undef
2294b: unreachable
2295</pre>
2296</div>
2297
2298<p>These examples show the crucial difference between an <em>undefined
2299value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2300allowed to have an arbitrary bit-pattern. This means that the %A operation
2301can be constant folded to undef because the undef could be an SNaN, and fdiv is
2302not (currently) defined on SNaN's. However, in the second example, we can make
2303a more aggressive assumption: because the undef is allowed to be an arbitrary
2304value, 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]2305has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2306does not execute at all. This allows us to delete the divide and all code after
2307it: since the undefined operation "can't happen", the optimizer can assume that
2308it occurs in dead code.
2309</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2310
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2311<div class="doc_code">
2312<pre>
2313a: store undef -> %X
2314b: store %X -> undef
2315Safe:
2316a: &lt;deleted&gt;
2317b: unreachable
2318</pre>
2319</div>
2320
2321<p>These examples reiterate the fdiv example: a store "of" an undefined value
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2322can be assumed to not have any effect: we can assume that the value is
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2323overwritten with bits that happen to match what was already there. However, a
2324store "to" an undefined location could clobber arbitrary memory, therefore, it
2325has undefined behavior.</p>
2326
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2327</div>
2328
2329<!-- ======================================================================= -->
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]2330<div class="doc_subsection"><a name="trapvalues">Trap Values</a></div>
2331<div class="doc_text">
2332
Dan Gohman67bf37f2010-04-26 20:21:21 +0000[diff] [blame]2333<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]2334 instead of representing an unspecified bit pattern, they represent the
2335 fact that an instruction or constant expression which cannot evoke side
2336 effects has nevertheless detected a condition which results in undefined
Dan Gohman67bf37f2010-04-26 20:21:21 +0000[diff] [blame]2337 behavior.</p>
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]2338
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2339<p>There is currently no way of representing a trap value in the IR; they
Dan Gohmanc4bfe502010-05-03 14:51:43 +0000[diff] [blame]2340 only exist when produced by operations such as
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2341 <a href="#i_add"><tt>add</tt></a> with the <tt>nsw</tt> flag.</p>
Dan Gohman568ca042010-04-26 23:36:52 +0000[diff] [blame]2342
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2343<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohman568ca042010-04-26 23:36:52 +0000[diff] [blame]2344
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2345<p>
2346<ul>
2347<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2348 their operands.</li>
2349
2350<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2351 to their dynamic predecessor basic block.</li>
2352
2353<li>Function arguments depend on the corresponding actual argument values in
2354 the dynamic callers of their functions.</li>
2355
2356<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2357 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2358 control back to them.</li>
2359
Dan Gohman5e7b8fb2010-05-03 14:55:22 +0000[diff] [blame^]2360<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
2361 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_unwind"><tt>unwind</tt></a>,
2362 or exception-throwing call instructions that dynamically transfer control
2363 back to them.</li>
2364
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2365<li>Non-volatile loads and stores depend on the most recent stores to all of the
2366 referenced memory addresses, following the order in the IR
2367 (including loads and stores implied by intrinsics such as
2368 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2369
2370<!-- FIXME: padding in the middle of a struct -->
2371
2372<!-- TODO: In the case of multiple threads, this only applies to loads and
2373 stores from the same thread as the store, or which are sequenced after the
Dan Gohman568ca042010-04-26 23:36:52 +0000[diff] [blame]2374 store by synchronization. -->
2375
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2376<!-- TODO: floating-point exception state -->
Dan Gohman568ca042010-04-26 23:36:52 +0000[diff] [blame]2377
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2378<li>An instruction with externally visible side effects depends on the most
2379 recent preceding instruction with externally visible side effects, following
2380 the order in the IR. (This includes volatile loads and stores.)</li>
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]2381
Dan Gohman5e7b8fb2010-05-03 14:55:22 +0000[diff] [blame^]2382<li>An instruction <i>control-depends</i> on a
2383 <a href="#terminators">terminator instruction</a>
2384 if the terminator instruction has multiple successors and the instruction
2385 is always executed when control transfers to one of the successors, and
2386 may not be executed when control is transfered to another.</li>
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2387
2388<li>Dependence is transitive.</li>
2389
2390</ul>
2391</p>
2392
2393<p>Whenever a trap value is generated, all values which depend on it evaluate
2394 to trap. If they have side effects, the evoke their side effects as if each
2395 operand with a trap value were undef. If they have externally-visible side
2396 effects, the behavior is undefined.</p>
2397
2398<p>Here are some examples:</p>
Dan Gohman54884272010-04-26 20:54:53 +0000[diff] [blame]2399
Dan Gohman568ca042010-04-26 23:36:52 +0000[diff] [blame]2400<div class="doc_code">
2401<pre>
2402entry:
2403 %trap = sub nuw i32 0, 1 ; Results in a trap value.
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2404 %still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2405 %trap_yet_again = getelementptr i32* @h, i32 %still_trap
2406 store i32 0, i32* %trap_yet_again ; undefined behavior
2407
2408 store i32 %trap, i32* @g ; Trap value conceptually stored to memory.
2409 %trap2 = load i32* @g ; Returns a trap value, not just undef.
2410
2411 volatile store i32 %trap, i32* @g ; External observation; undefined behavior.
2412
2413 %narrowaddr = bitcast i32* @g to i16*
2414 %wideaddr = bitcast i32* @g to i64*
2415 %trap3 = load 16* %narrowaddr ; Returns a trap value.
2416 %trap4 = load i64* %widaddr ; Returns a trap value.
2417
2418 %cmp = icmp i32 slt %trap, 0 ; Returns a trap value.
Dan Gohman568ca042010-04-26 23:36:52 +0000[diff] [blame]2419 %br i1 %cmp, %true, %end ; Branch to either destination.
2420
2421true:
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2422 volatile store i32 0, i32* @g ; This is control-dependent on %cmp, so
2423 ; it has undefined behavior.
Dan Gohman568ca042010-04-26 23:36:52 +0000[diff] [blame]2424 br label %end
2425
2426end:
2427 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2428 ; Both edges into this PHI are
2429 ; control-dependent on %cmp, so this
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2430 ; always results in a trap value.
Dan Gohman568ca042010-04-26 23:36:52 +0000[diff] [blame]2431
2432 volatile store i32 0, i32* @g ; %end is control-equivalent to %entry
2433 ; so this is defined (ignoring earlier
2434 ; undefined behavior in this example).
Dan Gohman568ca042010-04-26 23:36:52 +0000[diff] [blame]2435</pre>
2436</div>
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]2437
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]2438</div>
2439
2440<!-- ======================================================================= -->
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]2441<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2442 Blocks</a></div>
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2443<div class="doc_text">
2444
Chris Lattner620cead2009-11-01 01:27:45 +0000[diff] [blame]2445<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2446
2447<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner24f2e852009-10-27 21:49:40 +0000[diff] [blame]2448 basic block in the specified function, and always has an i8* type. Taking
Chris Lattner620cead2009-11-01 01:27:45 +0000[diff] [blame]2449 the address of the entry block is illegal.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2450
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2451<p>This value only has defined behavior when used as an operand to the
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2452 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2453 against null. Pointer equality tests between labels addresses is undefined
2454 behavior - though, again, comparison against null is ok, and no label is
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]2455 equal to the null pointer. This may also be passed around as an opaque
2456 pointer sized value as long as the bits are not inspected. This allows
Chris Lattner0bae7b32009-10-27 21:44:20 +0000[diff] [blame]2457 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2458 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2459
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]2460<p>Finally, some targets may provide defined semantics when
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2461 using the value as the operand to an inline assembly, but that is target
2462 specific.
2463 </p>
2464
2465</div>
2466
2467
2468<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2469<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2470</div>
2471
2472<div class="doc_text">
2473
2474<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2475 to be used as constants. Constant expressions may be of
2476 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2477 operation that does not have side effects (e.g. load and call are not
2478 supported). The following is the syntax for constant expressions:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2479
2480<dl>
2481 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2482 <dd>Truncate a constant to another type. The bit size of CST must be larger
2483 than the bit size of TYPE. Both types must be integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2484
2485 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2486 <dd>Zero extend a constant to another type. The bit size of CST must be
2487 smaller or equal to the bit size of TYPE. Both types must be
2488 integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2489
2490 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2491 <dd>Sign extend a constant to another type. The bit size of CST must be
2492 smaller or equal to the bit size of TYPE. Both types must be
2493 integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2494
2495 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2496 <dd>Truncate a floating point constant to another floating point type. The
2497 size of CST must be larger than the size of TYPE. Both types must be
2498 floating point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2499
2500 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2501 <dd>Floating point extend a constant to another type. The size of CST must be
2502 smaller or equal to the size of TYPE. Both types must be floating
2503 point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2504
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]2505 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2506 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2507 constant. TYPE must be a scalar or vector integer type. CST must be of
2508 scalar or vector floating point type. Both CST and TYPE must be scalars,
2509 or vectors of the same number of elements. If the value won't fit in the
2510 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2511
2512 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
2513 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2514 constant. TYPE must be a scalar or vector integer type. CST must be of
2515 scalar or vector floating point type. Both CST and TYPE must be scalars,
2516 or vectors of the same number of elements. If the value won't fit in the
2517 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2518
2519 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
2520 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2521 constant. TYPE must be a scalar or vector floating point type. CST must be
2522 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2523 vectors of the same number of elements. If the value won't fit in the
2524 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2525
2526 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
2527 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2528 constant. TYPE must be a scalar or vector floating point type. CST must be
2529 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2530 vectors of the same number of elements. If the value won't fit in the
2531 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2532
2533 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2534 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2535 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2536 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2537 make it fit in <tt>TYPE</tt>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2538
2539 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2540 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2541 type. CST must be of integer type. The CST value is zero extended,
2542 truncated, or unchanged to make it fit in a pointer size. This one is
2543 <i>really</i> dangerous!</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2544
2545 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner557bc5d2009-02-28 18:27:03 +0000[diff] [blame]2546 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2547 are the same as those for the <a href="#i_bitcast">bitcast
2548 instruction</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2549
2550 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]2551 <dt><b><tt>getelementptr inbounds ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2552 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2553 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2554 instruction, the index list may have zero or more indexes, which are
2555 required to make sense for the type of "CSTPTR".</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2556
2557 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2558 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2559
2560 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2561 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2562
2563 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2564 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
2565
2566 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2567 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2568 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2569
2570 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2571 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2572 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2573
2574 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2575 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2576 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2577
2578 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2579 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2580 be any of the <a href="#binaryops">binary</a>
2581 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2582 on operands are the same as those for the corresponding instruction
2583 (e.g. no bitwise operations on floating point values are allowed).</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2584</dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2585
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2586</div>
2587
2588<!-- *********************************************************************** -->
2589<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2590<!-- *********************************************************************** -->
2591
2592<!-- ======================================================================= -->
2593<div class="doc_subsection">
2594<a name="inlineasm">Inline Assembler Expressions</a>
2595</div>
2596
2597<div class="doc_text">
2598
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2599<p>LLVM supports inline assembler expressions (as opposed
2600 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2601 a special value. This value represents the inline assembler as a string
2602 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2603 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2604 expression has side effects, and a flag indicating whether the function
2605 containing the asm needs to align its stack conservatively. An example
2606 inline assembler expression is:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2607
2608<div class="doc_code">
2609<pre>
2610i32 (i32) asm "bswap $0", "=r,r"
2611</pre>
2612</div>
2613
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2614<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2615 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2616 have:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2617
2618<div class="doc_code">
2619<pre>
2620%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
2621</pre>
2622</div>
2623
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2624<p>Inline asms with side effects not visible in the constraint list must be
2625 marked as having side effects. This is done through the use of the
2626 '<tt>sideeffect</tt>' keyword, like so:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2627
2628<div class="doc_code">
2629<pre>
2630call void asm sideeffect "eieio", ""()
2631</pre>
2632</div>
2633
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2634<p>In some cases inline asms will contain code that will not work unless the
2635 stack is aligned in some way, such as calls or SSE instructions on x86,
2636 yet will not contain code that does that alignment within the asm.
2637 The compiler should make conservative assumptions about what the asm might
2638 contain and should generate its usual stack alignment code in the prologue
2639 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2640
2641<div class="doc_code">
2642<pre>
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2643call void asm alignstack "eieio", ""()
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2644</pre>
2645</div>
2646
2647<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2648 first.</p>
2649
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2650<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2651 documented here. Constraints on what can be done (e.g. duplication, moving,
2652 etc need to be documented). This is probably best done by reference to
2653 another document that covers inline asm from a holistic perspective.</p>
Chris Lattnerbafc8372010-04-07 05:38:05 +0000[diff] [blame]2654</div>
2655
2656<div class="doc_subsubsection">
2657<a name="inlineasm_md">Inline Asm Metadata</a>
2658</div>
2659
2660<div class="doc_text">
2661
2662<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
2663 attached to it that contains a constant integer. If present, the code
2664 generator will use the integer as the location cookie value when report
2665 errors through the LLVMContext error reporting mechanisms. This allows a
Dan Gohmanfde3cd72010-04-28 00:36:01 +0000[diff] [blame]2666 front-end to correlate backend errors that occur with inline asm back to the
Chris Lattnerbafc8372010-04-07 05:38:05 +0000[diff] [blame]2667 source code that produced it. For example:</p>
2668
2669<div class="doc_code">
2670<pre>
2671call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2672...
2673!42 = !{ i32 1234567 }
2674</pre>
2675</div>
2676
2677<p>It is up to the front-end to make sense of the magic numbers it places in the
2678 IR.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2679
2680</div>
2681
Chris Lattnerd0d96292010-01-15 21:50:19 +0000[diff] [blame]2682<!-- ======================================================================= -->
2683<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
2684 Strings</a>
2685</div>
2686
2687<div class="doc_text">
2688
2689<p>LLVM IR allows metadata to be attached to instructions in the program that
2690 can convey extra information about the code to the optimizers and code
2691 generator. One example application of metadata is source-level debug
2692 information. There are two metadata primitives: strings and nodes. All
2693 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2694 preceding exclamation point ('<tt>!</tt>').</p>
2695
2696<p>A metadata string is a string surrounded by double quotes. It can contain
2697 any character by escaping non-printable characters with "\xx" where "xx" is
2698 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2699
2700<p>Metadata nodes are represented with notation similar to structure constants
2701 (a comma separated list of elements, surrounded by braces and preceded by an
2702 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2703 10}</tt>". Metadata nodes can have any values as their operand.</p>
2704
2705<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2706 metadata nodes, which can be looked up in the module symbol table. For
2707 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2708
Devang Patelb1586922010-03-04 23:44:48 +0000[diff] [blame]2709<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
2710 function is using two metadata arguments.
2711
2712 <div class="doc_code">
2713 <pre>
2714 call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2715 </pre>
2716 </div></p>
2717
2718<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
2719 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.
2720
2721 <div class="doc_code">
2722 <pre>
2723 %indvar.next = add i64 %indvar, 1, !dbg !21
2724 </pre>
2725 </div></p>
Chris Lattnerd0d96292010-01-15 21:50:19 +0000[diff] [blame]2726</div>
2727
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2728
2729<!-- *********************************************************************** -->
2730<div class="doc_section">
2731 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2732</div>
2733<!-- *********************************************************************** -->
2734
2735<p>LLVM has a number of "magic" global variables that contain data that affect
2736code generation or other IR semantics. These are documented here. All globals
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2737of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2738section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2739by LLVM.</p>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2740
2741<!-- ======================================================================= -->
2742<div class="doc_subsection">
2743<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2744</div>
2745
2746<div class="doc_text">
2747
2748<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2749href="#linkage_appending">appending linkage</a>. This array contains a list of
2750pointers to global variables and functions which may optionally have a pointer
2751cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2752
2753<pre>
2754 @X = global i8 4
2755 @Y = global i32 123
2756
2757 @llvm.used = appending global [2 x i8*] [
2758 i8* @X,
2759 i8* bitcast (i32* @Y to i8*)
2760 ], section "llvm.metadata"
2761</pre>
2762
2763<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2764compiler, assembler, and linker are required to treat the symbol as if there is
2765a reference to the global that it cannot see. For example, if a variable has
2766internal linkage and no references other than that from the <tt>@llvm.used</tt>
2767list, it cannot be deleted. This is commonly used to represent references from
2768inline asms and other things the compiler cannot "see", and corresponds to
2769"attribute((used))" in GNU C.</p>
2770
2771<p>On some targets, the code generator must emit a directive to the assembler or
2772object file to prevent the assembler and linker from molesting the symbol.</p>
2773
2774</div>
2775
2776<!-- ======================================================================= -->
2777<div class="doc_subsection">
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2778<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2779</div>
2780
2781<div class="doc_text">
2782
2783<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2784<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2785touching the symbol. On targets that support it, this allows an intelligent
2786linker to optimize references to the symbol without being impeded as it would be
2787by <tt>@llvm.used</tt>.</p>
2788
2789<p>This is a rare construct that should only be used in rare circumstances, and
2790should not be exposed to source languages.</p>
2791
2792</div>
2793
2794<!-- ======================================================================= -->
2795<div class="doc_subsection">
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2796<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2797</div>
2798
2799<div class="doc_text">
David Chisnall47e8b772010-04-30 19:23:49 +0000[diff] [blame]2800<pre>
2801%0 = type { i32, void ()* }
David Chisnalla07a3c22010-04-30 19:27:35 +0000[diff] [blame]2802@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnall47e8b772010-04-30 19:23:49 +0000[diff] [blame]2803</pre>
2804<p>The <tt>@llvm.global_ctors</tt> array contains a list of constructor functions and associated priorities. The functions referenced by this array will be called in ascending order of priority (i.e. lowest first) when the module is loaded. The order of functions with the same priority is not defined.
2805</p>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2806
2807</div>
2808
2809<!-- ======================================================================= -->
2810<div class="doc_subsection">
2811<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2812</div>
2813
2814<div class="doc_text">
David Chisnall47e8b772010-04-30 19:23:49 +0000[diff] [blame]2815<pre>
2816%0 = type { i32, void ()* }
David Chisnalla07a3c22010-04-30 19:27:35 +0000[diff] [blame]2817@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnall47e8b772010-04-30 19:23:49 +0000[diff] [blame]2818</pre>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2819
David Chisnall47e8b772010-04-30 19:23:49 +0000[diff] [blame]2820<p>The <tt>@llvm.global_dtors</tt> array contains a list of destructor functions and associated priorities. The functions referenced by this array will be called in descending order of priority (i.e. highest first) when the module is loaded. The order of functions with the same priority is not defined.
2821</p>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2822
2823</div>
2824
2825
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2826<!-- *********************************************************************** -->
2827<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2828<!-- *********************************************************************** -->
2829
2830<div class="doc_text">
2831
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2832<p>The LLVM instruction set consists of several different classifications of
2833 instructions: <a href="#terminators">terminator
2834 instructions</a>, <a href="#binaryops">binary instructions</a>,
2835 <a href="#bitwiseops">bitwise binary instructions</a>,
2836 <a href="#memoryops">memory instructions</a>, and
2837 <a href="#otherops">other instructions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2838
2839</div>
2840
2841<!-- ======================================================================= -->
2842<div class="doc_subsection"> <a name="terminators">Terminator
2843Instructions</a> </div>
2844
2845<div class="doc_text">
2846
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2847<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2848 in a program ends with a "Terminator" instruction, which indicates which
2849 block should be executed after the current block is finished. These
2850 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2851 control flow, not values (the one exception being the
2852 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2853
Duncan Sands048d8062010-04-15 20:35:54 +0000[diff] [blame]2854<p>There are seven different terminator instructions: the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2855 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2856 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2857 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendlingb4ae2292009-11-02 00:25:26 +0000[diff] [blame]2858 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2859 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2860 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2861 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2862
2863</div>
2864
2865<!-- _______________________________________________________________________ -->
2866<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2867Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2868
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2869<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2870
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2871<h5>Syntax:</h5>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2872<pre>
2873 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]2874 ret void <i>; Return from void function</i>
2875</pre>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2876
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2877<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2878<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2879 a value) from a function back to the caller.</p>
2880
2881<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2882 value and then causes control flow, and one that just causes control flow to
2883 occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2884
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2885<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2886<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2887 return value. The type of the return value must be a
2888 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2889
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2890<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2891 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2892 value or a return value with a type that does not match its type, or if it
2893 has a void return type and contains a '<tt>ret</tt>' instruction with a
2894 return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2895
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2896<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2897<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2898 the calling function's context. If the caller is a
2899 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2900 instruction after the call. If the caller was an
2901 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2902 the beginning of the "normal" destination block. If the instruction returns
2903 a value, that value shall set the call or invoke instruction's return
2904 value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2905
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2906<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2907<pre>
2908 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2909 ret void <i>; Return from a void function</i>
Bill Wendlingd163e2d2009-02-28 22:12:54 +0000[diff] [blame]2910 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]2911</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2912
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2913</div>
2914<!-- _______________________________________________________________________ -->
2915<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2916
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2917<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2918
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2919<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2920<pre>
2921 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]2922</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2923
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2924<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2925<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2926 different basic block in the current function. There are two forms of this
2927 instruction, corresponding to a conditional branch and an unconditional
2928 branch.</p>
2929
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2930<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2931<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2932 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2933 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2934 target.</p>
2935
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2936<h5>Semantics:</h5>
2937<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2938 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2939 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2940 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2941
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2942<h5>Example:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]2943<pre>
2944Test:
2945 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2946 br i1 %cond, label %IfEqual, label %IfUnequal
2947IfEqual:
2948 <a href="#i_ret">ret</a> i32 1
2949IfUnequal:
2950 <a href="#i_ret">ret</a> i32 0
2951</pre>
2952
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2953</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2954
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2955<!-- _______________________________________________________________________ -->
2956<div class="doc_subsubsection">
2957 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2958</div>
2959
2960<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2961
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2962<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2963<pre>
2964 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2965</pre>
2966
2967<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2968<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]2969 several different places. It is a generalization of the '<tt>br</tt>'
2970 instruction, allowing a branch to occur to one of many possible
2971 destinations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2972
2973<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2974<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2975 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2976 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2977 The table is not allowed to contain duplicate constant entries.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2978
2979<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2980<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2981 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2982 is searched for the given value. If the value is found, control flow is
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2983 transferred to the corresponding destination; otherwise, control flow is
2984 transferred to the default destination.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2985
2986<h5>Implementation:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2987<p>Depending on properties of the target machine and the particular
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2988 <tt>switch</tt> instruction, this instruction may be code generated in
2989 different ways. For example, it could be generated as a series of chained
2990 conditional branches or with a lookup table.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2991
2992<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2993<pre>
2994 <i>; Emulate a conditional br instruction</i>
2995 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2996 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2997
2998 <i>; Emulate an unconditional br instruction</i>
2999 switch i32 0, label %dest [ ]
3000
3001 <i>; Implement a jump table:</i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]3002 switch i32 %val, label %otherwise [ i32 0, label %onzero
3003 i32 1, label %onone
3004 i32 2, label %ontwo ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3005</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3006
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3007</div>
3008
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]3009
3010<!-- _______________________________________________________________________ -->
3011<div class="doc_subsubsection">
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]3012 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]3013</div>
3014
3015<div class="doc_text">
3016
3017<h5>Syntax:</h5>
3018<pre>
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]3019 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]3020</pre>
3021
3022<h5>Overview:</h5>
3023
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]3024<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]3025 within the current function, whose address is specified by
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]3026 "<tt>address</tt>". Address must be derived from a <a
3027 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]3028
3029<h5>Arguments:</h5>
3030
3031<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3032 rest of the arguments indicate the full set of possible destinations that the
3033 address may point to. Blocks are allowed to occur multiple times in the
3034 destination list, though this isn't particularly useful.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3035
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]3036<p>This destination list is required so that dataflow analysis has an accurate
3037 understanding of the CFG.</p>
3038
3039<h5>Semantics:</h5>
3040
3041<p>Control transfers to the block specified in the address argument. All
3042 possible destination blocks must be listed in the label list, otherwise this
3043 instruction has undefined behavior. This implies that jumps to labels
3044 defined in other functions have undefined behavior as well.</p>
3045
3046<h5>Implementation:</h5>
3047
3048<p>This is typically implemented with a jump through a register.</p>
3049
3050<h5>Example:</h5>
3051<pre>
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]3052 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]3053</pre>
3054
3055</div>
3056
3057
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3058<!-- _______________________________________________________________________ -->
3059<div class="doc_subsubsection">
3060 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
3061</div>
3062
3063<div class="doc_text">
3064
3065<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3066<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]3067 &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]3068 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
3069</pre>
3070
3071<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3072<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3073 function, with the possibility of control flow transfer to either the
3074 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3075 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3076 control flow will return to the "normal" label. If the callee (or any
3077 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3078 instruction, control is interrupted and continued at the dynamically nearest
3079 "exception" label.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3080
3081<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3082<p>This instruction requires several arguments:</p>
3083
3084<ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3085 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3086 convention</a> the call should use. If none is specified, the call
3087 defaults to using C calling conventions.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]3088
3089 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3090 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3091 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]3092
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3093 <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]3094 function value being invoked. In most cases, this is a direct function
3095 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3096 off an arbitrary pointer to function value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3097
3098 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3099 function to be invoked. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3100
3101 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner553fb1e2010-03-02 06:36:51 +0000[diff] [blame]3102 signature argument types and parameter attributes. All arguments must be
3103 of <a href="#t_firstclass">first class</a> type. If the function
3104 signature indicates the function accepts a variable number of arguments,
3105 the extra arguments can be specified.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3106
3107 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3108 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3109
3110 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3111 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3112
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]3113 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3114 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3115 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3116</ol>
3117
3118<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3119<p>This instruction is designed to operate as a standard
3120 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3121 primary difference is that it establishes an association with a label, which
3122 is used by the runtime library to unwind the stack.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3123
3124<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3125 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3126 exception. Additionally, this is important for implementation of
3127 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3128
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3129<p>For the purposes of the SSA form, the definition of the value returned by the
3130 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3131 block to the "normal" label. If the callee unwinds then no return value is
3132 available.</p>
Dan Gohman140ba5d2009-05-22 21:47:08 +0000[diff] [blame]3133
Chris Lattner4a91ef42010-01-15 18:08:37 +0000[diff] [blame]3134<p>Note that the code generator does not yet completely support unwind, and
3135that the invoke/unwind semantics are likely to change in future versions.</p>
3136
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3137<h5>Example:</h5>
3138<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]3139 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3140 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]3141 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3142 unwind label %TestCleanup <i>; {i32}:retval set</i>
3143</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3144
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3145</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3146
3147<!-- _______________________________________________________________________ -->
3148
3149<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
3150Instruction</a> </div>
3151
3152<div class="doc_text">
3153
3154<h5>Syntax:</h5>
3155<pre>
3156 unwind
3157</pre>
3158
3159<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3160<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3161 at the first callee in the dynamic call stack which used
3162 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3163 This is primarily used to implement exception handling.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3164
3165<h5>Semantics:</h5>
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3166<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3167 immediately halt. The dynamic call stack is then searched for the
3168 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3169 Once found, execution continues at the "exceptional" destination block
3170 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3171 instruction in the dynamic call chain, undefined behavior results.</p>
3172
Chris Lattner4a91ef42010-01-15 18:08:37 +0000[diff] [blame]3173<p>Note that the code generator does not yet completely support unwind, and
3174that the invoke/unwind semantics are likely to change in future versions.</p>
3175
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3176</div>
3177
3178<!-- _______________________________________________________________________ -->
3179
3180<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
3181Instruction</a> </div>
3182
3183<div class="doc_text">
3184
3185<h5>Syntax:</h5>
3186<pre>
3187 unreachable
3188</pre>
3189
3190<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3191<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3192 instruction is used to inform the optimizer that a particular portion of the
3193 code is not reachable. This can be used to indicate that the code after a
3194 no-return function cannot be reached, and other facts.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3195
3196<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3197<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3198
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3199</div>
3200
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3201<!-- ======================================================================= -->
3202<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3203
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3204<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3205
3206<p>Binary operators are used to do most of the computation in a program. They
3207 require two operands of the same type, execute an operation on them, and
3208 produce a single value. The operands might represent multiple data, as is
3209 the case with the <a href="#t_vector">vector</a> data type. The result value
3210 has the same type as its operands.</p>
3211
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3212<p>There are several different binary operators:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3213
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3214</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3215
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3216<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3217<div class="doc_subsubsection">
3218 <a name="i_add">'<tt>add</tt>' Instruction</a>
3219</div>
3220
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3221<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3222
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3223<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3224<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3225 &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]3226 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3227 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3228 &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]3229</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3230
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3231<h5>Overview:</h5>
3232<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3233
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3234<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3235<p>The two arguments to the '<tt>add</tt>' instruction must
3236 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3237 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3238
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3239<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3240<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3241
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3242<p>If the sum has unsigned overflow, the result returned is the mathematical
3243 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]3244
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3245<p>Because LLVM integers use a two's complement representation, this instruction
3246 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3247
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3248<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3249 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3250 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]3251 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3252 respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3253
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3254<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3255<pre>
3256 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3257</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3258
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3259</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3260
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3261<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3262<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3263 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
3264</div>
3265
3266<div class="doc_text">
3267
3268<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3269<pre>
3270 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3271</pre>
3272
3273<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3274<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3275
3276<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3277<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3278 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3279 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3280
3281<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3282<p>The value produced is the floating point sum of the two operands.</p>
3283
3284<h5>Example:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3285<pre>
3286 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3287</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3288
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3289</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3290
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3291<!-- _______________________________________________________________________ -->
3292<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3293 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3294</div>
3295
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3296<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3297
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3298<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3299<pre>
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3300 &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]3301 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3302 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3303 &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]3304</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3305
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3306<h5>Overview:</h5>
3307<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3308 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3309
3310<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3311 '<tt>neg</tt>' instruction present in most other intermediate
3312 representations.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3313
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3314<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3315<p>The two arguments to the '<tt>sub</tt>' instruction must
3316 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3317 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3318
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3319<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3320<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3321
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3322<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3323 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3324 result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3325
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3326<p>Because LLVM integers use a two's complement representation, this instruction
3327 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3328
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3329<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3330 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3331 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]3332 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3333 respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3334
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3335<h5>Example:</h5>
3336<pre>
3337 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
3338 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
3339</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3340
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3341</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3342
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3343<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3344<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3345 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3346</div>
3347
3348<div class="doc_text">
3349
3350<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3351<pre>
3352 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3353</pre>
3354
3355<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3356<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3357 operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3358
3359<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3360 '<tt>fneg</tt>' instruction present in most other intermediate
3361 representations.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3362
3363<h5>Arguments:</h5>
Bill Wendling1a2630a2009-07-20 02:32:41 +0000[diff] [blame]3364<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3365 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3366 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3367
3368<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3369<p>The value produced is the floating point difference of the two operands.</p>
3370
3371<h5>Example:</h5>
3372<pre>
3373 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3374 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3375</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3376
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3377</div>
3378
3379<!-- _______________________________________________________________________ -->
3380<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3381 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3382</div>
3383
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3384<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3385
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3386<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3387<pre>
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3388 &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]3389 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3390 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3391 &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]3392</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3393
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3394<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3395<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3396
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3397<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3398<p>The two arguments to the '<tt>mul</tt>' instruction must
3399 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3400 integer values. Both arguments must have identical types.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3401
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3402<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3403<p>The value produced is the integer product of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3404
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3405<p>If the result of the multiplication has unsigned overflow, the result
3406 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3407 width of the result.</p>
3408
3409<p>Because LLVM integers use a two's complement representation, and the result
3410 is the same width as the operands, this instruction returns the correct
3411 result for both signed and unsigned integers. If a full product
3412 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3413 be sign-extended or zero-extended as appropriate to the width of the full
3414 product.</p>
3415
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3416<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3417 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3418 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]3419 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3420 respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3421
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3422<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3423<pre>
3424 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3425</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3426
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3427</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3428
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3429<!-- _______________________________________________________________________ -->
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3430<div class="doc_subsubsection">
3431 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3432</div>
3433
3434<div class="doc_text">
3435
3436<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3437<pre>
3438 &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]3439</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3440
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3441<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3442<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3443
3444<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3445<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3446 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3447 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3448
3449<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3450<p>The value produced is the floating point product of the two operands.</p>
3451
3452<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3453<pre>
3454 &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]3455</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3456
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3457</div>
3458
3459<!-- _______________________________________________________________________ -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3460<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3461</a></div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3462
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3463<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3464
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3465<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3466<pre>
3467 &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]3468</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3469
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3470<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3471<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3472
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3473<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3474<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3475 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3476 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3477
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3478<h5>Semantics:</h5>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3479<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3480
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3481<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3482 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3483
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3484<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3485
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3486<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3487<pre>
3488 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3489</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3490
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3491</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3492
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3493<!-- _______________________________________________________________________ -->
3494<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3495</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3496
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3497<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3498
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3499<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3500<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3501 &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]3502 &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]3503</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3504
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3505<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3506<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3507
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3508<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3509<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3510 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3511 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3512
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3513<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3514<p>The value produced is the signed integer quotient of the two operands rounded
3515 towards zero.</p>
3516
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3517<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3518 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3519
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3520<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3521 undefined behavior; this is a rare case, but can occur, for example, by doing
3522 a 32-bit division of -2147483648 by -1.</p>
3523
Dan Gohman67fa48e2009-07-22 00:04:19 +0000[diff] [blame]3524<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohmanf7263862010-04-23 15:23:32 +0000[diff] [blame]3525 <tt>sdiv</tt> is a <a href="#trapvalues">trap value</a> if the result would
3526 be rounded or if overflow would occur.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3527
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3528<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3529<pre>
3530 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3531</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3532
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3533</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3534
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3535<!-- _______________________________________________________________________ -->
3536<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
3537Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3538
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3539<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3540
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3541<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3542<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3543 &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]3544</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3545
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3546<h5>Overview:</h5>
3547<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3548
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3549<h5>Arguments:</h5>
3550<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3551 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3552 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3553
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3554<h5>Semantics:</h5>
3555<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3556
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3557<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3558<pre>
3559 &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]3560</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3561
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3562</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3563
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3564<!-- _______________________________________________________________________ -->
3565<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3566</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3567
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3568<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3569
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3570<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3571<pre>
3572 &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]3573</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3574
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3575<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3576<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3577 division of its two arguments.</p>
3578
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3579<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3580<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3581 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3582 values. Both arguments must have identical types.</p>
3583
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3584<h5>Semantics:</h5>
3585<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3586 This instruction always performs an unsigned division to get the
3587 remainder.</p>
3588
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3589<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3590 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3591
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3592<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3593
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3594<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3595<pre>
3596 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3597</pre>
3598
3599</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3600
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3601<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3602<div class="doc_subsubsection">
3603 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3604</div>
3605
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3606<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3607
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3608<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3609<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3610 &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]3611</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3612
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3613<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3614<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3615 division of its two operands. This instruction can also take
3616 <a href="#t_vector">vector</a> versions of the values in which case the
3617 elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]3618
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3619<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3620<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3621 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3622 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3623
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3624<h5>Semantics:</h5>
3625<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3626 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3627 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3628 a value. For more information about the difference,
3629 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3630 Math Forum</a>. For a table of how this is implemented in various languages,
3631 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3632 Wikipedia: modulo operation</a>.</p>
3633
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3634<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3635 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3636
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3637<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3638 Overflow also leads to undefined behavior; this is a rare case, but can
3639 occur, for example, by taking the remainder of a 32-bit division of
3640 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3641 lets srem be implemented using instructions that return both the result of
3642 the division and the remainder.)</p>
3643
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3644<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3645<pre>
3646 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3647</pre>
3648
3649</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3650
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3651<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3652<div class="doc_subsubsection">
3653 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3654
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3655<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3656
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3657<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3658<pre>
3659 &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]3660</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3661
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3662<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3663<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3664 its two operands.</p>
3665
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3666<h5>Arguments:</h5>
3667<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3668 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3669 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3670
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3671<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3672<p>This instruction returns the <i>remainder</i> of a division. The remainder
3673 has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3674
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3675<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3676<pre>
3677 &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]3678</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3679
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3680</div>
3681
3682<!-- ======================================================================= -->
3683<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3684Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3685
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3686<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3687
3688<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3689 program. They are generally very efficient instructions and can commonly be
3690 strength reduced from other instructions. They require two operands of the
3691 same type, execute an operation on them, and produce a single value. The
3692 resulting value is the same type as its operands.</p>
3693
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3694</div>
3695
3696<!-- _______________________________________________________________________ -->
3697<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3698Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3699
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3700<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3701
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3702<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3703<pre>
3704 &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]3705</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3706
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3707<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3708<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3709 a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3710
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3711<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3712<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3713 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3714 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3715
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3716<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3717<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3718 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3719 is (statically or dynamically) negative or equal to or larger than the number
3720 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3721 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3722 shift amount in <tt>op2</tt>.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3723
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3724<h5>Example:</h5>
3725<pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3726 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3727 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3728 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3729 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3730 &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]3731</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3732
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3733</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3734
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3735<!-- _______________________________________________________________________ -->
3736<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3737Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3738
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3739<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3740
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3741<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3742<pre>
3743 &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]3744</pre>
3745
3746<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3747<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3748 operand shifted to the right a specified number of bits with zero fill.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3749
3750<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3751<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3752 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3753 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3754
3755<h5>Semantics:</h5>
3756<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3757 significant bits of the result will be filled with zero bits after the shift.
3758 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3759 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3760 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3761 shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3762
3763<h5>Example:</h5>
3764<pre>
3765 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3766 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3767 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3768 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3769 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3770 &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]3771</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3772
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3773</div>
3774
3775<!-- _______________________________________________________________________ -->
3776<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3777Instruction</a> </div>
3778<div class="doc_text">
3779
3780<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3781<pre>
3782 &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]3783</pre>
3784
3785<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3786<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3787 operand shifted to the right a specified number of bits with sign
3788 extension.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3789
3790<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3791<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3792 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3793 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3794
3795<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3796<p>This instruction always performs an arithmetic shift right operation, The
3797 most significant bits of the result will be filled with the sign bit
3798 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3799 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3800 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3801 the corresponding shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3802
3803<h5>Example:</h5>
3804<pre>
3805 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3806 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3807 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3808 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3809 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3810 &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]3811</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3812
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3813</div>
3814
3815<!-- _______________________________________________________________________ -->
3816<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3817Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3818
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3819<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3820
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3821<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3822<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3823 &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]3824</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3825
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3826<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3827<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3828 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3829
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3830<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3831<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3832 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3833 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3834
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3835<h5>Semantics:</h5>
3836<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3837
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3838<table border="1" cellspacing="0" cellpadding="4">
3839 <tbody>
3840 <tr>
3841 <td>In0</td>
3842 <td>In1</td>
3843 <td>Out</td>
3844 </tr>
3845 <tr>
3846 <td>0</td>
3847 <td>0</td>
3848 <td>0</td>
3849 </tr>
3850 <tr>
3851 <td>0</td>
3852 <td>1</td>
3853 <td>0</td>
3854 </tr>
3855 <tr>
3856 <td>1</td>
3857 <td>0</td>
3858 <td>0</td>
3859 </tr>
3860 <tr>
3861 <td>1</td>
3862 <td>1</td>
3863 <td>1</td>
3864 </tr>
3865 </tbody>
3866</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3867
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3868<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3869<pre>
3870 &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]3871 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3872 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
3873</pre>
3874</div>
3875<!-- _______________________________________________________________________ -->
3876<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3877
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3878<div class="doc_text">
3879
3880<h5>Syntax:</h5>
3881<pre>
3882 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3883</pre>
3884
3885<h5>Overview:</h5>
3886<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3887 two operands.</p>
3888
3889<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3890<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3891 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3892 values. Both arguments must have identical types.</p>
3893
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3894<h5>Semantics:</h5>
3895<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3896
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3897<table border="1" cellspacing="0" cellpadding="4">
3898 <tbody>
3899 <tr>
3900 <td>In0</td>
3901 <td>In1</td>
3902 <td>Out</td>
3903 </tr>
3904 <tr>
3905 <td>0</td>
3906 <td>0</td>
3907 <td>0</td>
3908 </tr>
3909 <tr>
3910 <td>0</td>
3911 <td>1</td>
3912 <td>1</td>
3913 </tr>
3914 <tr>
3915 <td>1</td>
3916 <td>0</td>
3917 <td>1</td>
3918 </tr>
3919 <tr>
3920 <td>1</td>
3921 <td>1</td>
3922 <td>1</td>
3923 </tr>
3924 </tbody>
3925</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3926
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3927<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3928<pre>
3929 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3930 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3931 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
3932</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3933
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3934</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3935
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3936<!-- _______________________________________________________________________ -->
3937<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3938Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3939
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3940<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3941
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3942<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3943<pre>
3944 &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]3945</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3946
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3947<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3948<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3949 its two operands. The <tt>xor</tt> is used to implement the "one's
3950 complement" operation, which is the "~" operator in C.</p>
3951
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3952<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3953<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3954 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3955 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3956
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3957<h5>Semantics:</h5>
3958<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3959
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3960<table border="1" cellspacing="0" cellpadding="4">
3961 <tbody>
3962 <tr>
3963 <td>In0</td>
3964 <td>In1</td>
3965 <td>Out</td>
3966 </tr>
3967 <tr>
3968 <td>0</td>
3969 <td>0</td>
3970 <td>0</td>
3971 </tr>
3972 <tr>
3973 <td>0</td>
3974 <td>1</td>
3975 <td>1</td>
3976 </tr>
3977 <tr>
3978 <td>1</td>
3979 <td>0</td>
3980 <td>1</td>
3981 </tr>
3982 <tr>
3983 <td>1</td>
3984 <td>1</td>
3985 <td>0</td>
3986 </tr>
3987 </tbody>
3988</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3989
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3990<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3991<pre>
3992 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3993 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3994 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3995 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
3996</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3997
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3998</div>
3999
4000<!-- ======================================================================= -->
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4001<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4002 <a name="vectorops">Vector Operations</a>
4003</div>
4004
4005<div class="doc_text">
4006
4007<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4008 target-independent manner. These instructions cover the element-access and
4009 vector-specific operations needed to process vectors effectively. While LLVM
4010 does directly support these vector operations, many sophisticated algorithms
4011 will want to use target-specific intrinsics to take full advantage of a
4012 specific target.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4013
4014</div>
4015
4016<!-- _______________________________________________________________________ -->
4017<div class="doc_subsubsection">
4018 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
4019</div>
4020
4021<div class="doc_text">
4022
4023<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4024<pre>
4025 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
4026</pre>
4027
4028<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4029<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4030 from a vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4031
4032
4033<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4034<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4035 of <a href="#t_vector">vector</a> type. The second operand is an index
4036 indicating the position from which to extract the element. The index may be
4037 a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4038
4039<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4040<p>The result is a scalar of the same type as the element type of
4041 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4042 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4043 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4044
4045<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4046<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]4047 &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]4048</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4049
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4050</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4051
4052<!-- _______________________________________________________________________ -->
4053<div class="doc_subsubsection">
4054 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
4055</div>
4056
4057<div class="doc_text">
4058
4059<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4060<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]4061 &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]4062</pre>
4063
4064<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4065<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4066 vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4067
4068<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4069<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4070 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4071 whose type must equal the element type of the first operand. The third
4072 operand is an index indicating the position at which to insert the value.
4073 The index may be a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4074
4075<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4076<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4077 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4078 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4079 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4080
4081<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4082<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]4083 &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]4084</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4085
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4086</div>
4087
4088<!-- _______________________________________________________________________ -->
4089<div class="doc_subsubsection">
4090 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
4091</div>
4092
4093<div class="doc_text">
4094
4095<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4096<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]4097 &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]4098</pre>
4099
4100<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4101<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4102 from two input vectors, returning a vector with the same element type as the
4103 input and length that is the same as the shuffle mask.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4104
4105<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4106<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4107 with types that match each other. The third argument is a shuffle mask whose
4108 element type is always 'i32'. The result of the instruction is a vector
4109 whose length is the same as the shuffle mask and whose element type is the
4110 same as the element type of the first two operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4111
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4112<p>The shuffle mask operand is required to be a constant vector with either
4113 constant integer or undef values.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4114
4115<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4116<p>The elements of the two input vectors are numbered from left to right across
4117 both of the vectors. The shuffle mask operand specifies, for each element of
4118 the result vector, which element of the two input vectors the result element
4119 gets. The element selector may be undef (meaning "don't care") and the
4120 second operand may be undef if performing a shuffle from only one vector.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4121
4122<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4123<pre>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4124 &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]4125 &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]4126 &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]4127 &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]4128 &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]4129 &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]4130 &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]4131 &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]4132</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4133
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4134</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4135
4136<!-- ======================================================================= -->
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4137<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4138 <a name="aggregateops">Aggregate Operations</a>
4139</div>
4140
4141<div class="doc_text">
4142
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4143<p>LLVM supports several instructions for working with
4144 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4145
4146</div>
4147
4148<!-- _______________________________________________________________________ -->
4149<div class="doc_subsubsection">
4150 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
4151</div>
4152
4153<div class="doc_text">
4154
4155<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4156<pre>
4157 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4158</pre>
4159
4160<h5>Overview:</h5>
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4161<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4162 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4163
4164<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4165<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4166 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4167 <a href="#t_array">array</a> type. The operands are constant indices to
4168 specify which value to extract in a similar manner as indices in a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4169 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4170
4171<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4172<p>The result is the value at the position in the aggregate specified by the
4173 index operands.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4174
4175<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4176<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]4177 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4178</pre>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4179
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4180</div>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4181
4182<!-- _______________________________________________________________________ -->
4183<div class="doc_subsubsection">
4184 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
4185</div>
4186
4187<div class="doc_text">
4188
4189<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4190<pre>
Jeffrey Yasskine05d7732010-01-11 19:19:26 +0000[diff] [blame]4191 &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]4192</pre>
4193
4194<h5>Overview:</h5>
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4195<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4196 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4197
4198<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4199<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4200 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4201 <a href="#t_array">array</a> type. The second operand is a first-class
4202 value to insert. The following operands are constant indices indicating
4203 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]4204 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
4205 value to insert must have the same type as the value identified by the
4206 indices.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4207
4208<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4209<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4210 that of <tt>val</tt> except that the value at the position specified by the
4211 indices is that of <tt>elt</tt>.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4212
4213<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4214<pre>
Jeffrey Yasskine05d7732010-01-11 19:19:26 +0000[diff] [blame]4215 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4216 %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]4217</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4218
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4219</div>
4220
4221
4222<!-- ======================================================================= -->
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4223<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4224 <a name="memoryops">Memory Access and Addressing Operations</a>
4225</div>
4226
4227<div class="doc_text">
4228
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4229<p>A key design point of an SSA-based representation is how it represents
4230 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]4231 very simple. This section describes how to read, write, and allocate
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4232 memory in LLVM.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4233
4234</div>
4235
4236<!-- _______________________________________________________________________ -->
4237<div class="doc_subsubsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4238 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4239</div>
4240
4241<div class="doc_text">
4242
4243<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4244<pre>
4245 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
4246</pre>
4247
4248<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4249<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4250 currently executing function, to be automatically released when this function
4251 returns to its caller. The object is always allocated in the generic address
4252 space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4253
4254<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4255<p>The '<tt>alloca</tt>' instruction
4256 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4257 runtime stack, returning a pointer of the appropriate type to the program.
4258 If "NumElements" is specified, it is the number of elements allocated,
4259 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4260 specified, the value result of the allocation is guaranteed to be aligned to
4261 at least that boundary. If not specified, or if zero, the target can choose
4262 to align the allocation on any convenient boundary compatible with the
4263 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4264
4265<p>'<tt>type</tt>' may be any sized type.</p>
4266
4267<h5>Semantics:</h5>
Bill Wendling2a454572009-05-08 20:49:29 +0000[diff] [blame]4268<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4269 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4270 memory is automatically released when the function returns. The
4271 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4272 variables that must have an address available. When the function returns
4273 (either with the <tt><a href="#i_ret">ret</a></tt>
4274 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4275 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4276
4277<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4278<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]4279 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4280 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4281 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4282 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4283</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4284
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4285</div>
4286
4287<!-- _______________________________________________________________________ -->
4288<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4289Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4290
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4291<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4292
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4293<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4294<pre>
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4295 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4296 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4297 !&lt;index&gt; = !{ i32 1 }
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4298</pre>
4299
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4300<h5>Overview:</h5>
4301<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4302
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4303<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4304<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4305 from which to load. The pointer must point to
4306 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4307 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin6dc467f2010-04-26 21:21:24 +0000[diff] [blame]4308 number or order of execution of this <tt>load</tt> with other <a
4309 href="#volatile">volatile operations</a>.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4310
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4311<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4312 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]4313 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4314 alignment for the target. It is the responsibility of the code emitter to
4315 ensure that the alignment information is correct. Overestimating the
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4316 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4317 produce less efficient code. An alignment of 1 is always safe.</p>
4318
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4319<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4320 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]4321 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4322 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4323 and code generator that this load is not expected to be reused in the cache.
4324 The code generator may select special instructions to save cache bandwidth,
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]4325 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4326
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4327<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4328<p>The location of memory pointed to is loaded. If the value being loaded is of
4329 scalar type then the number of bytes read does not exceed the minimum number
4330 of bytes needed to hold all bits of the type. For example, loading an
4331 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4332 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4333 is undefined if the value was not originally written using a store of the
4334 same type.</p>
4335
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4336<h5>Examples:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4337<pre>
4338 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4339 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4340 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
4341</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4342
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4343</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4344
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4345<!-- _______________________________________________________________________ -->
4346<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4347Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4348
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4349<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4350
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4351<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4352<pre>
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4353 store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !<index>] <i>; yields {void}</i>
4354 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]4355</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4356
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4357<h5>Overview:</h5>
4358<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4359
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4360<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4361<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4362 and an address at which to store it. The type of the
4363 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4364 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin6dc467f2010-04-26 21:21:24 +0000[diff] [blame]4365 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4366 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4367 order of execution of this <tt>store</tt> with other <a
4368 href="#volatile">volatile operations</a>.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4369
4370<p>The optional constant "align" argument specifies the alignment of the
4371 operation (that is, the alignment of the memory address). A value of 0 or an
4372 omitted "align" argument means that the operation has the preferential
4373 alignment for the target. It is the responsibility of the code emitter to
4374 ensure that the alignment information is correct. Overestimating the
4375 alignment results in an undefined behavior. Underestimating the alignment may
4376 produce less efficient code. An alignment of 1 is always safe.</p>
4377
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4378<p>The optional !nontemporal metadata must reference a single metatadata
4379 name <index> corresponding to a metadata node with one i32 entry of
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]4380 value 1. The existence of the !nontemporal metatadata on the
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4381 instruction tells the optimizer and code generator that this load is
4382 not expected to be reused in the cache. The code generator may
4383 select special instructions to save cache bandwidth, such as the
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]4384 MOVNT instruction on x86.</p>
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4385
4386
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4387<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4388<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4389 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4390 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4391 does not exceed the minimum number of bytes needed to hold all bits of the
4392 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4393 writing a value of a type like <tt>i20</tt> with a size that is not an
4394 integral number of bytes, it is unspecified what happens to the extra bits
4395 that do not belong to the type, but they will typically be overwritten.</p>
4396
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4397<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4398<pre>
4399 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]4400 store i32 3, i32* %ptr <i>; yields {void}</i>
4401 %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]4402</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4403
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4404</div>
4405
4406<!-- _______________________________________________________________________ -->
4407<div class="doc_subsubsection">
4408 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4409</div>
4410
4411<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4412
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4413<h5>Syntax:</h5>
4414<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4415 &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]4416 &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]4417</pre>
4418
4419<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4420<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4421 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4422 It performs address calculation only and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4423
4424<h5>Arguments:</h5>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4425<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnere92fc832009-07-29 06:44:13 +0000[diff] [blame]4426 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4427 elements of the aggregate object are indexed. The interpretation of each
4428 index is dependent on the type being indexed into. The first index always
4429 indexes the pointer value given as the first argument, the second index
4430 indexes a value of the type pointed to (not necessarily the value directly
4431 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4432 indexed into must be a pointer value, subsequent types can be arrays,
4433 vectors, structs and unions. Note that subsequent types being indexed into
4434 can never be pointers, since that would require loading the pointer before
4435 continuing calculation.</p>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4436
4437<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]4438 When indexing into a (optionally packed) structure or union, only <tt>i32</tt>
4439 integer <b>constants</b> are allowed. When indexing into an array, pointer
4440 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]4441 constant.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4442
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4443<p>For example, let's consider a C code fragment and how it gets compiled to
4444 LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4445
4446<div class="doc_code">
4447<pre>
4448struct RT {
4449 char A;
4450 int B[10][20];
4451 char C;
4452};
4453struct ST {
4454 int X;
4455 double Y;
4456 struct RT Z;
4457};
4458
4459int *foo(struct ST *s) {
4460 return &amp;s[1].Z.B[5][13];
4461}
4462</pre>
4463</div>
4464
4465<p>The LLVM code generated by the GCC frontend is:</p>
4466
4467<div class="doc_code">
4468<pre>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]4469%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4470%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4471
Dan Gohman47360842009-07-25 02:23:48 +0000[diff] [blame]4472define i32* @foo(%ST* %s) {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4473entry:
4474 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4475 ret i32* %reg
4476}
4477</pre>
4478</div>
4479
4480<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4481<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]4482 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4483 }</tt>' type, a structure. The second index indexes into the third element
4484 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4485 i8 }</tt>' type, another structure. The third index indexes into the second
4486 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4487 array. The two dimensions of the array are subscripted into, yielding an
4488 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4489 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4490
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4491<p>Note that it is perfectly legal to index partially through a structure,
4492 returning a pointer to an inner element. Because of this, the LLVM code for
4493 the given testcase is equivalent to:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4494
4495<pre>
Dan Gohman47360842009-07-25 02:23:48 +0000[diff] [blame]4496 define i32* @foo(%ST* %s) {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4497 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
4498 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4499 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
4500 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4501 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4502 ret i32* %t5
4503 }
4504</pre>
4505
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4506<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohmanf7263862010-04-23 15:23:32 +0000[diff] [blame]4507 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
4508 base pointer is not an <i>in bounds</i> address of an allocated object,
4509 or if any of the addresses that would be formed by successive addition of
4510 the offsets implied by the indices to the base address with infinitely
4511 precise arithmetic are not an <i>in bounds</i> address of that allocated
4512 object. The <i>in bounds</i> addresses for an allocated object are all
4513 the addresses that point into the object, plus the address one byte past
4514 the end.</p>
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4515
4516<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4517 the base address with silently-wrapping two's complement arithmetic, and
4518 the result value of the <tt>getelementptr</tt> may be outside the object
4519 pointed to by the base pointer. The result value may not necessarily be
4520 used to access memory though, even if it happens to point into allocated
4521 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4522 section for more information.</p>
4523
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4524<p>The getelementptr instruction is often confusing. For some more insight into
4525 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4526
4527<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4528<pre>
4529 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4530 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4531 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4532 %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]4533 <i>; yields i8*:eptr</i>
4534 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta4f9a0dc2009-04-25 07:27:44 +0000[diff] [blame]4535 <i>; yields i32*:iptr</i>
Sanjiv Gupta1e46c582009-04-24 16:38:13 +0000[diff] [blame]4536 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4537</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4538
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4539</div>
4540
4541<!-- ======================================================================= -->
4542<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
4543</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4544
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4545<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4546
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4547<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4548 which all take a single operand and a type. They perform various bit
4549 conversions on the operand.</p>
4550
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4551</div>
4552
4553<!-- _______________________________________________________________________ -->
4554<div class="doc_subsubsection">
4555 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4556</div>
4557<div class="doc_text">
4558
4559<h5>Syntax:</h5>
4560<pre>
4561 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4562</pre>
4563
4564<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4565<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4566 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4567
4568<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4569<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4570 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4571 size and type of the result, which must be
4572 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4573 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4574 allowed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4575
4576<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4577<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4578 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4579 source size must be larger than the destination size, <tt>trunc</tt> cannot
4580 be a <i>no-op cast</i>. It will always truncate bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4581
4582<h5>Example:</h5>
4583<pre>
4584 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
4585 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4586 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4587</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4588
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4589</div>
4590
4591<!-- _______________________________________________________________________ -->
4592<div class="doc_subsubsection">
4593 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4594</div>
4595<div class="doc_text">
4596
4597<h5>Syntax:</h5>
4598<pre>
4599 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4600</pre>
4601
4602<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4603<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4604 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4605
4606
4607<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4608<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]4609 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4610 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]4611 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4612 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4613
4614<h5>Semantics:</h5>
4615<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]4616 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4617
4618<p>When zero extending from i1, the result will always be either 0 or 1.</p>
4619
4620<h5>Example:</h5>
4621<pre>
4622 %X = zext i32 257 to i64 <i>; yields i64:257</i>
4623 %Y = zext i1 true to i32 <i>; yields i32:1</i>
4624</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4625
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4626</div>
4627
4628<!-- _______________________________________________________________________ -->
4629<div class="doc_subsubsection">
4630 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4631</div>
4632<div class="doc_text">
4633
4634<h5>Syntax:</h5>
4635<pre>
4636 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4637</pre>
4638
4639<h5>Overview:</h5>
4640<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4641
4642<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4643<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]4644 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4645 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]4646 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4647 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4648
4649<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4650<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4651 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4652 of the type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4653
4654<p>When sign extending from i1, the extension always results in -1 or 0.</p>
4655
4656<h5>Example:</h5>
4657<pre>
4658 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
4659 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
4660</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4661
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4662</div>
4663
4664<!-- _______________________________________________________________________ -->
4665<div class="doc_subsubsection">
4666 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4667</div>
4668
4669<div class="doc_text">
4670
4671<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4672<pre>
4673 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4674</pre>
4675
4676<h5>Overview:</h5>
4677<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4678 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4679
4680<h5>Arguments:</h5>
4681<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4682 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4683 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]4684 <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]4685 <i>no-op cast</i>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4686
4687<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4688<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4689 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4690 <a href="#t_floating">floating point</a> type. If the value cannot fit
4691 within the destination type, <tt>ty2</tt>, then the results are
4692 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4693
4694<h5>Example:</h5>
4695<pre>
4696 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4697 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4698</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4699
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4700</div>
4701
4702<!-- _______________________________________________________________________ -->
4703<div class="doc_subsubsection">
4704 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4705</div>
4706<div class="doc_text">
4707
4708<h5>Syntax:</h5>
4709<pre>
4710 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4711</pre>
4712
4713<h5>Overview:</h5>
4714<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]4715 floating point value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4716
4717<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4718<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4719 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4720 a <a href="#t_floating">floating point</a> type to cast it to. The source
4721 type must be smaller than the destination type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4722
4723<h5>Semantics:</h5>
4724<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4725 <a href="#t_floating">floating point</a> type to a larger
4726 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4727 used to make a <i>no-op cast</i> because it always changes bits. Use
4728 <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]4729
4730<h5>Example:</h5>
4731<pre>
4732 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4733 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4734</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4735
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4736</div>
4737
4738<!-- _______________________________________________________________________ -->
4739<div class="doc_subsubsection">
4740 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
4741</div>
4742<div class="doc_text">
4743
4744<h5>Syntax:</h5>
4745<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4746 &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]4747</pre>
4748
4749<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4750<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4751 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4752
4753<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4754<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4755 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4756 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4757 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4758 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4759
4760<h5>Semantics:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4761<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4762 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4763 towards zero) unsigned integer value. If the value cannot fit
4764 in <tt>ty2</tt>, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4765
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4766<h5>Example:</h5>
4767<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4768 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4769 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4770 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4771</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4772
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4773</div>
4774
4775<!-- _______________________________________________________________________ -->
4776<div class="doc_subsubsection">
4777 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
4778</div>
4779<div class="doc_text">
4780
4781<h5>Syntax:</h5>
4782<pre>
4783 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4784</pre>
4785
4786<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4787<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4788 <a href="#t_floating">floating point</a> <tt>value</tt> to
4789 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4790
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4791<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4792<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4793 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4794 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4795 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4796 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4797
4798<h5>Semantics:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4799<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4800 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4801 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4802 the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4803
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4804<h5>Example:</h5>
4805<pre>
4806 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4807 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4808 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4809</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4810
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4811</div>
4812
4813<!-- _______________________________________________________________________ -->
4814<div class="doc_subsubsection">
4815 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
4816</div>
4817<div class="doc_text">
4818
4819<h5>Syntax:</h5>
4820<pre>
4821 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4822</pre>
4823
4824<h5>Overview:</h5>
4825<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4826 integer and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4827
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4828<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4829<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]4830 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4831 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4832 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4833 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4834
4835<h5>Semantics:</h5>
4836<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4837 integer quantity and converts it to the corresponding floating point
4838 value. If the value cannot fit in the floating point value, the results are
4839 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4840
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4841<h5>Example:</h5>
4842<pre>
4843 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4844 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4845</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4846
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4847</div>
4848
4849<!-- _______________________________________________________________________ -->
4850<div class="doc_subsubsection">
4851 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
4852</div>
4853<div class="doc_text">
4854
4855<h5>Syntax:</h5>
4856<pre>
4857 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4858</pre>
4859
4860<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4861<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4862 and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4863
4864<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4865<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]4866 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4867 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4868 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4869 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4870
4871<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4872<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4873 quantity and converts it to the corresponding floating point value. If the
4874 value cannot fit in the floating point value, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4875
4876<h5>Example:</h5>
4877<pre>
4878 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4879 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4880</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4881
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4882</div>
4883
4884<!-- _______________________________________________________________________ -->
4885<div class="doc_subsubsection">
4886 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4887</div>
4888<div class="doc_text">
4889
4890<h5>Syntax:</h5>
4891<pre>
4892 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4893</pre>
4894
4895<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4896<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4897 the integer type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4898
4899<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4900<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4901 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4902 <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]4903
4904<h5>Semantics:</h5>
4905<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4906 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4907 truncating or zero extending that value to the size of the integer type. If
4908 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4909 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4910 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4911 change.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4912
4913<h5>Example:</h5>
4914<pre>
4915 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4916 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
4917</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4918
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4919</div>
4920
4921<!-- _______________________________________________________________________ -->
4922<div class="doc_subsubsection">
4923 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4924</div>
4925<div class="doc_text">
4926
4927<h5>Syntax:</h5>
4928<pre>
4929 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4930</pre>
4931
4932<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4933<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4934 pointer type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4935
4936<h5>Arguments:</h5>
4937<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4938 value to cast, and a type to cast it to, which must be a
4939 <a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4940
4941<h5>Semantics:</h5>
4942<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4943 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4944 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4945 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4946 than the size of a pointer then a zero extension is done. If they are the
4947 same size, nothing is done (<i>no-op cast</i>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4948
4949<h5>Example:</h5>
4950<pre>
4951 %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]4952 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4953 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4954</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4955
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4956</div>
4957
4958<!-- _______________________________________________________________________ -->
4959<div class="doc_subsubsection">
4960 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
4961</div>
4962<div class="doc_text">
4963
4964<h5>Syntax:</h5>
4965<pre>
4966 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4967</pre>
4968
4969<h5>Overview:</h5>
4970<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4971 <tt>ty2</tt> without changing any bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4972
4973<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4974<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4975 non-aggregate first class value, and a type to cast it to, which must also be
4976 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4977 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4978 identical. If the source type is a pointer, the destination type must also be
4979 a pointer. This instruction supports bitwise conversion of vectors to
4980 integers and to vectors of other types (as long as they have the same
4981 size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4982
4983<h5>Semantics:</h5>
4984<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4985 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4986 this conversion. The conversion is done as if the <tt>value</tt> had been
4987 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4988 be converted to other pointer types with this instruction. To convert
4989 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4990 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4991
4992<h5>Example:</h5>
4993<pre>
4994 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
4995 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4996 %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]4997</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4998
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4999</div>
5000
5001<!-- ======================================================================= -->
5002<div class="doc_subsection"> <a name="otherops">Other Operations</a> </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
5006<p>The instructions in this category are the "miscellaneous" instructions, which
5007 defy better classification.</p>
5008
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5009</div>
5010
5011<!-- _______________________________________________________________________ -->
5012<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
5013</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5014
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5015<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5016
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5017<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5018<pre>
5019 &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]5020</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5021
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5022<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5023<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
5024 boolean values based on comparison of its two integer, integer vector, or
5025 pointer operands.</p>
5026
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5027<h5>Arguments:</h5>
5028<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5029 the condition code indicating the kind of comparison to perform. It is not a
5030 value, just a keyword. The possible condition code are:</p>
5031
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5032<ol>
5033 <li><tt>eq</tt>: equal</li>
5034 <li><tt>ne</tt>: not equal </li>
5035 <li><tt>ugt</tt>: unsigned greater than</li>
5036 <li><tt>uge</tt>: unsigned greater or equal</li>
5037 <li><tt>ult</tt>: unsigned less than</li>
5038 <li><tt>ule</tt>: unsigned less or equal</li>
5039 <li><tt>sgt</tt>: signed greater than</li>
5040 <li><tt>sge</tt>: signed greater or equal</li>
5041 <li><tt>slt</tt>: signed less than</li>
5042 <li><tt>sle</tt>: signed less or equal</li>
5043</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5044
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5045<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5046 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5047 typed. They must also be identical types.</p>
5048
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5049<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5050<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5051 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]5052 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]5053 result, as follows:</p>
5054
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5055<ol>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5056 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5057 <tt>false</tt> otherwise. No sign interpretation is necessary or
5058 performed.</li>
5059
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5060 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5061 <tt>false</tt> otherwise. No sign interpretation is necessary or
5062 performed.</li>
5063
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5064 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5065 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5066
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5067 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5068 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5069 to <tt>op2</tt>.</li>
5070
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5071 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5072 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5073
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5074 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5075 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5076
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5077 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5078 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5079
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5080 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5081 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5082 to <tt>op2</tt>.</li>
5083
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5084 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5085 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5086
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5087 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5088 <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]5089</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5090
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5091<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5092 values are compared as if they were integers.</p>
5093
5094<p>If the operands are integer vectors, then they are compared element by
5095 element. The result is an <tt>i1</tt> vector with the same number of elements
5096 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5097
5098<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5099<pre>
5100 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5101 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5102 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5103 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5104 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5105 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
5106</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]5107
5108<p>Note that the code generator does not yet support vector types with
5109 the <tt>icmp</tt> instruction.</p>
5110
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5111</div>
5112
5113<!-- _______________________________________________________________________ -->
5114<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5115</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5116
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5117<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5118
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5119<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5120<pre>
5121 &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]5122</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5123
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5124<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5125<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5126 values based on comparison of its operands.</p>
5127
5128<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]5129(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5130
5131<p>If the operands are floating point vectors, then the result type is a vector
5132 of boolean with the same number of elements as the operands being
5133 compared.</p>
5134
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5135<h5>Arguments:</h5>
5136<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5137 the condition code indicating the kind of comparison to perform. It is not a
5138 value, just a keyword. The possible condition code are:</p>
5139
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5140<ol>
5141 <li><tt>false</tt>: no comparison, always returns false</li>
5142 <li><tt>oeq</tt>: ordered and equal</li>
5143 <li><tt>ogt</tt>: ordered and greater than </li>
5144 <li><tt>oge</tt>: ordered and greater than or equal</li>
5145 <li><tt>olt</tt>: ordered and less than </li>
5146 <li><tt>ole</tt>: ordered and less than or equal</li>
5147 <li><tt>one</tt>: ordered and not equal</li>
5148 <li><tt>ord</tt>: ordered (no nans)</li>
5149 <li><tt>ueq</tt>: unordered or equal</li>
5150 <li><tt>ugt</tt>: unordered or greater than </li>
5151 <li><tt>uge</tt>: unordered or greater than or equal</li>
5152 <li><tt>ult</tt>: unordered or less than </li>
5153 <li><tt>ule</tt>: unordered or less than or equal</li>
5154 <li><tt>une</tt>: unordered or not equal</li>
5155 <li><tt>uno</tt>: unordered (either nans)</li>
5156 <li><tt>true</tt>: no comparison, always returns true</li>
5157</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5158
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5159<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5160 <i>unordered</i> means that either operand may be a QNAN.</p>
5161
5162<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5163 a <a href="#t_floating">floating point</a> type or
5164 a <a href="#t_vector">vector</a> of floating point type. They must have
5165 identical types.</p>
5166
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5167<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]5168<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5169 according to the condition code given as <tt>cond</tt>. If the operands are
5170 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]5171 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5172 follows:</p>
5173
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5174<ol>
5175 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5176
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5177 <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]5178 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5179
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5180 <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]5181 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5182
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5183 <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]5184 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5185
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5186 <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]5187 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5188
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5189 <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]5190 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5191
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5192 <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]5193 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5194
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5195 <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]5196
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5197 <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]5198 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5199
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5200 <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]5201 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5202
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5203 <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]5204 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5205
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5206 <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]5207 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5208
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5209 <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]5210 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5211
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5212 <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]5213 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5214
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5215 <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]5216
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5217 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5218</ol>
5219
5220<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5221<pre>
5222 &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]5223 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5224 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5225 &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]5226</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]5227
5228<p>Note that the code generator does not yet support vector types with
5229 the <tt>fcmp</tt> instruction.</p>
5230
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5231</div>
5232
5233<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]5234<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5235 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5236</div>
5237
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5238<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5239
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5240<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5241<pre>
5242 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5243</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5244
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5245<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5246<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5247 SSA graph representing the function.</p>
5248
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5249<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5250<p>The type of the incoming values is specified with the first type field. After
5251 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5252 one pair for each predecessor basic block of the current block. Only values
5253 of <a href="#t_firstclass">first class</a> type may be used as the value
5254 arguments to the PHI node. Only labels may be used as the label
5255 arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5256
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5257<p>There must be no non-phi instructions between the start of a basic block and
5258 the PHI instructions: i.e. PHI instructions must be first in a basic
5259 block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5260
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5261<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5262 occur on the edge from the corresponding predecessor block to the current
5263 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5264 value on the same edge).</p>
Jay Foad8e2fd2c2009-06-03 10:20:10 +0000[diff] [blame]5265
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5266<h5>Semantics:</h5>
5267<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5268 specified by the pair corresponding to the predecessor basic block that
5269 executed just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5270
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5271<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5272<pre>
5273Loop: ; Infinite loop that counts from 0 on up...
5274 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5275 %nextindvar = add i32 %indvar, 1
5276 br label %Loop
5277</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5278
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5279</div>
5280
5281<!-- _______________________________________________________________________ -->
5282<div class="doc_subsubsection">
5283 <a name="i_select">'<tt>select</tt>' Instruction</a>
5284</div>
5285
5286<div class="doc_text">
5287
5288<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5289<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]5290 &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>
5291
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5292 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5293</pre>
5294
5295<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5296<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5297 condition, without branching.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5298
5299
5300<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5301<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5302 values indicating the condition, and two values of the
5303 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5304 vectors and the condition is a scalar, then entire vectors are selected, not
5305 individual elements.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5306
5307<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5308<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5309 first value argument; otherwise, it returns the second value argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5310
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5311<p>If the condition is a vector of i1, then the value arguments must be vectors
5312 of the same size, and the selection is done element by element.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5313
5314<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5315<pre>
5316 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
5317</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]5318
5319<p>Note that the code generator does not yet support conditions
5320 with vector type.</p>
5321
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5322</div>
5323
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5324<!-- _______________________________________________________________________ -->
5325<div class="doc_subsubsection">
5326 <a name="i_call">'<tt>call</tt>' Instruction</a>
5327</div>
5328
5329<div class="doc_text">
5330
5331<h5>Syntax:</h5>
5332<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]5333 &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]5334</pre>
5335
5336<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5337<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
5338
5339<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5340<p>This instruction requires several arguments:</p>
5341
5342<ol>
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]5343 <li>The optional "tail" marker indicates that the callee function does not
5344 access any allocas or varargs in the caller. Note that calls may be
5345 marked "tail" even if they do not occur before
5346 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5347 present, the function call is eligible for tail call optimization,
5348 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Chengcc7495c2010-03-08 21:05:02 +0000[diff] [blame]5349 optimized into a jump</a>. The code generator may optimize calls marked
5350 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5351 sibling call optimization</a> when the caller and callee have
5352 matching signatures, or 2) forced tail call optimization when the
5353 following extra requirements are met:
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]5354 <ul>
5355 <li>Caller and callee both have the calling
5356 convention <tt>fastcc</tt>.</li>
5357 <li>The call is in tail position (ret immediately follows call and ret
5358 uses value of call or is void).</li>
5359 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohman1be84f02010-03-02 01:08:11 +0000[diff] [blame]5360 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]5361 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5362 constraints are met.</a></li>
5363 </ul>
5364 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5365
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5366 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5367 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]5368 defaults to using C calling conventions. The calling convention of the
5369 call must match the calling convention of the target function, or else the
5370 behavior is undefined.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5371
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5372 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5373 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5374 '<tt>inreg</tt>' attributes are valid here.</li>
5375
5376 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5377 type of the return value. Functions that return no value are marked
5378 <tt><a href="#t_void">void</a></tt>.</li>
5379
5380 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5381 being invoked. The argument types must match the types implied by this
5382 signature. This type can be omitted if the function is not varargs and if
5383 the function type does not return a pointer to a function.</li>
5384
5385 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5386 be invoked. In most cases, this is a direct function invocation, but
5387 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5388 to function value.</li>
5389
5390 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner553fb1e2010-03-02 06:36:51 +0000[diff] [blame]5391 signature argument types and parameter attributes. All arguments must be
5392 of <a href="#t_firstclass">first class</a> type. If the function
5393 signature indicates the function accepts a variable number of arguments,
5394 the extra arguments can be specified.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5395
5396 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5397 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5398 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5399</ol>
5400
5401<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5402<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5403 a specified function, with its incoming arguments bound to the specified
5404 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5405 function, control flow continues with the instruction after the function
5406 call, and the return value of the function is bound to the result
5407 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5408
5409<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5410<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]5411 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]5412 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
5413 %X = tail call i32 @foo() <i>; yields i32</i>
5414 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5415 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]5416
5417 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5418 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]5419 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5420 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +0000[diff] [blame]5421 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +0000[diff] [blame]5422 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5423</pre>
5424
Dale Johannesen9fcf4a92009-09-24 18:38:21 +0000[diff] [blame]5425<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen4730cd32009-09-25 17:04:42 +0000[diff] [blame]5426standard C99 library as being the C99 library functions, and may perform
5427optimizations or generate code for them under that assumption. This is
5428something we'd like to change in the future to provide better support for
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]5429freestanding environments and non-C-based languages.</p>
Dale Johannesen9fcf4a92009-09-24 18:38:21 +0000[diff] [blame]5430
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5431</div>
5432
5433<!-- _______________________________________________________________________ -->
5434<div class="doc_subsubsection">
5435 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
5436</div>
5437
5438<div class="doc_text">
5439
5440<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5441<pre>
5442 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
5443</pre>
5444
5445<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5446<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5447 the "variable argument" area of a function call. It is used to implement the
5448 <tt>va_arg</tt> macro in C.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5449
5450<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5451<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5452 argument. It returns a value of the specified argument type and increments
5453 the <tt>va_list</tt> to point to the next argument. The actual type
5454 of <tt>va_list</tt> is target specific.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5455
5456<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5457<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5458 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5459 to the next argument. For more information, see the variable argument
5460 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5461
5462<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]5463 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5464 function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5465
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5466<p><tt>va_arg</tt> is an LLVM instruction instead of
5467 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5468 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5469
5470<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5471<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5472
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5473<p>Note that the code generator does not yet fully support va_arg on many
5474 targets. Also, it does not currently support va_arg with aggregate types on
5475 any target.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]5476
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5477</div>
5478
5479<!-- *********************************************************************** -->
5480<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5481<!-- *********************************************************************** -->
5482
5483<div class="doc_text">
5484
5485<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5486 well known names and semantics and are required to follow certain
5487 restrictions. Overall, these intrinsics represent an extension mechanism for
5488 the LLVM language that does not require changing all of the transformations
5489 in LLVM when adding to the language (or the bitcode reader/writer, the
5490 parser, etc...).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5491
5492<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5493 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5494 begin with this prefix. Intrinsic functions must always be external
5495 functions: you cannot define the body of intrinsic functions. Intrinsic
5496 functions may only be used in call or invoke instructions: it is illegal to
5497 take the address of an intrinsic function. Additionally, because intrinsic
5498 functions are part of the LLVM language, it is required if any are added that
5499 they be documented here.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5500
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5501<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5502 family of functions that perform the same operation but on different data
5503 types. Because LLVM can represent over 8 million different integer types,
5504 overloading is used commonly to allow an intrinsic function to operate on any
5505 integer type. One or more of the argument types or the result type can be
5506 overloaded to accept any integer type. Argument types may also be defined as
5507 exactly matching a previous argument's type or the result type. This allows
5508 an intrinsic function which accepts multiple arguments, but needs all of them
5509 to be of the same type, to only be overloaded with respect to a single
5510 argument or the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5511
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5512<p>Overloaded intrinsics will have the names of its overloaded argument types
5513 encoded into its function name, each preceded by a period. Only those types
5514 which are overloaded result in a name suffix. Arguments whose type is matched
5515 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5516 can take an integer of any width and returns an integer of exactly the same
5517 integer width. This leads to a family of functions such as
5518 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5519 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5520 suffix is required. Because the argument's type is matched against the return
5521 type, it does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5522
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5523<p>To learn how to add an intrinsic function, please see the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5524 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5525
5526</div>
5527
5528<!-- ======================================================================= -->
5529<div class="doc_subsection">
5530 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5531</div>
5532
5533<div class="doc_text">
5534
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5535<p>Variable argument support is defined in LLVM with
5536 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5537 intrinsic functions. These functions are related to the similarly named
5538 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5539
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5540<p>All of these functions operate on arguments that use a target-specific value
5541 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5542 not define what this type is, so all transformations should be prepared to
5543 handle these functions regardless of the type used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5544
5545<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]5546 instruction and the variable argument handling intrinsic functions are
5547 used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5548
5549<div class="doc_code">
5550<pre>
5551define i32 @test(i32 %X, ...) {
5552 ; Initialize variable argument processing
5553 %ap = alloca i8*
5554 %ap2 = bitcast i8** %ap to i8*
5555 call void @llvm.va_start(i8* %ap2)
5556
5557 ; Read a single integer argument
5558 %tmp = va_arg i8** %ap, i32
5559
5560 ; Demonstrate usage of llvm.va_copy and llvm.va_end
5561 %aq = alloca i8*
5562 %aq2 = bitcast i8** %aq to i8*
5563 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
5564 call void @llvm.va_end(i8* %aq2)
5565
5566 ; Stop processing of arguments.
5567 call void @llvm.va_end(i8* %ap2)
5568 ret i32 %tmp
5569}
5570
5571declare void @llvm.va_start(i8*)
5572declare void @llvm.va_copy(i8*, i8*)
5573declare void @llvm.va_end(i8*)
5574</pre>
5575</div>
5576
5577</div>
5578
5579<!-- _______________________________________________________________________ -->
5580<div class="doc_subsubsection">
5581 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
5582</div>
5583
5584
5585<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5586
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5587<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5588<pre>
5589 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5590</pre>
5591
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5592<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5593<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5594 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]5595
5596<h5>Arguments:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5597<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]5598
5599<h5>Semantics:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5600<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]5601 macro available in C. In a target-dependent way, it initializes
5602 the <tt>va_list</tt> element to which the argument points, so that the next
5603 call to <tt>va_arg</tt> will produce the first variable argument passed to
5604 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5605 need to know the last argument of the function as the compiler can figure
5606 that out.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5607
5608</div>
5609
5610<!-- _______________________________________________________________________ -->
5611<div class="doc_subsubsection">
5612 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
5613</div>
5614
5615<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5616
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5617<h5>Syntax:</h5>
5618<pre>
5619 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5620</pre>
5621
5622<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5623<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5624 which has been initialized previously
5625 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5626 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5627
5628<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5629<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
5630
5631<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5632<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]5633 macro available in C. In a target-dependent way, it destroys
5634 the <tt>va_list</tt> element to which the argument points. Calls
5635 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5636 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5637 with calls to <tt>llvm.va_end</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5638
5639</div>
5640
5641<!-- _______________________________________________________________________ -->
5642<div class="doc_subsubsection">
5643 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
5644</div>
5645
5646<div class="doc_text">
5647
5648<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5649<pre>
5650 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
5651</pre>
5652
5653<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5654<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5655 from the source argument list to the destination argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5656
5657<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5658<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]5659 The second argument is a pointer to a <tt>va_list</tt> element to copy
5660 from.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5661
5662<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5663<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]5664 macro available in C. In a target-dependent way, it copies the
5665 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5666 element. This intrinsic is necessary because
5667 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5668 arbitrarily complex and require, for example, memory allocation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5669
5670</div>
5671
5672<!-- ======================================================================= -->
5673<div class="doc_subsection">
5674 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5675</div>
5676
5677<div class="doc_text">
5678
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5679<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5680Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5681intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5682roots on the stack</a>, as well as garbage collector implementations that
5683require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5684barriers. Front-ends for type-safe garbage collected languages should generate
5685these intrinsics to make use of the LLVM garbage collectors. For more details,
5686see <a href="GarbageCollection.html">Accurate Garbage Collection with
5687LLVM</a>.</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5688
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5689<p>The garbage collection intrinsics only operate on objects in the generic
5690 address space (address space zero).</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5691
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5692</div>
5693
5694<!-- _______________________________________________________________________ -->
5695<div class="doc_subsubsection">
5696 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
5697</div>
5698
5699<div class="doc_text">
5700
5701<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5702<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5703 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5704</pre>
5705
5706<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5707<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]5708 the code generator, and allows some metadata to be associated with it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5709
5710<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5711<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5712 root pointer. The second pointer (which must be either a constant or a
5713 global value address) contains the meta-data to be associated with the
5714 root.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5715
5716<h5>Semantics:</h5>
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]5717<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]5718 location. At compile-time, the code generator generates information to allow
5719 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5720 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5721 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5722
5723</div>
5724
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5725<!-- _______________________________________________________________________ -->
5726<div class="doc_subsubsection">
5727 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
5728</div>
5729
5730<div class="doc_text">
5731
5732<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5733<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5734 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5735</pre>
5736
5737<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5738<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5739 locations, allowing garbage collector implementations that require read
5740 barriers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5741
5742<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5743<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]5744 allocated from the garbage collector. The first object is a pointer to the
5745 start of the referenced object, if needed by the language runtime (otherwise
5746 null).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5747
5748<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5749<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5750 instruction, but may be replaced with substantially more complex code by the
5751 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5752 may only be used in a function which <a href="#gc">specifies a GC
5753 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5754
5755</div>
5756
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5757<!-- _______________________________________________________________________ -->
5758<div class="doc_subsubsection">
5759 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
5760</div>
5761
5762<div class="doc_text">
5763
5764<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5765<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5766 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5767</pre>
5768
5769<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5770<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5771 locations, allowing garbage collector implementations that require write
5772 barriers (such as generational or reference counting collectors).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5773
5774<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5775<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]5776 object to store it to, and the third is the address of the field of Obj to
5777 store to. If the runtime does not require a pointer to the object, Obj may
5778 be null.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5779
5780<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5781<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5782 instruction, but may be replaced with substantially more complex code by the
5783 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5784 may only be used in a function which <a href="#gc">specifies a GC
5785 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5786
5787</div>
5788
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5789<!-- ======================================================================= -->
5790<div class="doc_subsection">
5791 <a name="int_codegen">Code Generator Intrinsics</a>
5792</div>
5793
5794<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5795
5796<p>These intrinsics are provided by LLVM to expose special features that may
5797 only be implemented with code generator support.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5798
5799</div>
5800
5801<!-- _______________________________________________________________________ -->
5802<div class="doc_subsubsection">
5803 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
5804</div>
5805
5806<div class="doc_text">
5807
5808<h5>Syntax:</h5>
5809<pre>
5810 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
5811</pre>
5812
5813<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5814<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5815 target-specific value indicating the return address of the current function
5816 or one of its callers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5817
5818<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5819<p>The argument to this intrinsic indicates which function to return the address
5820 for. Zero indicates the calling function, one indicates its caller, etc.
5821 The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5822
5823<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5824<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5825 indicating the return address of the specified call frame, or zero if it
5826 cannot be identified. The value returned by this intrinsic is likely to be
5827 incorrect or 0 for arguments other than zero, so it should only be used for
5828 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5829
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5830<p>Note that calling this intrinsic does not prevent function inlining or other
5831 aggressive transformations, so the value returned may not be that of the
5832 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5833
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5834</div>
5835
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5836<!-- _______________________________________________________________________ -->
5837<div class="doc_subsubsection">
5838 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
5839</div>
5840
5841<div class="doc_text">
5842
5843<h5>Syntax:</h5>
5844<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5845 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5846</pre>
5847
5848<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5849<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5850 target-specific frame pointer value for the specified stack frame.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5851
5852<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5853<p>The argument to this intrinsic indicates which function to return the frame
5854 pointer for. Zero indicates the calling function, one indicates its caller,
5855 etc. The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5856
5857<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5858<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5859 indicating the frame address of the specified call frame, or zero if it
5860 cannot be identified. The value returned by this intrinsic is likely to be
5861 incorrect or 0 for arguments other than zero, so it should only be used for
5862 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5863
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5864<p>Note that calling this intrinsic does not prevent function inlining or other
5865 aggressive transformations, so the value returned may not be that of the
5866 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5867
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5868</div>
5869
5870<!-- _______________________________________________________________________ -->
5871<div class="doc_subsubsection">
5872 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
5873</div>
5874
5875<div class="doc_text">
5876
5877<h5>Syntax:</h5>
5878<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5879 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5880</pre>
5881
5882<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5883<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5884 of the function stack, for use
5885 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5886 useful for implementing language features like scoped automatic variable
5887 sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5888
5889<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5890<p>This intrinsic returns a opaque pointer value that can be passed
5891 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5892 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5893 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5894 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5895 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5896 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5897
5898</div>
5899
5900<!-- _______________________________________________________________________ -->
5901<div class="doc_subsubsection">
5902 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
5903</div>
5904
5905<div class="doc_text">
5906
5907<h5>Syntax:</h5>
5908<pre>
5909 declare void @llvm.stackrestore(i8 * %ptr)
5910</pre>
5911
5912<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5913<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5914 the function stack to the state it was in when the
5915 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5916 executed. This is useful for implementing language features like scoped
5917 automatic variable sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5918
5919<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5920<p>See the description
5921 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5922
5923</div>
5924
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5925<!-- _______________________________________________________________________ -->
5926<div class="doc_subsubsection">
5927 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
5928</div>
5929
5930<div class="doc_text">
5931
5932<h5>Syntax:</h5>
5933<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5934 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]5935</pre>
5936
5937<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5938<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5939 insert a prefetch instruction if supported; otherwise, it is a noop.
5940 Prefetches have no effect on the behavior of the program but can change its
5941 performance characteristics.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5942
5943<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5944<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5945 specifier determining if the fetch should be for a read (0) or write (1),
5946 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5947 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5948 and <tt>locality</tt> arguments must be constant integers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5949
5950<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5951<p>This intrinsic does not modify the behavior of the program. In particular,
5952 prefetches cannot trap and do not produce a value. On targets that support
5953 this intrinsic, the prefetch can provide hints to the processor cache for
5954 better performance.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5955
5956</div>
5957
5958<!-- _______________________________________________________________________ -->
5959<div class="doc_subsubsection">
5960 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
5961</div>
5962
5963<div class="doc_text">
5964
5965<h5>Syntax:</h5>
5966<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5967 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5968</pre>
5969
5970<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5971<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5972 Counter (PC) in a region of code to simulators and other tools. The method
5973 is target specific, but it is expected that the marker will use exported
5974 symbols to transmit the PC of the marker. The marker makes no guarantees
5975 that it will remain with any specific instruction after optimizations. It is
5976 possible that the presence of a marker will inhibit optimizations. The
5977 intended use is to be inserted after optimizations to allow correlations of
5978 simulation runs.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5979
5980<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5981<p><tt>id</tt> is a numerical id identifying the marker.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5982
5983<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5984<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]5985 not support this intrinsic may ignore it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5986
5987</div>
5988
5989<!-- _______________________________________________________________________ -->
5990<div class="doc_subsubsection">
5991 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5992</div>
5993
5994<div class="doc_text">
5995
5996<h5>Syntax:</h5>
5997<pre>
5998 declare i64 @llvm.readcyclecounter( )
5999</pre>
6000
6001<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6002<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
6003 counter register (or similar low latency, high accuracy clocks) on those
6004 targets that support it. On X86, it should map to RDTSC. On Alpha, it
6005 should map to RPCC. As the backing counters overflow quickly (on the order
6006 of 9 seconds on alpha), this should only be used for small timings.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6007
6008<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6009<p>When directly supported, reading the cycle counter should not modify any
6010 memory. Implementations are allowed to either return a application specific
6011 value or a system wide value. On backends without support, this is lowered
6012 to a constant 0.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6013
6014</div>
6015
6016<!-- ======================================================================= -->
6017<div class="doc_subsection">
6018 <a name="int_libc">Standard C Library Intrinsics</a>
6019</div>
6020
6021<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6022
6023<p>LLVM provides intrinsics for a few important standard C library functions.
6024 These intrinsics allow source-language front-ends to pass information about
6025 the alignment of the pointer arguments to the code generator, providing
6026 opportunity for more efficient code generation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6027
6028</div>
6029
6030<!-- _______________________________________________________________________ -->
6031<div class="doc_subsubsection">
6032 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
6033</div>
6034
6035<div class="doc_text">
6036
6037<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6038<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]6039 integer bit width and for different address spaces. Not all targets support
6040 all bit widths however.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6041
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6042<pre>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6043 declare void @llvm.memcpy.p0i8.p0i8.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
6044 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
6045 declare void @llvm.memcpy.p0i8.p0i8.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
6046 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6047</pre>
6048
6049<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6050<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6051 source location to the destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6052
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6053<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6054 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6055 and the pointers can be in specified address spaces.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6056
6057<h5>Arguments:</h5>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6058
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6059<p>The first argument is a pointer to the destination, the second is a pointer
6060 to the source. The third argument is an integer argument specifying the
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6061 number of bytes to copy, the fourth argument is the alignment of the
6062 source and destination locations, and the fifth is a boolean indicating a
6063 volatile access.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6064
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]6065<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]6066 then the caller guarantees that both the source and destination pointers are
6067 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6068
Jeffrey Yasskin6dc467f2010-04-26 21:21:24 +0000[diff] [blame]6069<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6070 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6071 The detailed access behavior is not very cleanly specified and it is unwise
6072 to depend on it.</p>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6073
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6074<h5>Semantics:</h5>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6075
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6076<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6077 source location to the destination location, which are not allowed to
6078 overlap. It copies "len" bytes of memory over. If the argument is known to
6079 be aligned to some boundary, this can be specified as the fourth argument,
6080 otherwise it should be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6081
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6082</div>
6083
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6084<!-- _______________________________________________________________________ -->
6085<div class="doc_subsubsection">
6086 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
6087</div>
6088
6089<div class="doc_text">
6090
6091<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]6092<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]6093 width and for different address space. Not all targets support all bit
6094 widths however.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6095
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6096<pre>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6097 declare void @llvm.memmove.p0i8.p0i8.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
6098 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
6099 declare void @llvm.memmove.p0i8.p0i8.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
6100 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6101</pre>
6102
6103<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6104<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6105 source location to the destination location. It is similar to the
6106 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6107 overlap.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6108
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6109<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6110 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6111 and the pointers can be in specified address spaces.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6112
6113<h5>Arguments:</h5>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6114
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6115<p>The first argument is a pointer to the destination, the second is a pointer
6116 to the source. The third argument is an integer argument specifying the
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6117 number of bytes to copy, the fourth argument is the alignment of the
6118 source and destination locations, and the fifth is a boolean indicating a
6119 volatile access.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6120
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]6121<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]6122 then the caller guarantees that the source and destination pointers are
6123 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6124
Jeffrey Yasskin6dc467f2010-04-26 21:21:24 +0000[diff] [blame]6125<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6126 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6127 The detailed access behavior is not very cleanly specified and it is unwise
6128 to depend on it.</p>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6129
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6130<h5>Semantics:</h5>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6131
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6132<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6133 source location to the destination location, which may overlap. It copies
6134 "len" bytes of memory over. If the argument is known to be aligned to some
6135 boundary, this can be specified as the fourth argument, otherwise it should
6136 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6137
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6138</div>
6139
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6140<!-- _______________________________________________________________________ -->
6141<div class="doc_subsubsection">
6142 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
6143</div>
6144
6145<div class="doc_text">
6146
6147<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]6148<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]6149 width and for different address spaces. Not all targets support all bit
6150 widths however.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6151
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6152<pre>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6153 declare void @llvm.memset.p0i8.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerc0dfafe2010-04-08 00:54:34 +0000[diff] [blame]6154 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6155 declare void @llvm.memset.p0i8.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerc0dfafe2010-04-08 00:54:34 +0000[diff] [blame]6156 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6157</pre>
6158
6159<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6160<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6161 particular byte value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6162
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6163<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6164 intrinsic does not return a value, takes extra alignment/volatile arguments,
6165 and the destination can be in an arbitrary address space.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6166
6167<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6168<p>The first argument is a pointer to the destination to fill, the second is the
6169 byte value to fill it with, the third argument is an integer argument
6170 specifying the number of bytes to fill, and the fourth argument is the known
6171 alignment of destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6172
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]6173<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]6174 then the caller guarantees that the destination pointer is aligned to that
6175 boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6176
Jeffrey Yasskin6dc467f2010-04-26 21:21:24 +0000[diff] [blame]6177<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6178 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6179 The detailed access behavior is not very cleanly specified and it is unwise
6180 to depend on it.</p>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6181
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6182<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6183<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6184 at the destination location. If the argument is known to be aligned to some
6185 boundary, this can be specified as the fourth argument, otherwise it should
6186 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6187
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6188</div>
6189
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6190<!-- _______________________________________________________________________ -->
6191<div class="doc_subsubsection">
6192 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
6193</div>
6194
6195<div class="doc_text">
6196
6197<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6198<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6199 floating point or vector of floating point type. Not all targets support all
6200 types however.</p>
6201
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6202<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]6203 declare float @llvm.sqrt.f32(float %Val)
6204 declare double @llvm.sqrt.f64(double %Val)
6205 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6206 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6207 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6208</pre>
6209
6210<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6211<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6212 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6213 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6214 behavior for negative numbers other than -0.0 (which allows for better
6215 optimization, because there is no need to worry about errno being
6216 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]6217
6218<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6219<p>The argument and return value are floating point numbers of the same
6220 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6221
6222<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6223<p>This function returns the sqrt of the specified operand if it is a
6224 nonnegative floating point number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6225
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6226</div>
6227
6228<!-- _______________________________________________________________________ -->
6229<div class="doc_subsubsection">
6230 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
6231</div>
6232
6233<div class="doc_text">
6234
6235<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6236<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6237 floating point or vector of floating point type. Not all targets support all
6238 types however.</p>
6239
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6240<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]6241 declare float @llvm.powi.f32(float %Val, i32 %power)
6242 declare double @llvm.powi.f64(double %Val, i32 %power)
6243 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6244 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6245 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6246</pre>
6247
6248<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6249<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6250 specified (positive or negative) power. The order of evaluation of
6251 multiplications is not defined. When a vector of floating point type is
6252 used, the second argument remains a scalar integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6253
6254<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6255<p>The second argument is an integer power, and the first is a value to raise to
6256 that power.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6257
6258<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6259<p>This function returns the first value raised to the second power with an
6260 unspecified sequence of rounding operations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6261
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6262</div>
6263
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6264<!-- _______________________________________________________________________ -->
6265<div class="doc_subsubsection">
6266 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6267</div>
6268
6269<div class="doc_text">
6270
6271<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6272<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6273 floating point or vector of floating point type. Not all targets support all
6274 types however.</p>
6275
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6276<pre>
6277 declare float @llvm.sin.f32(float %Val)
6278 declare double @llvm.sin.f64(double %Val)
6279 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6280 declare fp128 @llvm.sin.f128(fp128 %Val)
6281 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6282</pre>
6283
6284<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6285<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6286
6287<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6288<p>The argument and return value are floating point numbers of the same
6289 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6290
6291<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6292<p>This function returns the sine of the specified operand, returning the same
6293 values as the libm <tt>sin</tt> functions would, and handles error conditions
6294 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6295
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6296</div>
6297
6298<!-- _______________________________________________________________________ -->
6299<div class="doc_subsubsection">
6300 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6301</div>
6302
6303<div class="doc_text">
6304
6305<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6306<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6307 floating point or vector of floating point type. Not all targets support all
6308 types however.</p>
6309
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6310<pre>
6311 declare float @llvm.cos.f32(float %Val)
6312 declare double @llvm.cos.f64(double %Val)
6313 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6314 declare fp128 @llvm.cos.f128(fp128 %Val)
6315 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6316</pre>
6317
6318<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6319<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6320
6321<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6322<p>The argument and return value are floating point numbers of the same
6323 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6324
6325<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6326<p>This function returns the cosine of the specified operand, returning the same
6327 values as the libm <tt>cos</tt> functions would, and handles error conditions
6328 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6329
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6330</div>
6331
6332<!-- _______________________________________________________________________ -->
6333<div class="doc_subsubsection">
6334 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6335</div>
6336
6337<div class="doc_text">
6338
6339<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6340<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6341 floating point or vector of floating point type. Not all targets support all
6342 types however.</p>
6343
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6344<pre>
6345 declare float @llvm.pow.f32(float %Val, float %Power)
6346 declare double @llvm.pow.f64(double %Val, double %Power)
6347 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6348 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6349 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6350</pre>
6351
6352<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6353<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6354 specified (positive or negative) power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6355
6356<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6357<p>The second argument is a floating point power, and the first is a value to
6358 raise to that power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6359
6360<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6361<p>This function returns the first value raised to the second power, returning
6362 the same values as the libm <tt>pow</tt> functions would, and handles error
6363 conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6364
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6365</div>
6366
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6367<!-- ======================================================================= -->
6368<div class="doc_subsection">
6369 <a name="int_manip">Bit Manipulation Intrinsics</a>
6370</div>
6371
6372<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6373
6374<p>LLVM provides intrinsics for a few important bit manipulation operations.
6375 These allow efficient code generation for some algorithms.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6376
6377</div>
6378
6379<!-- _______________________________________________________________________ -->
6380<div class="doc_subsubsection">
6381 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
6382</div>
6383
6384<div class="doc_text">
6385
6386<h5>Syntax:</h5>
6387<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6388 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6389
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6390<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6391 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6392 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6393 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6394</pre>
6395
6396<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6397<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6398 values with an even number of bytes (positive multiple of 16 bits). These
6399 are useful for performing operations on data that is not in the target's
6400 native byte order.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6401
6402<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6403<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6404 and low byte of the input i16 swapped. Similarly,
6405 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6406 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6407 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6408 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6409 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6410 more, respectively).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6411
6412</div>
6413
6414<!-- _______________________________________________________________________ -->
6415<div class="doc_subsubsection">
6416 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
6417</div>
6418
6419<div class="doc_text">
6420
6421<h5>Syntax:</h5>
6422<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]6423 width. Not all targets support all bit widths however.</p>
6424
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6425<pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6426 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6427 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6428 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6429 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6430 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6431</pre>
6432
6433<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6434<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6435 in a value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6436
6437<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6438<p>The only argument is the value to be counted. The argument may be of any
6439 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6440
6441<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6442<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]6443
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6444</div>
6445
6446<!-- _______________________________________________________________________ -->
6447<div class="doc_subsubsection">
6448 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
6449</div>
6450
6451<div class="doc_text">
6452
6453<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6454<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6455 integer bit width. Not all targets support all bit widths however.</p>
6456
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6457<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6458 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6459 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6460 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6461 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6462 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6463</pre>
6464
6465<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6466<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6467 leading zeros in a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6468
6469<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6470<p>The only argument is the value to be counted. The argument may be of any
6471 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6472
6473<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6474<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6475 zeros in a variable. If the src == 0 then the result is the size in bits of
6476 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6477
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6478</div>
6479
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6480<!-- _______________________________________________________________________ -->
6481<div class="doc_subsubsection">
6482 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
6483</div>
6484
6485<div class="doc_text">
6486
6487<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6488<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6489 integer bit width. Not all targets support all bit widths however.</p>
6490
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6491<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6492 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6493 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6494 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6495 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6496 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6497</pre>
6498
6499<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6500<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6501 trailing zeros.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6502
6503<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6504<p>The only argument is the value to be counted. The argument may be of any
6505 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6506
6507<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6508<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6509 zeros in a variable. If the src == 0 then the result is the size in bits of
6510 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6511
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6512</div>
6513
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6514<!-- ======================================================================= -->
6515<div class="doc_subsection">
6516 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6517</div>
6518
6519<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6520
6521<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6522
6523</div>
6524
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6525<!-- _______________________________________________________________________ -->
6526<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6527 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6528</div>
6529
6530<div class="doc_text">
6531
6532<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6533<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]6534 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6535
6536<pre>
6537 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6538 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6539 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6540</pre>
6541
6542<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6543<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6544 a signed addition of the two arguments, and indicate whether an overflow
6545 occurred during the signed summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6546
6547<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6548<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]6549 be of integer types of any bit width, but they must have the same bit
6550 width. The second element of the result structure must be of
6551 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6552 undergo signed addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6553
6554<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6555<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6556 a signed addition of the two variables. They return a structure &mdash; the
6557 first element of which is the signed summation, and the second element of
6558 which is a bit specifying if the signed summation resulted in an
6559 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6560
6561<h5>Examples:</h5>
6562<pre>
6563 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6564 %sum = extractvalue {i32, i1} %res, 0
6565 %obit = extractvalue {i32, i1} %res, 1
6566 br i1 %obit, label %overflow, label %normal
6567</pre>
6568
6569</div>
6570
6571<!-- _______________________________________________________________________ -->
6572<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6573 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6574</div>
6575
6576<div class="doc_text">
6577
6578<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6579<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]6580 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6581
6582<pre>
6583 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6584 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6585 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6586</pre>
6587
6588<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6589<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6590 an unsigned addition of the two arguments, and indicate whether a carry
6591 occurred during the unsigned summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6592
6593<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6594<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]6595 be of integer types of any bit width, but they must have the same bit
6596 width. The second element of the result structure must be of
6597 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6598 undergo unsigned addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6599
6600<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6601<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6602 an unsigned addition of the two arguments. They return a structure &mdash;
6603 the first element of which is the sum, and the second element of which is a
6604 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6605
6606<h5>Examples:</h5>
6607<pre>
6608 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6609 %sum = extractvalue {i32, i1} %res, 0
6610 %obit = extractvalue {i32, i1} %res, 1
6611 br i1 %obit, label %carry, label %normal
6612</pre>
6613
6614</div>
6615
6616<!-- _______________________________________________________________________ -->
6617<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6618 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6619</div>
6620
6621<div class="doc_text">
6622
6623<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6624<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]6625 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6626
6627<pre>
6628 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6629 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6630 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6631</pre>
6632
6633<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6634<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6635 a signed subtraction of the two arguments, and indicate whether an overflow
6636 occurred during the signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6637
6638<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6639<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]6640 be of integer types of any bit width, but they must have the same bit
6641 width. The second element of the result structure must be of
6642 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6643 undergo signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6644
6645<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6646<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6647 a signed subtraction of the two arguments. They return a structure &mdash;
6648 the first element of which is the subtraction, and the second element of
6649 which is a bit specifying if the signed subtraction resulted in an
6650 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6651
6652<h5>Examples:</h5>
6653<pre>
6654 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6655 %sum = extractvalue {i32, i1} %res, 0
6656 %obit = extractvalue {i32, i1} %res, 1
6657 br i1 %obit, label %overflow, label %normal
6658</pre>
6659
6660</div>
6661
6662<!-- _______________________________________________________________________ -->
6663<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6664 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6665</div>
6666
6667<div class="doc_text">
6668
6669<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6670<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]6671 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6672
6673<pre>
6674 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6675 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6676 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6677</pre>
6678
6679<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6680<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6681 an unsigned subtraction of the two arguments, and indicate whether an
6682 overflow occurred during the unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6683
6684<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6685<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]6686 be of integer types of any bit width, but they must have the same bit
6687 width. The second element of the result structure must be of
6688 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6689 undergo unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6690
6691<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6692<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6693 an unsigned subtraction of the two arguments. They return a structure &mdash;
6694 the first element of which is the subtraction, and the second element of
6695 which is a bit specifying if the unsigned subtraction resulted in an
6696 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6697
6698<h5>Examples:</h5>
6699<pre>
6700 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6701 %sum = extractvalue {i32, i1} %res, 0
6702 %obit = extractvalue {i32, i1} %res, 1
6703 br i1 %obit, label %overflow, label %normal
6704</pre>
6705
6706</div>
6707
6708<!-- _______________________________________________________________________ -->
6709<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6710 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6711</div>
6712
6713<div class="doc_text">
6714
6715<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6716<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]6717 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6718
6719<pre>
6720 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6721 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6722 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6723</pre>
6724
6725<h5>Overview:</h5>
6726
6727<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6728 a signed multiplication of the two arguments, and indicate whether an
6729 overflow occurred during the signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6730
6731<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6732<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]6733 be of integer types of any bit width, but they must have the same bit
6734 width. The second element of the result structure must be of
6735 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6736 undergo signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6737
6738<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6739<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6740 a signed multiplication of the two arguments. They return a structure &mdash;
6741 the first element of which is the multiplication, and the second element of
6742 which is a bit specifying if the signed multiplication resulted in an
6743 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6744
6745<h5>Examples:</h5>
6746<pre>
6747 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6748 %sum = extractvalue {i32, i1} %res, 0
6749 %obit = extractvalue {i32, i1} %res, 1
6750 br i1 %obit, label %overflow, label %normal
6751</pre>
6752
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6753</div>
6754
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6755<!-- _______________________________________________________________________ -->
6756<div class="doc_subsubsection">
6757 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6758</div>
6759
6760<div class="doc_text">
6761
6762<h5>Syntax:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6763<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]6764 on any integer bit width.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6765
6766<pre>
6767 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6768 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6769 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6770</pre>
6771
6772<h5>Overview:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6773<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6774 a unsigned multiplication of the two arguments, and indicate whether an
6775 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6776
6777<h5>Arguments:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6778<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]6779 be of integer types of any bit width, but they must have the same bit
6780 width. The second element of the result structure must be of
6781 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6782 undergo unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6783
6784<h5>Semantics:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6785<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6786 an unsigned multiplication of the two arguments. They return a structure
6787 &mdash; the first element of which is the multiplication, and the second
6788 element of which is a bit specifying if the unsigned multiplication resulted
6789 in an overflow.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6790
6791<h5>Examples:</h5>
6792<pre>
6793 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6794 %sum = extractvalue {i32, i1} %res, 0
6795 %obit = extractvalue {i32, i1} %res, 1
6796 br i1 %obit, label %overflow, label %normal
6797</pre>
6798
6799</div>
6800
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6801<!-- ======================================================================= -->
6802<div class="doc_subsection">
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]6803 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
6804</div>
6805
6806<div class="doc_text">
6807
Chris Lattnere5969c62010-03-15 04:12:21 +0000[diff] [blame]6808<p>Half precision floating point is a storage-only format. This means that it is
6809 a dense encoding (in memory) but does not support computation in the
6810 format.</p>
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6811
Chris Lattnere5969c62010-03-15 04:12:21 +0000[diff] [blame]6812<p>This means that code must first load the half-precision floating point
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6813 value as an i16, then convert it to float with <a
6814 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
6815 Computation can then be performed on the float value (including extending to
Chris Lattnere5969c62010-03-15 04:12:21 +0000[diff] [blame]6816 double etc). To store the value back to memory, it is first converted to
6817 float if needed, then converted to i16 with
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6818 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
6819 storing as an i16 value.</p>
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]6820</div>
6821
6822<!-- _______________________________________________________________________ -->
6823<div class="doc_subsubsection">
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6824 <a name="int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a>
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]6825</div>
6826
6827<div class="doc_text">
6828
6829<h5>Syntax:</h5>
6830<pre>
6831 declare i16 @llvm.convert.to.fp16(f32 %a)
6832</pre>
6833
6834<h5>Overview:</h5>
6835<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6836 a conversion from single precision floating point format to half precision
6837 floating point format.</p>
6838
6839<h5>Arguments:</h5>
6840<p>The intrinsic function contains single argument - the value to be
6841 converted.</p>
6842
6843<h5>Semantics:</h5>
6844<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6845 a conversion from single precision floating point format to half precision
Chris Lattnere5969c62010-03-15 04:12:21 +0000[diff] [blame]6846 floating point format. The return value is an <tt>i16</tt> which
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6847 contains the converted number.</p>
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]6848
6849<h5>Examples:</h5>
6850<pre>
6851 %res = call i16 @llvm.convert.to.fp16(f32 %a)
6852 store i16 %res, i16* @x, align 2
6853</pre>
6854
6855</div>
6856
6857<!-- _______________________________________________________________________ -->
6858<div class="doc_subsubsection">
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6859 <a name="int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a>
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]6860</div>
6861
6862<div class="doc_text">
6863
6864<h5>Syntax:</h5>
6865<pre>
6866 declare f32 @llvm.convert.from.fp16(i16 %a)
6867</pre>
6868
6869<h5>Overview:</h5>
6870<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
6871 a conversion from half precision floating point format to single precision
6872 floating point format.</p>
6873
6874<h5>Arguments:</h5>
6875<p>The intrinsic function contains single argument - the value to be
6876 converted.</p>
6877
6878<h5>Semantics:</h5>
6879<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattnere5969c62010-03-15 04:12:21 +0000[diff] [blame]6880 conversion from half single precision floating point format to single
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6881 precision floating point format. The input half-float value is represented by
6882 an <tt>i16</tt> value.</p>
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]6883
6884<h5>Examples:</h5>
6885<pre>
6886 %a = load i16* @x, align 2
6887 %res = call f32 @llvm.convert.from.fp16(i16 %a)
6888</pre>
6889
6890</div>
6891
6892<!-- ======================================================================= -->
6893<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6894 <a name="int_debugger">Debugger Intrinsics</a>
6895</div>
6896
6897<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6898
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6899<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6900 prefix), are described in
6901 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6902 Level Debugging</a> document.</p>
6903
6904</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6905
6906<!-- ======================================================================= -->
6907<div class="doc_subsection">
6908 <a name="int_eh">Exception Handling Intrinsics</a>
6909</div>
6910
6911<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6912
6913<p>The LLVM exception handling intrinsics (which all start with
6914 <tt>llvm.eh.</tt> prefix), are described in
6915 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6916 Handling</a> document.</p>
6917
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6918</div>
6919
6920<!-- ======================================================================= -->
6921<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6922 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6923</div>
6924
6925<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6926
6927<p>This intrinsic makes it possible to excise one parameter, marked with
6928 the <tt>nest</tt> attribute, from a function. The result is a callable
6929 function pointer lacking the nest parameter - the caller does not need to
6930 provide a value for it. Instead, the value to use is stored in advance in a
6931 "trampoline", a block of memory usually allocated on the stack, which also
6932 contains code to splice the nest value into the argument list. This is used
6933 to implement the GCC nested function address extension.</p>
6934
6935<p>For example, if the function is
6936 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6937 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6938 follows:</p>
6939
6940<div class="doc_code">
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6941<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6942 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6943 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6944 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6945 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6946</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6947</div>
6948
6949<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6950 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6951
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6952</div>
6953
6954<!-- _______________________________________________________________________ -->
6955<div class="doc_subsubsection">
6956 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6957</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6958
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6959<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6960
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6961<h5>Syntax:</h5>
6962<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6963 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]6964</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6965
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6966<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6967<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6968 function pointer suitable for executing it.</p>
6969
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6970<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6971<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6972 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6973 sufficiently aligned block of memory; this memory is written to by the
6974 intrinsic. Note that the size and the alignment are target-specific - LLVM
6975 currently provides no portable way of determining them, so a front-end that
6976 generates this intrinsic needs to have some target-specific knowledge.
6977 The <tt>func</tt> argument must hold a function bitcast to
6978 an <tt>i8*</tt>.</p>
6979
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6980<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6981<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6982 dependent code, turning it into a function. A pointer to this function is
6983 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6984 function pointer type</a> before being called. The new function's signature
6985 is the same as that of <tt>func</tt> with any arguments marked with
6986 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6987 is allowed, and it must be of pointer type. Calling the new function is
6988 equivalent to calling <tt>func</tt> with the same argument list, but
6989 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6990 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6991 by <tt>tramp</tt> is modified, then the effect of any later call to the
6992 returned function pointer is undefined.</p>
6993
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6994</div>
6995
6996<!-- ======================================================================= -->
6997<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6998 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6999</div>
7000
7001<div class="doc_text">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7002
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7003<p>These intrinsic functions expand the "universal IR" of LLVM to represent
7004 hardware constructs for atomic operations and memory synchronization. This
7005 provides an interface to the hardware, not an interface to the programmer. It
7006 is aimed at a low enough level to allow any programming models or APIs
7007 (Application Programming Interfaces) which need atomic behaviors to map
7008 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
7009 hardware provides a "universal IR" for source languages, it also provides a
7010 starting point for developing a "universal" atomic operation and
7011 synchronization IR.</p>
7012
7013<p>These do <em>not</em> form an API such as high-level threading libraries,
7014 software transaction memory systems, atomic primitives, and intrinsic
7015 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
7016 application libraries. The hardware interface provided by LLVM should allow
7017 a clean implementation of all of these APIs and parallel programming models.
7018 No one model or paradigm should be selected above others unless the hardware
7019 itself ubiquitously does so.</p>
7020
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7021</div>
7022
7023<!-- _______________________________________________________________________ -->
7024<div class="doc_subsubsection">
7025 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
7026</div>
7027<div class="doc_text">
7028<h5>Syntax:</h5>
7029<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7030 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]7031</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7032
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7033<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7034<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
7035 specific pairs of memory access types.</p>
7036
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7037<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7038<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
7039 The first four arguments enables a specific barrier as listed below. The
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]7040 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7041 memory.</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7042
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7043<ul>
7044 <li><tt>ll</tt>: load-load barrier</li>
7045 <li><tt>ls</tt>: load-store barrier</li>
7046 <li><tt>sl</tt>: store-load barrier</li>
7047 <li><tt>ss</tt>: store-store barrier</li>
7048 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
7049</ul>
7050
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7051<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7052<p>This intrinsic causes the system to enforce some ordering constraints upon
7053 the loads and stores of the program. This barrier does not
7054 indicate <em>when</em> any events will occur, it only enforces
7055 an <em>order</em> in which they occur. For any of the specified pairs of load
7056 and store operations (f.ex. load-load, or store-load), all of the first
7057 operations preceding the barrier will complete before any of the second
7058 operations succeeding the barrier begin. Specifically the semantics for each
7059 pairing is as follows:</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7060
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7061<ul>
7062 <li><tt>ll</tt>: All loads before the barrier must complete before any load
7063 after the barrier begins.</li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7064 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7065 store after the barrier begins.</li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7066 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7067 store after the barrier begins.</li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7068 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7069 load after the barrier begins.</li>
7070</ul>
7071
7072<p>These semantics are applied with a logical "and" behavior when more than one
7073 is enabled in a single memory barrier intrinsic.</p>
7074
7075<p>Backends may implement stronger barriers than those requested when they do
7076 not support as fine grained a barrier as requested. Some architectures do
7077 not need all types of barriers and on such architectures, these become
7078 noops.</p>
7079
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7080<h5>Example:</h5>
7081<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7082%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7083%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7084 store i32 4, %ptr
7085
7086%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
7087 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
7088 <i>; guarantee the above finishes</i>
7089 store i32 8, %ptr <i>; before this begins</i>
7090</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7091
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7092</div>
7093
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7094<!-- _______________________________________________________________________ -->
7095<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7096 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7097</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7098
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7099<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7100
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7101<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7102<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
7103 any integer bit width and for different address spaces. Not all targets
7104 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7105
7106<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7107 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
7108 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
7109 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
7110 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]7111</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7112
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7113<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7114<p>This loads a value in memory and compares it to a given value. If they are
7115 equal, it stores a new value into the memory.</p>
7116
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7117<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7118<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
7119 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
7120 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
7121 this integer type. While any bit width integer may be used, targets may only
7122 lower representations they support in hardware.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7123
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7124<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7125<p>This entire intrinsic must be executed atomically. It first loads the value
7126 in memory pointed to by <tt>ptr</tt> and compares it with the
7127 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
7128 memory. The loaded value is yielded in all cases. This provides the
7129 equivalent of an atomic compare-and-swap operation within the SSA
7130 framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7131
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7132<h5>Examples:</h5>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7133<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7134%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7135%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7136 store i32 4, %ptr
7137
7138%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7139%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7140 <i>; yields {i32}:result1 = 4</i>
7141%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7142%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7143
7144%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7145%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7146 <i>; yields {i32}:result2 = 8</i>
7147%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
7148
7149%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
7150</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7151
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7152</div>
7153
7154<!-- _______________________________________________________________________ -->
7155<div class="doc_subsubsection">
7156 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
7157</div>
7158<div class="doc_text">
7159<h5>Syntax:</h5>
7160
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7161<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
7162 integer bit width. Not all targets support all bit widths however.</p>
7163
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7164<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7165 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
7166 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
7167 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
7168 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]7169</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7170
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7171<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7172<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
7173 the value from memory. It then stores the value in <tt>val</tt> in the memory
7174 at <tt>ptr</tt>.</p>
7175
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7176<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7177<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
7178 the <tt>val</tt> argument and the result must be integers of the same bit
7179 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
7180 integer type. The targets may only lower integer representations they
7181 support.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7182
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7183<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7184<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
7185 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
7186 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7187
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7188<h5>Examples:</h5>
7189<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7190%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7191%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7192 store i32 4, %ptr
7193
7194%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7195%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7196 <i>; yields {i32}:result1 = 4</i>
7197%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7198%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7199
7200%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7201%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7202 <i>; yields {i32}:result2 = 8</i>
7203
7204%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
7205%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
7206</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7207
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7208</div>
7209
7210<!-- _______________________________________________________________________ -->
7211<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7212 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7213
7214</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7215
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7216<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7217
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7218<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7219<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
7220 any integer bit width. Not all targets support all bit widths however.</p>
7221
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7222<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7223 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7224 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7225 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7226 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]7227</pre>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7228
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7229<h5>Overview:</h5>
7230<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
7231 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7232
7233<h5>Arguments:</h5>
7234<p>The intrinsic takes two arguments, the first a pointer to an integer value
7235 and the second an integer value. The result is also an integer value. These
7236 integer types can have any bit width, but they must all have the same bit
7237 width. The targets may only lower integer representations they support.</p>
7238
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7239<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7240<p>This intrinsic does a series of operations atomically. It first loads the
7241 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
7242 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]7243
7244<h5>Examples:</h5>
7245<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7246%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7247%ptr = bitcast i8* %mallocP to i32*
7248 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7249%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7250 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7251%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7252 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7253%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7254 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7255%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7256</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7257
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7258</div>
7259
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7260<!-- _______________________________________________________________________ -->
7261<div class="doc_subsubsection">
7262 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
7263
7264</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7265
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7266<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7267
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7268<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7269<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
7270 any integer bit width and for different address spaces. Not all targets
7271 support all bit widths however.</p>
7272
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7273<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7274 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7275 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7276 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7277 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]7278</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7279
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7280<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7281<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7282 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7283
7284<h5>Arguments:</h5>
7285<p>The intrinsic takes two arguments, the first a pointer to an integer value
7286 and the second an integer value. The result is also an integer value. These
7287 integer types can have any bit width, but they must all have the same bit
7288 width. The targets may only lower integer representations they support.</p>
7289
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7290<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7291<p>This intrinsic does a series of operations atomically. It first loads the
7292 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
7293 result to <tt>ptr</tt>. It yields the original value stored
7294 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7295
7296<h5>Examples:</h5>
7297<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7298%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7299%ptr = bitcast i8* %mallocP to i32*
7300 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7301%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7302 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7303%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7304 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7305%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7306 <i>; yields {i32}:result3 = 2</i>
7307%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
7308</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7309
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7310</div>
7311
7312<!-- _______________________________________________________________________ -->
7313<div class="doc_subsubsection">
7314 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
7315 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
7316 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
7317 <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]7318</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7319
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7320<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7321
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7322<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7323<p>These are overloaded intrinsics. You can
7324 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
7325 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7326 bit width and for different address spaces. Not all targets support all bit
7327 widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7328
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7329<pre>
7330 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7331 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7332 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7333 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]7334</pre>
7335
7336<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7337 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7338 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7339 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7340 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]7341</pre>
7342
7343<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7344 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7345 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7346 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7347 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]7348</pre>
7349
7350<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7351 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7352 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7353 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7354 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]7355</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7356
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7357<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7358<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7359 the value stored in memory at <tt>ptr</tt>. It yields the original value
7360 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7361
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7362<h5>Arguments:</h5>
7363<p>These intrinsics take two arguments, the first a pointer to an integer value
7364 and the second an integer value. The result is also an integer value. These
7365 integer types can have any bit width, but they must all have the same bit
7366 width. The targets may only lower integer representations they support.</p>
7367
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7368<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7369<p>These intrinsics does a series of operations atomically. They first load the
7370 value stored at <tt>ptr</tt>. They then do the bitwise
7371 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7372 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7373
7374<h5>Examples:</h5>
7375<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7376%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7377%ptr = bitcast i8* %mallocP to i32*
7378 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7379%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7380 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7381%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7382 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7383%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7384 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7385%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7386 <i>; yields {i32}:result3 = FF</i>
7387%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7388</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7389
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7390</div>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7391
7392<!-- _______________________________________________________________________ -->
7393<div class="doc_subsubsection">
7394 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7395 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7396 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7397 <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]7398</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7399
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7400<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7401
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7402<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7403<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7404 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7405 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7406 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7407
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7408<pre>
7409 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7410 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7411 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7412 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]7413</pre>
7414
7415<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7416 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7417 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7418 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7419 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]7420</pre>
7421
7422<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7423 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7424 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7425 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7426 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]7427</pre>
7428
7429<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7430 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7431 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7432 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7433 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]7434</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7435
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7436<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7437<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7438 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7439 original value at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7440
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7441<h5>Arguments:</h5>
7442<p>These intrinsics take two arguments, the first a pointer to an integer value
7443 and the second an integer value. The result is also an integer value. These
7444 integer types can have any bit width, but they must all have the same bit
7445 width. The targets may only lower integer representations they support.</p>
7446
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7447<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7448<p>These intrinsics does a series of operations atomically. They first load the
7449 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7450 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7451 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7452
7453<h5>Examples:</h5>
7454<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7455%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7456%ptr = bitcast i8* %mallocP to i32*
7457 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7458%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7459 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7460%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7461 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7462%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7463 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7464%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7465 <i>; yields {i32}:result3 = 8</i>
7466%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7467</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7468
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7469</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7470
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7471
7472<!-- ======================================================================= -->
7473<div class="doc_subsection">
7474 <a name="int_memorymarkers">Memory Use Markers</a>
7475</div>
7476
7477<div class="doc_text">
7478
7479<p>This class of intrinsics exists to information about the lifetime of memory
7480 objects and ranges where variables are immutable.</p>
7481
7482</div>
7483
7484<!-- _______________________________________________________________________ -->
7485<div class="doc_subsubsection">
7486 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7487</div>
7488
7489<div class="doc_text">
7490
7491<h5>Syntax:</h5>
7492<pre>
7493 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7494</pre>
7495
7496<h5>Overview:</h5>
7497<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7498 object's lifetime.</p>
7499
7500<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7501<p>The first argument is a constant integer representing the size of the
7502 object, or -1 if it is variable sized. The second argument is a pointer to
7503 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7504
7505<h5>Semantics:</h5>
7506<p>This intrinsic indicates that before this point in the code, the value of the
7507 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]7508 never be used and has an undefined value. A load from the pointer that
7509 precedes this intrinsic can be replaced with
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7510 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7511
7512</div>
7513
7514<!-- _______________________________________________________________________ -->
7515<div class="doc_subsubsection">
7516 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7517</div>
7518
7519<div class="doc_text">
7520
7521<h5>Syntax:</h5>
7522<pre>
7523 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7524</pre>
7525
7526<h5>Overview:</h5>
7527<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7528 object's lifetime.</p>
7529
7530<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7531<p>The first argument is a constant integer representing the size of the
7532 object, or -1 if it is variable sized. The second argument is a pointer to
7533 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7534
7535<h5>Semantics:</h5>
7536<p>This intrinsic indicates that after this point in the code, the value of the
7537 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7538 never be used and has an undefined value. Any stores into the memory object
7539 following this intrinsic may be removed as dead.
7540
7541</div>
7542
7543<!-- _______________________________________________________________________ -->
7544<div class="doc_subsubsection">
7545 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7546</div>
7547
7548<div class="doc_text">
7549
7550<h5>Syntax:</h5>
7551<pre>
7552 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7553</pre>
7554
7555<h5>Overview:</h5>
7556<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7557 a memory object will not change.</p>
7558
7559<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7560<p>The first argument is a constant integer representing the size of the
7561 object, or -1 if it is variable sized. The second argument is a pointer to
7562 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7563
7564<h5>Semantics:</h5>
7565<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7566 the return value, the referenced memory location is constant and
7567 unchanging.</p>
7568
7569</div>
7570
7571<!-- _______________________________________________________________________ -->
7572<div class="doc_subsubsection">
7573 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7574</div>
7575
7576<div class="doc_text">
7577
7578<h5>Syntax:</h5>
7579<pre>
7580 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7581</pre>
7582
7583<h5>Overview:</h5>
7584<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7585 a memory object are mutable.</p>
7586
7587<h5>Arguments:</h5>
7588<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7589 The second argument is a constant integer representing the size of the
7590 object, or -1 if it is variable sized and the third argument is a pointer
7591 to the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7592
7593<h5>Semantics:</h5>
7594<p>This intrinsic indicates that the memory is mutable again.</p>
7595
7596</div>
7597
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7598<!-- ======================================================================= -->
7599<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7600 <a name="int_general">General Intrinsics</a>
7601</div>
7602
7603<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7604
7605<p>This class of intrinsics is designed to be generic and has no specific
7606 purpose.</p>
7607
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7608</div>
7609
7610<!-- _______________________________________________________________________ -->
7611<div class="doc_subsubsection">
7612 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7613</div>
7614
7615<div class="doc_text">
7616
7617<h5>Syntax:</h5>
7618<pre>
7619 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7620</pre>
7621
7622<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7623<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7624
7625<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7626<p>The first argument is a pointer to a value, the second is a pointer to a
7627 global string, the third is a pointer to a global string which is the source
7628 file name, and the last argument is the line number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7629
7630<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7631<p>This intrinsic allows annotation of local variables with arbitrary strings.
7632 This can be useful for special purpose optimizations that want to look for
7633 these annotations. These have no other defined use, they are ignored by code
7634 generation and optimization.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7635
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7636</div>
7637
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7638<!-- _______________________________________________________________________ -->
7639<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]7640 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7641</div>
7642
7643<div class="doc_text">
7644
7645<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7646<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7647 any integer bit width.</p>
7648
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7649<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +0000[diff] [blame]7650 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7651 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7652 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7653 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7654 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]7655</pre>
7656
7657<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7658<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7659
7660<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7661<p>The first argument is an integer value (result of some expression), the
7662 second is a pointer to a global string, the third is a pointer to a global
7663 string which is the source file name, and the last argument is the line
7664 number. It returns the value of the first argument.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7665
7666<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7667<p>This intrinsic allows annotations to be put on arbitrary expressions with
7668 arbitrary strings. This can be useful for special purpose optimizations that
7669 want to look for these annotations. These have no other defined use, they
7670 are ignored by code generation and optimization.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7671
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7672</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7673
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7674<!-- _______________________________________________________________________ -->
7675<div class="doc_subsubsection">
7676 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7677</div>
7678
7679<div class="doc_text">
7680
7681<h5>Syntax:</h5>
7682<pre>
7683 declare void @llvm.trap()
7684</pre>
7685
7686<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7687<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7688
7689<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7690<p>None.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7691
7692<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7693<p>This intrinsics is lowered to the target dependent trap instruction. If the
7694 target does not have a trap instruction, this intrinsic will be lowered to
7695 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7696
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7697</div>
7698
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7699<!-- _______________________________________________________________________ -->
7700<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +0000[diff] [blame]7701 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7702</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7703
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7704<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7705
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7706<h5>Syntax:</h5>
7707<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7708 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7709</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7710
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7711<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7712<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7713 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7714 ensure that it is placed on the stack before local variables.</p>
7715
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7716<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7717<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7718 arguments. The first argument is the value loaded from the stack
7719 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7720 that has enough space to hold the value of the guard.</p>
7721
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7722<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7723<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7724 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7725 stack. This is to ensure that if a local variable on the stack is
7726 overwritten, it will destroy the value of the guard. When the function exits,
7727 the guard on the stack is checked against the original guard. If they're
7728 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7729 function.</p>
7730
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7731</div>
7732
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7733<!-- _______________________________________________________________________ -->
7734<div class="doc_subsubsection">
7735 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7736</div>
7737
7738<div class="doc_text">
7739
7740<h5>Syntax:</h5>
7741<pre>
Eric Christopher0101f9d2009-12-23 00:29:49 +0000[diff] [blame]7742 declare i32 @llvm.objectsize.i32( i8* &lt;object&gt;, i1 &lt;type&gt; )
7743 declare i64 @llvm.objectsize.i64( i8* &lt;object&gt;, i1 &lt;type&gt; )
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7744</pre>
7745
7746<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7747<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information
Eric Christopher184f44d2010-01-08 21:42:39 +0000[diff] [blame]7748 to the optimizers to discover at compile time either a) when an
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7749 operation like memcpy will either overflow a buffer that corresponds to
7750 an object, or b) to determine that a runtime check for overflow isn't
7751 necessary. An object in this context means an allocation of a
Eric Christopher0101f9d2009-12-23 00:29:49 +0000[diff] [blame]7752 specific class, structure, array, or other object.</p>
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7753
7754<h5>Arguments:</h5>
7755<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher0101f9d2009-12-23 00:29:49 +0000[diff] [blame]7756 argument is a pointer to or into the <tt>object</tt>. The second argument
7757 is a boolean 0 or 1. This argument determines whether you want the
7758 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
7759 1, variables are not allowed.</p>
7760
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7761<h5>Semantics:</h5>
7762<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7763 representing the size of the object concerned or <tt>i32/i64 -1 or 0</tt>
7764 (depending on the <tt>type</tt> argument if the size cannot be determined
7765 at compile time.</p>
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7766
7767</div>
7768
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7769<!-- *********************************************************************** -->
7770<hr>
7771<address>
7772 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]7773 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7774 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]7775 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7776
7777 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
7778 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
7779 Last modified: $Date$
7780</address>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]7781
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7782</body>
7783</html>